CN117730577A

CN117730577A - Communication method, device and computer readable medium in NTN system

Info

Publication number: CN117730577A
Application number: CN202180100561.7A
Authority: CN
Inventors: 陈景然; 卢飞
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2021-11-02
Filing date: 2021-12-03
Publication date: 2024-03-19
Also published as: WO2023077599A1

Abstract

The present disclosure provides a communication method, apparatus, and computer readable medium in an NTN system. According to a first aspect of the present disclosure there is provided a method of communication in a non-terrestrial network NTN providing communication with a network device for a user device UE via a plurality of satellite SATs, the plurality of SATs comprising a first SAT, the first SAT being connected to the UE, the plurality of SATs comprising a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISLs, each ISL corresponding to a satellite hop, characterised in that the method is applied to the first SAT, comprising sending link delay information to the UE, wherein the link delay information indicates a link delay corresponding to at least one of the one or more satellite transmission paths.

Description

Communication method, device and computer readable medium in NTN system

The present application claims priority from PCT patent application filed by the chinese patent office at month 11 and 02 of 2021, application number PCT/CN2021/128246, entitled "communication methods, apparatus, and computer readable media in NTN systems," the entire contents of which are incorporated herein by reference.

Technical Field

The present disclosure relates to non-terrestrial network (NTN) systems, and more particularly, to a communication method, apparatus, and computer readable medium in an NTN system.

Background

With the continuous development of communication technology, most of the global areas are covered by ground networks, but in areas such as deserts, forests, oceans and the like, or on vehicles moving at high speed such as airplanes, high-speed rails and the like, the coverage of the mobile networks is difficult to be covered by adopting a traditional ground base station mode due to the limitation of cost or physical conditions. In order to solve the network coverage problem in such a scenario, an NTN system has been developed, and a Satellite (SAT) communication system, which is an important component of the NTN system, has been receiving more and more attention because of the characteristics of long communication distance, large coverage area, flexible networking, and the like.

The SAT communication system has an advantage of a long communication distance, but a relatively large communication delay is inevitably generated between SATs due to a long communication distance. When a user terminal performs long-distance communication by means of a SAT system in an NTN system, a large communication time delay may not meet the requirement of user service on time delay, so that the service experience of a user is reduced, and even the service cannot be normally performed due to the extra time delay of a SAT link; on the other hand, for the service with higher communication delay requirement, such as V2X isochronous delay sensitive service, the link connection establishment failure can be caused, and the communication signaling is wasted.

Disclosure of Invention

The present disclosure provides a communication method, apparatus, and computer readable medium in an NTN system to indicate link latency in the NTN system.

According to a first aspect of the present disclosure, there is provided a communication method in a non-terrestrial network NTN, the NTN providing communication with a network device for a user device UE through a plurality of satellite SATs, the plurality of SATs including a first SAT, the first SAT being connected to the UE, the plurality of SATs including a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISLs, each ISL corresponding to one satellite hop, the method being applied to the first SAT, comprising sending link delay information to the UE, wherein the link delay information indicates a link delay corresponding to at least one of the one or more satellite transmission paths.

According to a second aspect of the present disclosure, there is provided a communication method in a non-terrestrial network NTN, the NTN providing communication with a network device for a user device UE through a plurality of SATs, the plurality of SATs including a first SAT, the first SAT being connected to the UE, the plurality of SATs including a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISLs, each ISL corresponding to one satellite hop, the method being applied to the second SAT, comprising: a first message is sent to the network device, wherein the first message comprises a NAS request message for a target service and the first message includes link delay information.

According to a third aspect of the present disclosure, there is provided a communication method in a non-terrestrial network NTN, the NTN providing communication with a network device for a user device UE through a plurality of SATs, the plurality of SATs including a first SAT, the first SAT being connected to the UE, the plurality of SATs including a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISLs, each ISL corresponding to one satellite hop, the method being applied to the UE, comprising receiving link delay information sent by a first SAT of the plurality of SATs, wherein the link delay information indicates a link delay corresponding to at least one satellite transmission path of the one or more satellite transmission paths; and determining whether to initiate a non-access stratum (NAS) request message aiming at the target service according to the link delay information.

According to a fourth aspect of the present disclosure, there is provided a communication method in a non-terrestrial network NTN, the NTN providing communication with a network device for a user equipment UE through a plurality of SATs, the plurality of SATs including a first SAT, the first SAT being connected to the UE, the plurality of SATs including a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISLs, each ISL corresponding to one satellite hop, the method being applied to the UE, comprising receiving link delay information sent by a first SAT of the plurality of SATs, wherein the link delay information indicates a link delay corresponding to at least one satellite transmission path of the one or more satellite transmission paths; and sending a non-access stratum (NAS) request message aiming at the target service, wherein the NAS request message comprises the link delay information.

According to a fifth aspect of the present disclosure, there is provided a communication method in a non-terrestrial network NTN, the NTN providing communication with a network device for a user device UE through a plurality of SATs, the plurality of SATs including a first SAT, the first SAT being connected to the UE, the plurality of SATs including a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISLs, each ISL corresponding to one satellite hop, the method being applied to the network device, comprising: receiving a first message from a second SAT in the plurality of SATs, wherein the first message is used for requesting a service corresponding to a target business, and the first message comprises link delay information; and determining whether to accept the NAS request aiming at the target service according to the link delay information.

According to a sixth aspect of the present disclosure, there is provided a communication method in a non-terrestrial network NTN, the NTN providing communication with a network device for a user equipment UE through a plurality of satellite SATs, the plurality of SATs including a first SAT connected to the UE, the plurality of SATs including a second SAT connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISLs, each ISL corresponding to one satellite hop, the method being applied to a third SAT included in the one or more satellite transmission paths, the method comprising receiving a first message requesting a service corresponding to a target traffic; determining link delay information; and determining whether to forward the first message according to the link delay information.

According to a seventh aspect of the present disclosure, there is provided a communication method in a non-terrestrial network NTN, the NTN providing communication with a network device for a user equipment UE through a plurality of SATs, the plurality of SATs including a first SAT, the first SAT being connected to the UE, the plurality of SATs including a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISLs, each ISL corresponding to one satellite hop, the method being applied to the first SAT, comprising receiving a NAS request message from the UE for a target service; determining a satellite transmission path delay threshold allowed by the delay requirement of the target service; and sending a first message, wherein the first message includes the allowed satellite transmission path delay threshold and the NAS request message.

According to an eighth aspect of the present disclosure, there is provided a satellite SAT located in a non-terrestrial network NTN for performing a communication method in the NTN, the satellite SAT being a first SAT of a plurality of SATs included in the NTN, the NTN providing communication with a network device for a user equipment UE through the plurality of SATs, the first SAT being connected to the UE, a second SAT of the plurality of SATs being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISL, each ISL corresponding to one satellite hop, the satellite SAT comprising a transmitting unit configured to transmit link delay information to the UE, wherein the link delay information indicates a link delay corresponding to at least one satellite transmission path of the one or more satellite transmission paths.

According to a ninth aspect of the present disclosure, there is provided a satellite SAT located in a non-terrestrial network NTN for performing a communication method in the NTN, the satellite SAT being a second SAT of a plurality of SATs included in the NTN, the NTN providing communication with a network device for a user equipment UE through the plurality of SATs, a first SAT of the plurality of SATs being connected to the UE, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISL, each ISL corresponding to one satellite hop, comprising: a sending unit configured to send a first message to the network device, wherein the first message comprises a NAS request message for a target service, and the first message comprises link delay information.

According to a tenth aspect of the present disclosure, there is provided a user equipment, UE, connected to a network device through a non-terrestrial network, NTN, wherein the NTN provides the UE with communication with the network device through a plurality of SATs, the plurality of SATs including a first SAT, the first SAT being connected to the UE, the plurality of SATs including a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links, ISLs, each ISL corresponding to one satellite hop, comprising a receiving unit configured to receive link delay information sent by a first SAT of the plurality of SATs, wherein the link delay information indicates a link delay corresponding to at least one satellite transmission path of the one or more satellite transmission paths; and the determining unit is configured to determine whether to initiate a non-access stratum NAS request message aiming at the target service according to the link delay information.

According to an eleventh aspect of the present disclosure, there is provided a user equipment UE connected to a network device through a non-terrestrial network NTN, wherein the NTN provides communication with the network device for the UE through a plurality of SATs, the plurality of SATs including a first SAT connected to the UE, the plurality of SATs including a second SAT connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected through inter-satellite links ISL, each ISL corresponding to one satellite hop, comprising a receiving unit configured to receive link delay information transmitted by a first SAT of the plurality of SATs, wherein the link delay information indicates a link delay corresponding to at least one satellite transmission path of the one or more satellite transmission paths; and the sending unit is configured to send a non-access stratum (NAS) request message aiming at the target service, wherein the NAS request message comprises the link delay information.

According to a twelfth aspect of the present disclosure, there is provided a network device connected to a user equipment UE through a non-terrestrial network NTN, the NTN providing communication with the network device UE through a plurality of SATs, the plurality of SATs including a first SAT connected to the UE, the plurality of SATs including a second SAT connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected through inter-satellite links ISLs, each ISL corresponding to one satellite hop, comprising: a receiving unit configured to receive a first message from a second SAT of the plurality of SATs, the first message being for requesting a service corresponding to a target traffic, and the first message including link delay information; and the determining unit is configured to determine whether to accept the NAS request for the target service according to the link delay information.

According to a thirteenth aspect of the present disclosure, there is provided a satellite SAT located in a non-terrestrial network NTN for performing a communication method in the NTN, the satellite SAT being a third SAT of a plurality of SATs included in the NTN, the NTN providing communication with a network device for a user equipment UE through the plurality of satellite SATs, the plurality of SATs including a first SAT, the first SAT being connected to the UE, the plurality of SATs including a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein the third SAT is located in the one or more satellite transmission paths, adjacent satellites in each satellite transmission path being connected by inter-satellite links ISL, each ISL corresponding to one satellite hop, characterized in that the method includes a receiving unit configured to receive a first message, the first message for requesting a service corresponding to a target service; a determining unit configured to determine link delay information; and a determining unit configured to determine whether to forward the first message according to the link delay information.

According to a fourteenth aspect of the present disclosure, there is provided a satellite SAT located in a non-terrestrial network NTN for performing a communication method in the NTN, the satellite SAT being a first SAT of a plurality of SATs included in the NTN, the NTN providing communication with a network device for a user equipment UE through the plurality of SATs, the first SAT being connected to the UE, the plurality of SATs including a second SAT connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISLs, each ISL corresponding to one satellite hop, comprising a receiving unit configured to receive a NAS request message for a target service from the UE; a determining unit configured to determine a satellite transmission path delay threshold allowed by a delay requirement of the target service; and a transmitting unit configured to transmit a first message, wherein the first message includes the allowed satellite transmission path delay threshold and the NAS request message.

According to a fifteenth aspect of the present disclosure, there is provided a satellite SAT located in a non-terrestrial network NTN, comprising: a processor and a memory having stored therein computer instructions which, when invoked and executed by the processor, cause the processor to perform the method of any of the above first, second, sixth or seventh aspects.

According to a sixteenth aspect of the present disclosure, there is provided a user equipment UE, comprising: a processor and a memory having stored therein computer instructions which, when invoked and executed by the processor, cause the processor to perform the method of any of the above third or fourth aspects.

According to a seventeenth aspect of the present disclosure, there is provided a network device, comprising: a processor and a memory having stored therein computer instructions which, when invoked and executed by the processor, cause the processor to perform the method of the fifth aspect described above.

According to an eighteenth aspect of the present disclosure, there is provided a computer readable storage medium, characterized in that it has stored thereon computer instructions which, when executed by a processor, cause the processor to perform the method of any of the above-mentioned first, second, sixth or seventh aspects.

According to a nineteenth aspect of the present disclosure, there is provided a computer readable storage medium, characterized in that it has stored thereon computer instructions which, when executed by a processor, cause the processor to perform the method of any of the above third or fourth aspects.

According to a twentieth aspect of the present disclosure, there is provided a computer readable storage medium having stored thereon computer instructions which, when executed by a processor, cause the processor to perform the method of the fifth aspect described above.

According to the technical scheme provided by the disclosure, the problem that the service link is failed to be established or the target service cannot be normally performed due to the additional link delay of the SAT link is avoided by indicating the link delay in the NTN system, so that the probability of successful establishment of the user service link in the NTN system is improved and normal user service experience is ensured.

Drawings

Aspects of the present disclosure are illustrated by way of example and not limitation in the figures of the accompanying drawings. In the drawings:

fig. 1 is a schematic architecture diagram of a wireless communication system according to an embodiment of the present disclosure;

fig. 2 is a schematic architecture diagram of an NTN system including a SAT communication system according to an embodiment of the present disclosure;

Fig. 3 is a schematic architecture diagram of an NTN system including a SAT communication system according to an embodiment of the present disclosure;

FIG. 4 is a schematic flow chart of a communication method according to an embodiment of the disclosure;

fig. 5 is a schematic flow chart of a communication method in an NTN system including a SAT communication system according to an embodiment of the present disclosure;

fig. 6 is a schematic flow chart of a communication method in an NTN system including a SAT communication system according to an embodiment of the disclosure;

fig. 7 is a schematic flow chart of a communication method in an NTN system including a SAT communication system according to an embodiment of the disclosure;

fig. 8 is a flowchart of a method implemented in an NTN system including a SAT communication system, according to an embodiment of the present disclosure;

fig. 9 is a flowchart of a method implemented in an NTN system including a SAT communication system, according to an embodiment of the present disclosure;

fig. 10 is a flowchart of a method implemented in an NTN system including a SAT communication system, according to an embodiment of the present disclosure;

FIG. 11 is a schematic flow diagram of a communication method performed by a SAT according to an embodiment of the disclosure;

fig. 12 is a schematic flow diagram of a communication method performed by a terminal device according to an embodiment of the disclosure;

Fig. 13 is a schematic flow diagram of a communication method performed by a terminal device according to an embodiment of the disclosure;

FIG. 14 is a schematic flow diagram of a communication method performed by a SAT according to an embodiment of the disclosure;

fig. 15 is a schematic flow diagram of a communication method performed by a network device according to an embodiment of the disclosure;

FIG. 16 is a schematic flow diagram of a communication method performed by a SAT according to an embodiment of the disclosure;

FIG. 17 is a schematic flow diagram of a communication method performed by a SAT according to an embodiment of the disclosure;

fig. 18 is a schematic block diagram of a terminal device according to an embodiment of the present disclosure;

FIG. 19 is a schematic block diagram of a SAT according to an embodiment of the disclosure;

fig. 20 is a schematic block diagram of a network device according to an embodiment of the present disclosure;

fig. 21 is a schematic block diagram of a communication device according to an embodiment of the present disclosure; and

fig. 22 is a schematic block diagram of a computer device according to an embodiment of the present disclosure.

Detailed Description

The inventive concept will now be described in more detail below with reference to the attached drawing figures, in which examples of embodiments of the inventive concept are shown. The inventive concept may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosed concept to those skilled in the art. It should also be noted that the embodiments are not mutually exclusive. Components from one embodiment may be assumed by default to be present/used in another embodiment. Any two or more of the embodiments described below may be combined with each other in any manner.

In general, all terms used herein are to be interpreted according to their ordinary meaning in the relevant art, unless a different meaning is clearly given and/or implied by the context in which it is used. All references to elements, devices, components, steps, etc. are to be interpreted openly as referring to at least one instance of an element, device, component, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless the steps are explicitly described as being followed or before another step and/or wherein it is implied that the steps must be followed or before another step. Any feature of any of the embodiments disclosed herein may be applicable to any other embodiment where appropriate. Likewise, any advantages of any of the embodiments may apply to any other embodiment, and vice versa. Other objects, features and advantages of the present disclosure will also be appreciated by those skilled in the art from the embodiments disclosed below.

Fig. 1 is a schematic architecture diagram of a wireless communication system 100 according to an embodiment of the present disclosure. Fig. 1 shows two radio access network (radio access network, RAN) devices 110, two terminal devices 130, and one Core Network (CN) device 120. The radio access network RAN apparatuses 110 respectively provide wireless communication services for the terminal apparatuses 130 within their geographical service areas, and the terminal apparatuses 130 are connected to the core network CN apparatus 120 through the radio access network RAN apparatus 110. Only two terminal devices 130, two RAN devices 110, one core network CN device 120 are schematically shown in fig. 1. The wireless communication system 100 may include more terminal devices, RAN devices, and CN devices. For example, one of the radio access network RAN apparatuses 110 shown in fig. 1 may serve two or more terminal apparatuses 130, and the CN apparatus 120 may be connected to more radio access network RAN apparatuses 110.

Terminal devices in embodiments of the present disclosure may include, but are not limited to, mobile Stations (MSs), mobile terminals (mobile terminals), mobile phones (mobile phones), user Equipment (UEs), handsets (handsets), portable devices (portable equipment), wireless communication enabled vehicles (vehicles), etc., which may communicate with one or more core networks via a radio access network (radio access network, RAN). For example, the terminal device may be a mobile phone (or "cellular" phone), a computer with wireless communication capabilities, or the like. In some embodiments, the terminal device may also be a portable, pocket, hand-held, computer-built-in or vehicle-mounted mobile device. Of course, the present disclosure may also include other types of terminal devices, which are not specifically limited by the present disclosure. In the embodiments of the present disclosure, the terminal device and the user equipment UE are used as equivalent concepts unless specifically stated.

The radio access network RAN device in the embodiments of the present disclosure is a device that provides communication in a wireless communication network to a terminal device, which may also be referred to as a base station. Depending on the communication protocol, the RAN device may include, but is not limited to, at least one of the following: a base transceiver station (base transceiver station, BTS), a Node B (Node B), an evolved Node B (eNB or e-NodeB), a new air interface NR or new Node B (generation Node B, gNB or g-NodeB), a Home base station (Home evolved Node B, home NodeB or HNB), a Base Band Unit (BBU), an Access Point (AP), etc. Of course, the RAN apparatus in the embodiments of the present disclosure may also include other types of RAN apparatuses, which are not specifically limited in this disclosure.

The core network CN device in the embodiment of the present disclosure is a gateway for managing terminal devices and providing communication with an external network. Optionally, in the 5G communication system, the core network CN device may include a mobility management function (access and mobility management function, AMF), which is mainly used for mobility management and access management, etc. In a 5G communication system, the AMF may be used to implement other functions than session management among mobility management entity (mobility management entity, MME) functions, such as lawful interception and access authorization/authentication. The core network device CN in the 5G communication network may also include other CN network elements including, but not limited to: session management functions (Session Management Function, SMF), user plane function entities (User Plane Function, UPF), unified Data management functions (Unified Data Management, UDM), authentication service functions (AUSF), policy control functions (Policy Control Function, PCF), network storage functions (NF Repository Function, NRF), application functions (Application Function, AF), network opening functions (Network Exposure Function, NEF), network slice selection functions (Network Slice Selection Function, NSSF), data Networks (DN), and the like. Of course, the wireless communication system of the present disclosure may also include communication networks employing other communication technologies, such as long term evolution (long term evolution, LTE), long term evolution-advanced (advanced long term evolution, LTE-a) systems, and the like. Accordingly, the CN device also includes CN network elements under other communication technologies, such as mobility management entities (Mobility Management Entity, MME) under LTE network architecture, which is of course not further limited by the present disclosure.

In this disclosure, both the RAN device and/or the CN device may be referred to as a network device that provides wireless communication services for the UE in the wireless communication network 100.

Conventionally, the wireless communication network 100 provides communication for terminal devices to core network CN devices based on a terrestrial network, also known as a public land mobile network (Public Land Mobile Network, PLMN). However, PLMN networks are facing more and more challenges, such as in areas of relatively complex topography, it is difficult to provide good communication services for terminal devices due to the difficulty in locating and installing base stations; for example, in urban environments, numerous buildings act as obstacles in wireless signal transmission, causing great attenuation to signal transmission, and especially for millimeter waves adopted in 5G communication systems, the problem is serious; as mentioned above, in a high-speed moving vehicle such as a high-speed rail, the mobile network needs to cover a large number of ground base stations to ensure the connection continuity of the terminal devices, which also causes a great cost.

For this purpose, the coverage of the radio access network is extended by introducing non-terrestrial entities in the communication path of the legacy terminal equipment to the core network as relay nodes between the terminal equipment to the core network. Such networks are also referred to as non-terrestrial network NTN systems with respect to PLMNs.

The wireless communication system 100 in the embodiments of the present disclosure may be adapted to PLMNs as well as NTNs. NTNs in the present disclosure include SAT communication systems, high altitude platform (High altitude platform station, HAPS) communication systems, or other non-terrestrial communication systems.

SAT communication systems are a common NTN system. Alternatively, the network device in the SAT communication system may be a geosynchronous orbit SAT (geostationary earth orbit, GEO) or a non-synchronized orbit SAT (non-geostationary earth orbit, NGEO). In addition, the ngao may be a high-orbit-SAT (HEO), a medium-orbit SAT (medium earth orbit, MEO), or a low-orbit SAT (LEO) according to the orbit height where the SAT providing the service is located, which is not limited in the present disclosure.

The SAT communications in the two scenarios are described below using fig. 2 and 3 as examples, respectively.

Scene 1: SAT access transparent forwarding mode

Fig. 2 illustrates a scenario in which a single SAT is used as transparent forwarding in an NTN system including a SAT communication system. As shown, only one SAT-1 exists in the communication link between the terminal device 130 and the base station 110, and the SAT-1 does not process the received information and only forwards it transparently. In scenario 1, where the base station 110 is still deployed on the ground, the terminal device 130 is in communication with the base station 110, and the signal is forwarded by the SAT-1, the SAT-1 does not process the received information, and the SAT-1 corresponds to a relay node or repeater, the scenario may be referred to as transparent load (transparent payload) mode. In the transparent load mode, SAT-1 only transparently forwards the received signal, and the forwarded signal is transmitted to core network 120 by the ground base station. In turn, information returned from core network 120 to terminal 130 is also transmitted to the terminal via transparent forwarding by SAT-1.

Scene 2: SAT access regeneration forwarding mode

Fig. 3 shows a scenario in which more than one SAT is used as regenerative forwarding in an NTN network comprising a SAT communication system. As shown, SAT-1 and SAT-2 each integrate all or part of the base station functionality and are connected to core network 120 through ground gateway 140. Unlike transparent forwarding mode, SAT-1 and/or SAT-2 herein may process received information. Optionally, these processes include, but are not limited to, operations performed by the original ground base station, such as encrypting, decrypting, populating, and/or changing information parameters, etc., for the received information. In addition, SAT-1 is a satellite connected to terminal 130, and SAT-2 is a satellite connected to the core network, as shown. Alternatively, in forwarding information from terminal 130, SAT-1 forwards the information to SAT-2, and SAT-2 forwards the information to the core network. Optionally, in the above information forwarding process, SAT-1 and/or SAT-2 may perform corresponding processing on the forwarded information. In turn, information transmitted back from core network 120 to terminal 130 is also forwarded to terminal 130 via SAT-2, SAT-1, where SAT-1 and/or SAT-2 may process the forwarded information accordingly. This SAT access regeneration forwarding mode shown in scenario 2 may also be referred to as a regeneration load (regenerative payload) mode.

Those skilled in the art will readily appreciate that FIG. 3 only schematically illustrates two satellites SAT-1 and SAT-2. Alternatively, two or more SATs may be included in the satellite access regenerative forwarding mode shown in fig. 3. For example, the information transmission path between SAT-1 and SAT-2 may also include one or more other satellites SAT-3, SAT-4, SAT-5 … … SAT-n, each of which may transparently forward and/or process received information. SAT-1 and SAT-2 may form one or more satellite transmission paths with at least one of one or more satellites SAT-3, SAT-4, SAT-5 … … SAT-n. For example, satellite transmission paths SAT path-1 include satellites SAT-1, SAT-3, SAT-2; the satellite transmission path SAT path-2 comprises satellites SAT-1, SAT-4 and SAT-2; the satellite transmission path SAT path-3 includes satellites SAT-1, SAT-3, SAT-4, SAT-2, etc. In this context, adjacent satellites in each satellite transmission path are connected by Inter-satellite Links (ISLs), each ISL corresponding to a satellite hop.

In fig. 3 described above, the packet delay between the terminal device and the core network becomes dynamic due to the introduction of ISL. The transmission delay of the link increases every more satellite hops, resulting in a further increase in the overall delay of the terminal device to the core network. Typical propagation delays caused by satellite forwarding in a satellite communication system in transparent forwarding mode are listed in table 1. It is to be understood that table 1 only lists typical satellite transmission delays, and this disclosure is not limited thereto.

Table 1: typical propagation delay by satellite forwarding in satellite communication systems

As shown in table 1, the service link (e.g., the terminal equipment 130 to SAT-1 in fig. 3) and the feeder link (e.g., the SAT-2 to the ground gateway 140 in fig. 3) inevitably incur long delays due to the long distance of the satellite from the ground, and such delays caused by satellite forwarding will be more significant in the regenerative forwarding mode. The satellite orbits and corresponding orbital heights included in a common satellite communications system are further detailed in table 2.

Table 2: common satellite orbits and corresponding orbital altitude ranges

Therefore, in the satellite forwarding scenario, transmission delay is a factor that affects communication quality and needs to be considered with emphasis. When a terminal device requests certain services, the services of the terminal device are often accompanied by certain delay requirements. This makes delay-sensitive traffic, such as V2X, generally not possible for certain traffic in scenarios involving satellite forwarding. Some services, even if they can be performed under conventional transparent satellite forwarding, may not meet the time delay requirement of the service due to extra time delay caused by the ISL after the ISL is added, so that the service experience is reduced or even cannot be continued. At present, before a specific service is initiated by a terminal device and a network, whether additional delay brought by an ISL can meet the requirement of the specific service on the delay is not considered, so that how to establish an effective service link in a satellite forwarding scene (such as the SAT access regeneration forwarding mode mentioned above) containing the ISL link is a technical problem to be solved.

According to embodiments of the present disclosure, a terminal device needs to first initiate a service setup request to a network device before performing certain services. In fig. 4, taking a flow of Packet Data Unit (PDU) session establishment in the 5G communication system as an example, a signaling procedure of initiating a target service by a terminal device is illustrated. However, those skilled in the art will readily appreciate that the present disclosure is not limited to 5G communication systems, and fig. 4 illustrates the inventive concepts of the present disclosure by way of example only. Specifically, as shown in the figure, the PDU session establishment procedure initiated by the UE includes the following procedures:

the UE sends PDU session establishment request information to the AMF, wherein the information comprises parameters such as session identification, session type, SCC mode, DNN, S-NSSAI and the like, and the PDU establishment request information is forwarded to the AMF through the base station.

AMF selects the appropriate SMF based on DNN, S-NSSAI and subscription data.

AMF invokes the session service of the selected SMF to trigger session establishment.

The smf obtains Session subscription data from the UDM, such as SCC mode allowed by the user, session type and Session-AMBR of the Session, etc.

Smf selects PCF and UPF for the session.

And 6, the SMF establishes policy connection with the PCF to acquire PCC rule.

The SMF invokes an N1/N2 messaging service to send session messages for the N1 and N2 interfaces to the AMF. Wherein the N1 message contains QoS parameters of QoS rule and QoS flow sent to the UE and the N2 message contains QoS profile sent to the base station.

The amf transmits the information obtained from the previous step to the base station through an N2 session request message.

9. And the base station establishes air interface resources according to the received parameters, and simultaneously, the base station transmits NAS information containing PDU session establishment acceptance to the UE.

10. The base station sends an N2 message reply to the AMF containing a list of QFI accepted by the base station and a list of QFI rejected.

AMF invokes session update service of SMF, and sends information obtained from base station to SMF.

The SMF distributes IPv6 address for the UE and sends the IPv6 address to the UE through a user plane.

In accordance with embodiments of the present disclosure, in an NTN system, the base station shown in fig. 4 may be replaced by a satellite base station (e.g., SAT-1, SAT-2, SAT-3, etc.). In the satellite access regeneration forwarding mode, PDU conversation request information initiated by the terminal equipment is required to be forwarded through the satellite base station, and after PDU conversation is established successfully, conversation data packets are required to be forwarded through the satellite base station. According to the embodiment of the disclosure, when the ISL time delay of satellite transmission and/or the additional time delay introduced by service link and feed link are large, the service experience of a user is reduced; or for delay sensitive traffic (e.g., V2X traffic), may cause related traffic to fail.

Referring now to fig. 5, shown therein is a schematic flow chart of a communication method in an NTN system including a SAT communication system, according to an embodiment of the present disclosure. In scenario 2, satellite SAT-1 may be connected to a terminal device, satellite SAT-2 may be connected to core network CN120, and SAT-1 may be connected to core network CN120 via SAT-2. Alternatively, there may be one or more other satellites SAT between SAT-1 and SAT-2, and SAT-1 may be connected to SAT-2 and in turn to core network CN120 via one or more of these satellites SAT.

Step S501: SAT-1 transmits the link delay information to terminal device 130 via a broadcast message.

Wherein the link delay information may indicate a link delay corresponding to at least one of the one or more satellite transmission paths from SAT-1 to SAT-2.

According to embodiments of the present disclosure, the link delay corresponding to the at least one satellite transmission path may include at least one of: a corresponding delay from the terminal device 130 to the service link of SAT-1; a link delay of the at least one satellite transmission path; and/or delay corresponding to the feeder link from the SAT-2 to the ground gateway.

According to embodiments of the present disclosure, SAT-1 may determine a link delay corresponding to at least one satellite transmission path according to preconfigured information. Alternatively, SAT-1 may be preconfigured with delay information of service link and/or feeder link, wherein the delay information of service link is different according to the terminal device 130 to which SAT-1 is connected, and the delay information of feeder link is different according to SAT-2 connected to the core network CN 120. Alternatively, SAT-1 can also determine the number of satellite hops it experiences to SAT-2, the satellites it experiences, and/or the total ISL delay it experiences from itself to SAT-2 through pre-configured information. Optionally, each satellite may be preconfigured with information indicating the number of satellite hops that the satellite needs to experience to the core network, the satellites that pass, and/or the total ISL delay that is to be experienced.

According to an embodiment of the present disclosure, the satellites to be experienced from SAT-1 to core network CN 120 only involve co-orbiting satellites, and the ISL delay corresponding to each satellite hop is a fixed value (typically, the ISL delay between two LEO satellites is typically 10ms, although other values are possible, and the present disclosure is not limited thereto). Therefore, SAT-1 may transmit only the information of the number of satellite hops from SAT-1 to SAT-2 to the terminal device 130 in a broadcast message.

According to embodiments of the present disclosure, the satellites to be experienced from SAT-1 to core network CN 120 are only related to satellites in orbit, but the ISL delay corresponding to each satellite hop is not a fixed value, or the satellites to be experienced from SAT-1 to core network CN 120 are related to satellites in different orbits, and the ISL delay corresponding to each satellite hop is not a fixed value. In the above case, SAT-1 may transmit delay information of a plurality of ISLs to the terminal device 130 in a broadcast message. Optionally, the delay information of the plurality of ISLs includes a delay corresponding to each ISL link or a total delay corresponding to the plurality of ISLs.

According to embodiments of the present disclosure, SAT-1 may be connected to SAT-2 and, in turn, to core network CN 130 via one or more satellite transmission paths. Alternatively, SAT-1 may transmit delay information corresponding to all possible satellite transmission paths to terminal device 130 via a broadcast message. Alternatively, SAT-1 may transmit delay information corresponding to a part of the satellite transmission path to terminal device 130 through a broadcast message. According to embodiments of the present disclosure, there are some satellite transmission paths between SAT-1 to SAT-2 that are preferably used to connect the terminal device 130 with the core network CN 120. These satellite transmission paths preferably used may be a satellite transmission path having the smallest number of satellite hops, a satellite transmission path having the smallest ISL delay, a satellite transmission path used more frequently, a satellite transmission path having the most robust signal transmission quality, and the like. Those skilled in the art will readily appreciate that these preferably used satellite transmission paths may also be classified satellite transmission paths that meet certain transmission conditions, which the present disclosure is not particularly limited to. According to the embodiment of the present disclosure, the satellite SAT-1 may transmit the delay information corresponding to the preferred satellite transmission path to the terminal device 130 through broadcasting information. According to embodiments of the present disclosure, SAT-1 may also broadcast delay information of a satellite transmission path corresponding to a maximum number of satellite hops or a maximum ISL delay to terminal device 130.

Step S502: the terminal device 130 determines whether the indicated link delay meets the delay requirement of the target service according to the link delay information received and sent by the SAT-1 broadcast.

According to an embodiment of the present disclosure, the terminal device 130 receives link delay information transmitted by SAT-1 through a broadcast message, which may be a system information block (System Information Block, SIB) message. The terminal device 130 determines whether the requirement of the target service to be initiated, such as a delay requirement, can be satisfied according to the received link delay information. If the requirements cannot be met, the terminal device 130 may choose not to initiate the establishment request of the target Service, i.e. not initiate a Service request or a PDU session establishment request for the target Service; if the requirements are met, the terminal device 130 may choose to initiate a set-up request for the target Service, i.e. initiate a Service request or a PDU session set-up request.

The terminal device 130 may also be connected to the core network CN 120 through other SATs according to embodiments of the present disclosure. Optionally, the terminal device 130 may also receive broadcasted link delay information from other SATs, where the link delay information indicates a link delay corresponding to the connection of the terminal device 130 to the core network CN 120 through the corresponding SAT, respectively. The terminal device 130 may select, according to the link delay information, a satellite link to access the core network CN 120 that meets the delay requirement of the target service. Optionally, when the terminal device 130 determines that the link delay information indicated by the SAT-1 does not meet the requirement of the target service, if there are other satellite SATs, the terminal device 130 may also learn that the satellite link delays corresponding to the other satellite SATs meet the requirement of the target service through a broadcast message, and the terminal device 130 may select the other satellite SATs to establish a connection.

Optionally, the terminal device 130 receives the link delay information broadcast by SAT-1, where the link delay information indicates a link delay of SAT-1 to SAT-2 as the minimum satellite hop count. Because the ISL delay corresponding to each satellite hop count is a fixed value, the terminal device 130 can determine the minimum satellite transmission delay that can be achieved by the satellite transmission paths from SAT-1 to SAT-2 according to the minimum satellite hop count. The terminal device 130 determines whether the minimum satellite transmission delay meets the delay requirement of the target service, specifically, whether the minimum satellite transmission delay meets the ISL delay requirement of the target service on satellite link transmission. If the delay requirement of the target service is met, for example, the minimum satellite transmission delay is less than or equal to the ISL delay requirement of the target service on the satellite link transmission, the terminal device 130 may initiate a service request or PDU session request for the target service. The minimum satellite link delay only ensures that SAT-1 can be transmitted through the satellite transmission path corresponding to the minimum ISL delay to meet the target service requirement.

Optionally, the terminal device 130 receives the link delay information broadcast by SAT-1, where the link delay information indicates a link delay of SAT-1 to SAT-2 as the maximum satellite hop count. Also, the terminal device may determine a maximum satellite transmission delay that may be achieved by the satellite transmission paths from SAT-1 to SAT-2 according to the maximum satellite hop count. If the maximum satellite transmission delay meets the delay requirement of the target service, specifically, if the maximum satellite transmission delay is less than or equal to the ISL delay requirement of the target service on the satellite link transmission, the terminal device 130 may initiate a service request or PDU session request for the target service. The maximum satellite link delay can ensure that SAT-1 can meet the target service requirement through any satellite transmission path transmission. The terminal device may be more robust in this case to initiate a service link or PDU session request for the target service, because once one of the satellite transmission paths becomes problematic, SAT-1 may quickly switch (e.g., blind switch) to the other satellite transmission path to continue transmitting the target service.

As described above, the link delay indicated by the link delay information of SAT-1 received by the terminal device may also be an ISL delay from SAT-1 to SAT-2, where the ISL delay may correspond to a minimum ISL delay of a satellite transmission path or a maximum ISL delay of a satellite transmission link, where the ISL delay refers to a total ISL delay of one or more ISL links included in the corresponding transmission path. Unlike the direct broadcast hop count information, the terminal device 130 does not need to further calculate the ISL latency of the satellite transmission path. In addition, the direct broadcast ISL link delay may be adapted to a case where the ISL link delay between adjacent satellites is fixed (e.g., co-orbiting satellites) or a case where the ISL link delay between adjacent satellites is different (e.g., non-orbiting satellites).

According to an embodiment of the present disclosure, the link delay indicated by the link delay information broadcast by SAT-1 received by the terminal device 130 may further include a service link delay and/or a feeder link delay. The terminal device 130 may determine whether the total delay including the ISL delay, the service link delay, and/or the feeder link delay generated by the satellite transmission path meets the requirements of the target service. Since the service link delay and/or feeder link generally do not change with the satellite transmission path, these information may be preconfigured in SAT-1 and/or terminal device 130, so that the link delay information sent by SAT-1 broadcasting may optionally indicate or not indicate the service link delay and/or feeder link delay. Alternatively, if the service link delay and/or the feeder link delay associated with SAT-1 are preconfigured in the terminal device 130, SAT-1 may choose not to carry both in the broadcast message to reduce the message size of the broadcast message.

According to embodiments of the present disclosure, the requirements, e.g., the latency requirements, of the target service to be initiated by the terminal device may include, for example, the latency requirements for the satellite transmission path or the total latency requirements including the service link and/or the feeder link in addition to the satellite transmission path.

Step S503: and sending a service request message for the target business.

If the terminal device 130 determines that the link delay indicated by the link delay information received from the SAT-1 meets the delay requirement of the target service, a service request for the target service is initiated. Optionally, the service request message is a non-access stratum NAS request message, where the NAS request message carries a service request or PDU session establishment request corresponding to the target service.

Fig. 6 shows a schematic flow chart of a communication method in an NTN system including a SAT communication system according to an embodiment of the present disclosure. Unlike the method shown in fig. 5, the terminal device 130 directly transmits the link delay information to the core network CN 120 after receiving the link delay information broadcasted by SAT-1.

Step S601: SAT-1 transmits the link delay information to terminal device 130 via a broadcast message.

In accordance with the foregoing, the link delay information may indicate a link delay corresponding to at least one of the one or more satellite transmission paths from SAT-1 to SAT-2.

Optionally, the link delay information includes satellite hop number information and/or ISL delay information corresponding to the at least one satellite transmission path. According to embodiments of the present disclosure, unless specifically stated otherwise, the ISL latency information or ISL latency may indicate or refer to a total latency corresponding to one or more ISLs included in the at least one satellite transmission path. The link delay information may carry hop count information and/or ISL delay information for the satellite, as shown by way of example in fig. 6, but the disclosure is not limited thereto. As an example, the link delay information may further include, but is not limited to, delay information corresponding to a service link from the terminal device 130 to the SAT-1 and/or delay information corresponding to a feeder link from the SAT-2 to the ground gateway. Optionally, the link delay information may include at least one of delay information corresponding to the service link and delay information corresponding to the feeder link, in addition to the satellite hop count information and/or ISL delay information. Optionally, the link latency information may include target latency information, wherein the target latency information indicates at least one of the following latency information: a time delay from the terminal device 130 to the SAT-2 via the SAT-1; a time delay from said SAT-1 to said SAT-2; a delay from the SAT-1 to the core network CN 120 via the SAT-2; time delay from the terminal device 130 to the core network CN 120 via at least one satellite transmission path between the SAT-1 and the SAT-2.

Step S602: the terminal device 130 transmits a service request message for the target service to the core network CN 120.

According to an embodiment of the disclosure, the service request message carries the link delay information.

According to the embodiment of the present disclosure, after receiving the link delay information sent by the SAT-1, the terminal device 130 does not determine whether the link delay indicated by the link delay information meets the requirement of the target service, but directly sends the link delay information to the core network CN 120. Optionally, the service request message is a non-access stratum NAS request message, and the NAS request message carries the link delay information. The NAS request message is forwarded to the core network CN120 via a satellite transmission path between SAT-1 and SAT-2.

Step S603: the core network CN120 determines whether the link delay indicated by the link delay information meets the delay requirement of the target service.

According to an embodiment of the present disclosure, the core network CN120 receives the service request message for the target service sent by the terminal device 130.

According to the embodiment of the present disclosure, the core network CN120 determines whether the requirement of the target service that the terminal device 130 wants to initiate, such as a delay requirement, can be met according to the link delay information. If the requirements cannot be met, the core network CN120 may not perform subsequent flow or send a rejection message to the terminal device 130; if the demand is met, the core network CN120 may proceed with subsequent flows including, for example, sending an accept message to the terminal device 130.

Optionally, the link delay information indicates a minimum satellite hop count of SAT-1 to SAT-2. Since the ISL delay corresponding to each satellite hop count is a fixed value, the core network CN120 may determine the minimum satellite transmission delay that may be achieved by the satellite transmission paths from SAT-1 to SAT-2 according to the minimum satellite hop count. The core network CN120 determines whether the minimum satellite transmission delay meets the delay requirement of the target service, specifically, whether the minimum satellite transmission delay meets the ISL delay requirement of the target service on satellite link transmission. If the delay requirement of the target service is met, for example, the minimum satellite transmission delay is less than or equal to the ISL delay requirement of the target service on the satellite link transmission, the core network CN120 may accept a service request or PDU session request for the target service initiated by the terminal device 130. The minimum satellite link delay only ensures that SAT-1 can be transmitted through the satellite transmission path corresponding to the minimum ISL delay to meet the target service requirement.

Optionally, the link delay information indicates a link delay of a maximum satellite hop count from SAT-1 to SAT-2. Also, the core network CN120 may determine the maximum satellite transmission delay that can be achieved by the satellite transmission paths from SAT-1 to SAT-2 according to the maximum satellite hop count. If the maximum satellite transmission delay meets the delay requirement of the target service, specifically, if the maximum satellite transmission delay is less than or equal to the ISL delay requirement of the target service on the satellite link transmission, the core network CN120 may accept a service request or PDU session request for the target service initiated by the terminal device 130. The maximum satellite link delay can ensure that SAT-1 can meet the target service requirement through any satellite transmission path transmission. The terminal device in this case may be more robust to initiate a service link or PDU session request for the target service, because once one of the satellite transmission paths has a problem, SAT-1 may quickly switch to the other satellite transmission path to continue transmitting the target service.

As described above, the link delay indicated by the link delay information may also be an ISL delay from SAT-1 to SAT-2, where the ISL delay may correspond to a minimum ISL delay of a satellite transmission path or a maximum ISL delay of a satellite transmission link, where the ISL delay refers to a total ISL delay of one or more ISL links included in the corresponding transmission path.

Optionally, the link delay indicated by the link delay information may further include a service link delay and/or a feeder link delay. The core network CN 120 may determine whether the total delay including the ISL delay, the service link delay, and/or the feeder link delay generated by the satellite transmission path meets the requirements of the target service.

Step S604: the core network CN 120 sends a service request accept/reject message to the terminal device 130.

According to the embodiment of the present disclosure, if the core network CN 120 determines that the delay requirement of the target service cannot be met, the core network CN 120 may not perform a subsequent flow or send a service request rejection message to the terminal device 130; if the core network CN 120 determines that the delay requirement of the target service can be met, the core network CN 120 may proceed with subsequent procedures including, for example, sending a service request accept message to the terminal device 130.

Fig. 7 shows a schematic flow chart of a communication method in an NTN system including a SAT communication system according to an embodiment of the present disclosure.

Step S701: the terminal device 130 transmits a service request message for the target traffic.

Optionally, the service request message is a NAS message, where the NAS request message carries a service request or PDU session establishment request corresponding to the target service. The NAS request message is forwarded to the core network CN 120 via the first satellite transmission path of SAT-1 to SAT-2.

Step S702: SAT-2 sends the link delay information experienced by the service request message to the core network CN 120.

The link delay information indicates a link delay corresponding to a first satellite transmission path from SAT-1 to SAT-2 for forwarding the service request message.

According to an embodiment of the present disclosure, SAT-2 is a satellite connected to the core network CN 120. A service request message, e.g. NAS request message, from the terminal device 130 needs to last go through SAT-2 before being forwarded to the core network CN 120 via the satellite network. Before forwarding the NAS request message to the core network CN 120, the SAT-2 determines, according to the preconfigured information, a link delay corresponding to a first satellite transmission path that the NAS request message is forwarded to the SAT-2. In an embodiment according to the present disclosure, the pre-configuration information includes at least one of: the number of satellite hops corresponding to one or more satellite transmission paths from said SAT-1 to said SAT-2; ISL time delay corresponding to one or more satellite transmission paths from the SAT-1 to the SAT-2; and one or more SATs corresponding to one or more satellite transmission paths from the SAT-1 to the SAT-2. SAT-2 determines a link delay corresponding to the first satellite transmission path based on the pre-configuration information.

According to an embodiment of the disclosure, the link delay corresponding to the first satellite transmission path at least includes information of a number of satellite hops and/or ISL delay information included in the first satellite transmission path. Optionally, the link delay corresponding to the first satellite transmission path further includes a service link delay corresponding to SAT-1 and/or a feeder link delay via SAT-2.

According to an embodiment of the present disclosure, SAT-2 includes the service request message and the link delay information it experiences in an N2 message and forwards it to the core network CN 120.

Step S703: the core network CN120 determines whether the link delay indicated by the link delay information meets the delay requirement of the target service.

According to an embodiment of the present disclosure, the core network CN120 receives an N2 message sent by the SAT-2, where the N2 message includes a service request message for the target service and link delay information. Optionally, the service request message for the target service includes a NAS request message.

According to the embodiment of the present disclosure, the core network CN120 determines whether the requirement of the target service that the terminal device 130 wants to initiate, such as a delay requirement, can be met according to the link delay information. Step S704: the core network CN120 sends a service request accept/reject message to the terminal device 130.

Fig. 8 shows a schematic flow chart of a communication method in an NTN system including a SAT communication system according to an embodiment of the present disclosure.

Step S801: the terminal device 130 transmits a service request message for the target traffic.

Optionally, the service request message may be a NAS request message, where the NAS request message carries a service request or PDU session establishment request corresponding to the target service.

Step S802: SAT-1 determines an allowable link latency threshold.

According to embodiments of the present disclosure, SAT-1 determines the allowed link latency threshold based on the requirements of the target traffic, e.g., latency requirements. Fig. 8 shows by way of example that the allowed link latency threshold may include, but is not limited to, the number of allowed satellite hops and/or ISL latency.

According to embodiments of the present disclosure, SAT-1 may be preconfigured with a mapping of service latency requirements to the number of satellite hops and/or ISL latency. The SAT-1 may determine, according to the mapping relationship, the number of satellite hops allowed by the target service and/or an ISL delay, where the allowed ISL delay refers to a total ISL delay corresponding to one or more ISLs included in the satellite transmission path.

Optionally, in determining the allowed link delay threshold, the SAT-1 may also consider a delay corresponding to a service link from the terminal device 130 to the SAT-1 and/or a delay corresponding to a feeder link from the SAT-2 to the core network CN 120. For example, SAT-1 may determine the number of satellite hops and/or ISL latency allowed by the latency requirement of the target service, taking into account the latency corresponding to the service link and/or the latency corresponding to the feeder link.

Step S803: SAT-1 forwards a service request message for a target service, with an allowable link delay threshold added to the header of the forwarded message.

Optionally, the allowed link delay threshold includes a number of satellite hops allowed by the target service and/or an ISL delay.

Optionally, the forwarded message (e.g., message header) also includes a link delay experienced by the service request message. According to an embodiment of the disclosure, the SAT-1 may set the link delay experienced by the service request message as a link transmission delay, for example, a delay corresponding to a service link; or set to an ISL latency currently experienced by the service request message, e.g., zero or null; or set to the number of satellite hops currently experienced by the service request message, e.g., zero or null; or set to an ISL delay that the service request message will experience, e.g., an ISL-corresponding delay between the SAT-1 and the next satellite; or to the number of satellite hops that the service request message will experience, e.g. 1.

Step S804: SAT-n judges whether or not the condition for continuing forwarding is satisfied

Optionally, the SAT-n determining whether the forwarding continuation condition is satisfied includes: it is determined whether the number of satellite hops and/or ISL latency experienced by the forwarded service request message exceeds the number of allowed satellite hops and/or the allowed ISL latency.

Wherein SAT-n is the SAT involved in one or more satellite transmission paths between SAT-1 and the core network CN 120, where n may be 2, 3, 4, 5, … …, the numbering being merely for distinguishing SAT-n from SAT-1. Specifically, the SAT-n may be the SAT-2 mentioned above connected to the core network CN 120, or the SAT connected to the core network CN 120 via one or more other SATs, for example, the SAT-n may be the SAT involved in one or more satellite transmission paths between the SAT-1 and the SAT-2, such as the SAT-n may be the SAT-3, the SA-4, the SA-5, etc. mentioned above.

For simplicity, one SAT-n is schematically illustrated in FIG. 8. However, it will be readily appreciated by those skilled in the art that one or more other SATs may also be involved in the satellite regenerative forwarding process shown in fig. 8, i.e. SAT-n may receive messages forwarded by one or more other SATs, and may also forward messages to one or more other SATs or to the core network CN 120.

Taking a SAT-n as an example, it is specifically described how the SAT-n determines whether the number of satellite hops and/or the ISL delay experienced by the forwarded service request message of the terminal device 130 exceeds the number of allowed satellite hops and/or the allowed ISL delay.

According to an embodiment of the present disclosure, satellite SAT-n receives a forwarded message, which may include a service request message of terminal device 130 and an allowed link delay threshold. Optionally, the forwarded message may further include a link delay that the service request message experiences.

Optionally, the allowed link latency threshold may indicate a number of satellite hops allowed by a latency requirement corresponding to the target service. Alternatively, the link delay experienced by the service request message may indicate the number of satellite hops experienced by the service request message.

Optionally, the number of satellite hops the service request of the terminal device 130 experiences is the number N1 of satellite hops the service request experiences before reaching SAT-N. Optionally, the number of satellite hops undergone by the service request of the terminal device 130 is the number N2 of satellite hops undergone by the service request after reaching SAT-N. For example, when the service request is forwarded directly from SAT-1 to SAT-N, N1 equals 0 or N2 equals 1; when the service request is forwarded from SAT-1 to SAT-N through a satellite, N1 equals 1 or N2 equals 2; when the service request goes through two satellites from SAT-1 to be forwarded to SAT-N, N1 equals 2 or N2 equals 3, and so on.

According to embodiments of the present disclosure, N1 or N2 may be included in the forwarded message. In other words, SAT-n may read the number of satellite hops that the service request message experiences directly from the received forward message. When the read N1 or N2 exceeds the number of satellite hops allowed by the latency requirement of the target service, SAT-N may decide not to continue forwarding the service request. When the read N1 or N2 does not exceed the number of satellite hops allowed by the latency requirement of the target service, SAT-N may decide to continue forwarding the service request.

According to an embodiment of the present disclosure, when SAT-N decides to continue forwarding the service request, N1 or N2 may be updated, and the updated N1 or N2 may be stored in a message to be forwarded, and then sent on to the next satellite (SAT-N is not connected to the core network) or the core network CN 120 (SAT-N is connected to the core network, e.g. SAT-N is SAT-2 above). According to an embodiment of the disclosure, the SAT-N may replace the original N1 or N2 in the message to be forwarded with the updated N1 or N2, and perform the subsequent forwarding steps.

Optionally, the allowed link delay threshold may indicate an ISL delay allowed by a delay requirement corresponding to the target service. Alternatively, the link latency experienced by the service request message may indicate one or more ISL latencies corresponding to the ISL experienced by the service request message.

Optionally, the delay corresponding to one or more ISLs experienced by the service request of the terminal device 130 is the total delay t1 of one or more ISLs experienced before the service request arrives at SAT-n; or the total delay t2 of one or more ISLs after the service request reaches SAT-n.

According to embodiments of the present disclosure, t1 or t2 may be included in the forwarded message. In other words, SAT-n directly reads the ISL latency experienced by the service request message from the received forward message. When the read t1 or t2 exceeds the ISL delay allowed by the delay requirement of the target service, the SAT-n may decide not to continue forwarding the service request. When the read t1 or t2 does not exceed the ISL delay allowed by the delay requirement of the target service, SAT-n may decide to continue forwarding the service request.

According to an embodiment of the present disclosure, when SAT-n decides to continue forwarding the service request, t1 or t2 may be updated, and the updated t1 or t2 may be stored in a message to be forwarded, and then sent on to the next satellite (SAT-n is not connected to the core network) or to the core network CN 120 (SAT-n is connected to the core network, e.g. SAT-n is SAT-2 above). According to an embodiment of the disclosure, the SAT-n may replace the original t1 or t2 in the message to be forwarded with the updated t1 or t2, and perform the subsequent forwarding steps.

According to the embodiment of the disclosure, SAT-n determines, according to the correspondence between the preconfigured ISL delay and the satellite ID, a first ISL delay corresponding to a first ISL link that receives a forwarded message, where the forwarded message includes the service request of the terminal device 130. SAT-n adds the first ISL delay to t1 and saves the updated t1 in the message to be forwarded.

According to the embodiment of the disclosure, SAT-n determines a second ISL delay corresponding to a second ISL link to be used for forwarding the service request according to the corresponding relation between the preconfigured ISL delay and the satellite ID. SAT-n adds the second ISL delay to t2 and saves the updated t2 in the message to be forwarded.

It should be understood that the ISL delay indicated in the correspondence between ISL delays and satellite IDs is the delay corresponding to ISL between the SAT-n and the satellite indicated by the corresponding satellite ID. Table 3 shows the correspondence of ISL latency to satellite ID pre-configured at SAT-n, according to an embodiment of the present disclosure. As will be readily appreciated by those skilled in the art, SAT-a, SAT-b, SAT-c are shown in Table 3 for purposes of illustration only as satellites having a connection relationship with SAT-n, and are not intended to limit the connection of SAT-n to only such satellites. X1, X2, X3 shown in table 3 represent different ISL latency values, which may be the same or different. Alternatively, as examples, the X1, X2, X3 may be 7, 8, 9 or 5, 7, which is not limited by the present disclosure.

Table 3: ISL time delay mapping table preconfigured at SAT-n

Step S805: SAT-n continues to forward the service request of terminal device 130.

According to an embodiment of the present disclosure, if SAT-n determines that the condition for continuing forwarding is satisfied, step S805 is performed; otherwise, step S805 is not performed.

Optionally, the SAT-n is SAT-2 connected to the core network CN 120. In case the SAT-N determines that the service request of the forwarding continuation terminal device 130 is fulfilled, the SAT-N may forward the service request message to the core network CN 120 via an N2 message.

Optionally, the SAT-n is the SAT involved in one or more satellite transmission paths between SAT-1 and SAT-2. In case the SAT-n determines that the service request of the continuing forwarding terminal device 130 is fulfilled, the SAT-n may forward the service request message to the next regenerative forwarding SAT.

Fig. 9 shows a schematic flow chart of a communication method in an NTN system including a SAT communication system according to an embodiment of the present disclosure.

Step S901: the terminal device 130 transmits a service request message for the target traffic.

Alternatively, the service request message may carry the time T1 at which the service request message is sent. Optionally, the time T1 is a local time when the terminal device 130 sends the service request message.

Optionally, the service request message may be a NAS request message, where the NAS request message carries a service request or PDU session establishment request corresponding to the target service. The NAS request message may include a local time T1 at which the terminal apparatus 130 transmits the NAS request message.

Alternatively, the service request message may include a NAS request message for the target service and a local time T1 for transmitting the NAS request message.

Step S902: SAT-1 determines whether a forwarding condition (optional) is satisfied.

According to an embodiment of the present disclosure, after the SAT-1 receives the service request message, it is determined whether a condition for forwarding the service request message is satisfied. If so, the step jumps to S903; if not, the service request message is not forwarded and steps S902-S905 need not be performed.

Optionally, the SAT-1 determines, according to the preconfigured information, a link delay corresponding to a service link between the terminal device 130 and the SAT-1 and/or a link delay corresponding to a transmission link of the SAT-1 to the core network via one or more SATs. The SAT-1 determining whether a condition for forwarding the service request message is satisfied includes: determining whether the link delay corresponding to the service link and/or the link delay corresponding to the transmission link from the SAT-1 to the core network through one or more SATs meet the delay requirement of the target service.

Optionally, the service request message carries a time T1 for sending the service request message. The SAT-1 determining whether a condition for forwarding the service request message is satisfied includes: determining a time T2 when the service request message is received; determining a link delay experienced by the service request message transmitted to the SAT-1 based on a difference between the time T2 and the time T1; it is determined whether the experienced link delay meets the delay requirement of the target service.

According to the embodiment of the present disclosure, step S902 is optional, and SAT-1 may directly jump to step S903 without performing step S902, i.e., SAT-1 does not make a decision as to whether to forward the service request message, and directly forwards the service request message to the next satellite.

Step S903: SAT-1 receives the service request message and forwards it to the next satellite SAT-n.

Step S904: SAT-n determines whether the condition for continuing forwarding is satisfied.

According to an embodiment of the present disclosure, the service request message may carry a time T1 at which the service request message is transmitted. Optionally, the time T1 is a local time when the terminal device 130 sends the service request message. Optionally, the SAT-n determining whether the condition for continuing forwarding is satisfied includes: SAT-n determines a time T2 at which the forwarded service request message is received; based on the time T1 in the service request message and the determined time T2, it is determined whether the link delay experienced by the transmission of the service request message to the SAT-n exceeds the delay requirement of the target service. Optionally, the time T2 is a local time when the SAT-n receives the forwarded service request message.

As described above, SAT-n is a SAT involved in one or more satellite transmission paths between SAT-1 and the core network CN 120, and will not be described in detail herein.

According to embodiments of the present disclosure, SAT-n may determine the local time T2 upon receipt of the forwarded service request message. SAT-n may read from the forwarded service request message the local time T1 when the terminal device 130 sent the service request message. Based on the time difference between T2 and T1, SAT-n can calculate the link delay experienced by forwarding the service request message, and then judge whether the link delay meets the delay requirement of the target service. According to an embodiment of the present disclosure, when the link delay exceeds the delay requirement of the target service, SAT-n may not forward the service request message; when the link delay does not exceed the delay requirement of the target service, the SAT-n may continue forwarding the service request message.

Step S905: SAT-n continues to forward the service request message of terminal device 130.

According to an embodiment of the present disclosure, if SAT-n determines that the condition for continuing forwarding the service request message is satisfied, step S905 may be performed; otherwise, step S905 may not be performed.

Fig. 10 shows a schematic flow chart of a communication method in an NTN system including a SAT communication system according to an embodiment of the present disclosure. Unlike the situation shown in fig. 8 and 9, in which the satellites responsible for forwarding all determine whether the delay experienced by the service request of the forwarding terminal device 130 exceeds the delay requirement of the target service, fig. 10 shows a simpler situation in which only the satellite SAT-2 that is last connected to the core network CN 120 determines whether the delay experienced by the service request of the terminal device 130 forwarded to the SAT-2 exceeds the delay requirement of the target service, and further decides whether to forward the service request to the core network CN 120.

Step S1001: the terminal device 130 transmits a service request message for the target traffic.

Step S1002: SAT-1 determines the corresponding delay from terminal device 130 to the service link of SAT-1.

Optionally, when the SAT-1 receives the service request message, a delay corresponding to the service link may be determined according to preconfigured information.

Step S1003: and the SAT-1 forwards the time delay corresponding to the service link and the service request to the SAT-2 together in a message to be forwarded.

Alternatively, SAT-1 may forward the message to be forwarded directly to SAT-2, or via one or more other satellites to SAT-2, where SAT-2 is connected to core network CN 120. Fig. 9 illustrates, as an example, only a case of direct forwarding between SAT-1 to SAT-2, but the present disclosure is not limited thereto.

Step S1004: SAT-2 determines whether a condition for continuing forwarding is satisfied

According to the embodiment of the disclosure, after the SAT-2 receives the forwarded message, the link delay experienced by the service request transmitted from the terminal device 130 to the SAT-2 may be calculated according to the delay corresponding to the service link included in the forwarded message and determining the ISL total delay from the SAT-1 to the SAT-2 according to the preconfigured information. When the calculated link delay cannot meet the delay requirement of the target service, SAT-2 may not continue to forward the service request message to the core network CN 120. When the calculated link delay can meet the delay requirement of the target service, SAT-2 may forward the service request message to the core network CN 120. Alternatively, SAT-2 forwards the calculated link delay along with the service request message to the core network CN 120.

Step S1005: SAT-2 forwards the service request to the core network CN 120.

According to an embodiment of the present disclosure, if SAT-2 determines that the continue forwarding condition is satisfied, step S1005 may be performed; otherwise, step S1005 may not be performed. According to an embodiment of the present disclosure, SAT-2 may forward the service request message to the core network CN 120 through an N2 message.

Fig. 11 is a schematic flow diagram of a communication method performed by a SAT according to an embodiment of the present disclosure. According to an embodiment of the present disclosure, in an NTN system including a SAT communication system, the NTN provides communication with a network device (e.g., UE) for a terminal device through a plurality of satellite SATs. The plurality of SATs includes a first SAT (e.g., SAT-1 described above) coupled to the UE. The plurality of SATs further includes a second SAT (e.g., SAT-2 described above) coupled to the network device. One or more satellite transmission paths exist between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected through inter-satellite links (ISLs), and each ISL corresponds to one satellite jump. Messages from the terminal device/to the network device are forwarded/sent to the network device via one or more satellite transmission paths between the first SAT and the second SAT. Messages from/to the network device are forwarded/sent to the terminal device via one or more satellite transmission paths between the first SAT and the second SAT.

According to an embodiment of the disclosure, the first SAT may send link delay information to the UE, as shown in block 1101, wherein the link delay information indicates a delay corresponding to at least one of the one or more satellite transmission paths.

Optionally, the delay corresponding to the at least one of the one or more satellite transmission paths includes: a first delay of at least one of the one or more satellite transmission paths from the first SAT to the second SAT. Optionally, the delay corresponding to the at least one of the one or more satellite transmission paths further comprises: a second delay from the UE to the first SAT; and a third delay from the second SAT to the network device.

Fig. 12 is a schematic flow diagram of a communication method performed by a terminal device according to an embodiment of the present disclosure. According to an embodiment of the present disclosure, in an NTN system including a SAT communication system, the NTN provides communication with a network device (e.g., UE) for a terminal device through a plurality of satellite SATs. The plurality of SATs includes a first SAT (e.g., SAT-1 described above) coupled to the UE. The plurality of SATs further includes a second SAT (e.g., SAT-2 described above) coupled to the network device. One or more satellite transmission paths exist between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected through inter-satellite links (ISLs), and each ISL corresponds to one satellite jump. Messages from the terminal device/to the network device are forwarded/sent to the network device via one or more satellite transmission paths between the first SAT and the second SAT. Messages from/to the network device are forwarded/sent to the terminal device via one or more satellite transmission paths between the first SAT and the second SAT.

According to an embodiment of the present disclosure, as shown in block 1201, the UE receives link delay information sent by a first SAT of the plurality of SATs, wherein the link delay information indicates a link delay corresponding to at least one satellite transmission path of the one or more satellite transmission paths.

According to an embodiment of the disclosure, as shown in block 1202, the UE determines whether to initiate a NAS request message for a target service according to the link latency information.

Optionally, the link delay corresponding to the at least one of the one or more satellite transmission paths includes: a first delay of at least one of the one or more satellite transmission paths from the first SAT to the second SAT.

Optionally, the link delay corresponding to the at least one of the one or more satellite transmission paths further comprises at least one of: a second delay from the UE to the first SAT; and a third delay from the second SAT to the network device.

Fig. 13 is a schematic flow diagram of a communication method performed by a terminal device according to an embodiment of the disclosure. According to an embodiment of the present disclosure, in an NTN system including a SAT communication system, the NTN provides communication with a network device (e.g., UE) for a terminal device through a plurality of satellite SATs. The plurality of SATs includes a first SAT (e.g., SAT-1 described above) coupled to the UE. The plurality of SATs further includes a second SAT (e.g., SAT-2 described above) coupled to the network device. One or more satellite transmission paths exist between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected through inter-satellite links (ISLs), and each ISL corresponds to one satellite jump. Messages from the terminal device/to the network device are forwarded/sent to the network device via one or more satellite transmission paths between the first SAT and the second SAT. Messages from/to the network device are forwarded/sent to the terminal device via one or more satellite transmission paths between the first SAT and the second SAT.

According to an embodiment of the present disclosure, as shown in block 1301, the UE receives link delay information sent by a first SAT of the plurality of SATs, wherein the link delay information indicates a link delay corresponding to at least one satellite transmission path of the one or more satellite transmission paths.

According to an embodiment of the present disclosure, as shown in block 1302, the UE sends a NAS request message for a target service, where the NAS request message includes the link delay information.

Fig. 14 is a schematic flow diagram of a communication method performed by a SAT in accordance with an embodiment of the present disclosure. According to an embodiment of the present disclosure, in an NTN system including a SAT communication system, the NTN provides communication with a network device (e.g., UE) for a terminal device through a plurality of satellite SATs. The plurality of SATs includes a first SAT (e.g., SAT-1 described above) coupled to the UE. The plurality of SATs further includes a second SAT (e.g., SAT-2 described above) coupled to the network device. One or more satellite transmission paths exist between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected through inter-satellite links (ISLs), and each ISL corresponds to one satellite jump. Messages from the terminal device/to the network device are forwarded/sent to the network device via one or more satellite transmission paths between the first SAT and the second SAT. Messages from/to the network device are forwarded/sent to the terminal device via one or more satellite transmission paths between the first SAT and the second SAT.

According to an embodiment of the present disclosure, the second SAT sends a first message to the network device, as shown in block 1401, wherein the first message comprises a NAS request message for a target service and the first message comprises link latency information. According to an embodiment of the disclosure, the second SAT may receive the NAS request message before sending the first message to the network device, where the NAS request message is transmitted to the second SAT via a first satellite transmission path of the one or more satellite transmission paths, and the link delay information indicates a link delay corresponding to the first satellite transmission path.

Optionally, the link delay corresponding to the first satellite transmission path includes: a first delay of at least one of the one or more satellite transmission paths from the first SAT to the second SAT.

Optionally, the link delay corresponding to the first satellite transmission path further includes at least one of: a second delay from the UE to the first SAT; and a third delay from the second SAT to the network device.

Fig. 15 is a schematic flow diagram of a communication method performed by a network device according to an embodiment of the present disclosure. According to an embodiment of the present disclosure, in an NTN system including a SAT communication system, the NTN provides communication with a network device (e.g., UE) for a terminal device through a plurality of satellite SATs. The plurality of SATs includes a first SAT (e.g., SAT-1 described above) coupled to the UE. The plurality of SATs further includes a second SAT (e.g., SAT-2 described above) coupled to the network device. One or more satellite transmission paths exist between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected through inter-satellite links (ISLs), and each ISL corresponds to one satellite jump. Messages from the terminal device/to the network device are forwarded/sent to the network device via one or more satellite transmission paths between the first SAT and the second SAT. Messages from/to the network device are forwarded/sent to the terminal device via one or more satellite transmission paths between the first SAT and the second SAT.

According to an embodiment of the present disclosure, as shown in block 1501, the network device may receive a first message from a second SAT of the plurality of SATs, the first message being for requesting a service corresponding to a target traffic, and the first message including link delay information.

According to embodiments of the present disclosure, the network device may determine whether to accept the NAS request for the target service based on the link latency information, as shown in block 1502.

Optionally, the link delay information indicates a link delay corresponding to at least one of the one or more satellite transmission paths.

Optionally, the network device is a core network device. Optionally, the core network device is a mobility management entity MME or an access management function AMF.

Fig. 16 is a schematic flow diagram of a communication method performed by a SAT according to an embodiment of the present disclosure. According to an embodiment of the present disclosure, in an NTN system including a SAT communication system, the NTN provides communication with a network device (e.g., UE) for a terminal device through a plurality of satellite SATs. The plurality of SATs includes a first SAT (e.g., SAT-1 described above) coupled to the UE. The plurality of SATs further includes a second SAT (e.g., SAT-2 described above) coupled to the network device. One or more satellite transmission paths exist between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected through inter-satellite links (ISLs), and each ISL corresponds to one satellite jump. Messages from the terminal device/to the network device are forwarded/sent to the network device via one or more satellite transmission paths between the first SAT and the second SAT. Messages from/to the network device are forwarded/sent to the terminal device via one or more satellite transmission paths between the first SAT and the second SAT.

According to an embodiment of the disclosure, the first SAT may receive a NAS request message for a target service from the UE, as shown in block 1601. According to an embodiment of the present disclosure, the first SAT may determine a satellite transmission path delay threshold allowed by a delay requirement of the target service, as shown in block 1602. According to an embodiment of the disclosure, the first SAT may send a first message, as shown in block 1603, wherein the first message may include the allowed satellite transmission path delay threshold and the NAS request message.

Optionally, the allowed satellite transmission path delay threshold may include a threshold number of allowed satellite hops and/or an allowed ISL delay threshold.

Fig. 17 is a schematic flow diagram of a communication method performed by a SAT according to an embodiment of the present disclosure. According to an embodiment of the present disclosure, in an NTN system including a SAT communication system, the NTN provides communication with a network device (e.g., UE) for a terminal device through a plurality of satellite SATs. The plurality of SATs includes a first SAT (e.g., SAT-1 described above) coupled to the UE. The plurality of SATs further includes a second SAT (e.g., SAT-2 described above) coupled to the network device. One or more satellite transmission paths exist between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected through inter-satellite links (ISLs), and each ISL corresponds to one satellite jump. Messages from the terminal device/to the network device are forwarded/sent to the network device via one or more satellite transmission paths between the first SAT and the second SAT. Messages from/to the network device are forwarded/sent to the terminal device via one or more satellite transmission paths between the first SAT and the second SAT.

According to embodiments of the present disclosure, one or more satellite transmission paths between the first SAT and the second SAT include one or more third SATs therein. Alternatively, the third SAT may be the first SAT. Alternatively, the third SAT may be the second SAT. Optionally, the third SAT is another SAT included in a satellite transmission path between the first SAT and the second SAT. It will be readily apparent to those skilled in the art that the "third SAT" is merely to be expressed as being distinct from the "first SAT" and the "second SAT", and does not necessarily refer to another SAT different from the first SAT and the second SAT.

According to an embodiment of the disclosure, the third SAT may receive a first message requesting a service corresponding to the target business, as shown in block 1701. According to an embodiment of the present disclosure, the third SAT may determine link latency information, as indicated in block 1702. According to an embodiment of the disclosure, the third SAT may determine whether to forward the first message based on the link latency information, as in block 1703.

Optionally, the third SAT may determine whether the link delay indicated by the link delay information meets the delay requirement of the target service; forwarding the first message under the condition that the indicated link delay meets the delay requirement of the target service; and/or not forwarding the first message in case the indicated link delay does not meet the delay requirement of the target service.

Optionally, the indicated link delay may include a first link delay of at least one of the one or more satellite transmission paths.

Optionally, the indicated link delay further comprises at least one of: a second link delay of the UE to the first SAT; and a third link delay of the second SAT to the network device.

Fig. 18 is a schematic block diagram of a terminal device 1800 according to an embodiment of the disclosure. The terminal device may be the user equipment UE mentioned above. The terminal device 1800 includes at least a receiving unit 1801, a transmitting unit 1802. According to an embodiment of the present disclosure, the receiving unit 1801 and the transmitting unit 1802 may be integrated together as a transceiving unit. Optionally, the terminal device further comprises a determining unit 1803.

According to an embodiment of the present disclosure, the terminal device 1800 may perform a method according to the third aspect of the present disclosure. As shown in fig. 18, the terminal device 1800 includes a receiving unit 1801, where the receiving unit 1801 may be configured to receive link delay information sent by a first SAT of the plurality of SATs, where the link delay information indicates a link delay corresponding to at least one satellite transmission path of the one or more satellite transmission paths. According to an embodiment of the present disclosure, the terminal device 1800 may further comprise a determining unit 1803, where the determining unit 1803 is configured to determine whether to initiate a non-access stratum NAS request message for a target service according to the link latency information.

Optionally, the link delay information includes: number of satellite hops information; or ISL latency information.

Optionally, the at least one satellite transmission path of the one or more satellite transmission paths includes: at least one satellite transmission path between the first SAT and the second SAT through which messages are transmitted.

Optionally, the at least one satellite transmission path of the one or more satellite transmission paths includes: a satellite transmission path corresponding to a minimum number of satellite hops or a maximum number of satellite hops among the one or more satellite transmission paths.

Optionally, the link delay information is information of a number of satellite hops, and the information of the number of satellite hops indicates a number of satellite hops included in a satellite transmission path corresponding to a minimum number of satellite hops or a maximum number of satellite hops in the one or more satellite transmission paths.

Optionally, the ISL delay corresponding to each satellite hop is the same.

Optionally, the at least one satellite transmission path of the one or more satellite transmission paths includes: and the one or more satellite transmission paths correspond to the satellite transmission path with the minimum ISL delay or the maximum ISL delay.

Optionally, the link delay information is ISL delay information, where the ISL delay information indicates an ISL delay corresponding to a satellite transmission path corresponding to a minimum ISL delay or a maximum ISL delay in the one or more satellite transmission paths.

Optionally, the receiving unit 1801 is configured to receive a first broadcast message sent by the first SAT, where the first broadcast message includes the link delay information.

Optionally, the broadcast message is a system information block SIB message.

Alternatively, the determining unit 1803 is configured to: determining whether the link delay indicated by the link delay information meets the delay requirement of the target service; under the condition that the link delay indicated by the link delay information meets the delay requirement of the target service, initiating a NAS request message aiming at the target service; and/or under the condition that the link delay indicated by the link delay information does not meet the delay requirement of the target service, not initiating the NAS request message aiming at the target service.

Optionally, the NAS request message includes a service request for the target service or a PDU session establishment request for the target service.

Optionally, the network device is a core network element.

Optionally, the core network element is a mobility management function AMF.

According to an embodiment of the present disclosure, the terminal device 1800 may perform a method according to the fourth aspect of the present disclosure. As shown in fig. 18, the terminal device 1800 may include a receiving unit 1801, where the receiving unit 1801 may be configured to receive link delay information sent by a first SAT of the plurality of SATs, where the link delay information indicates a link delay corresponding to at least one satellite transmission path of the one or more satellite transmission paths. As shown in fig. 18, the terminal device 1800 may include a transmitting unit 1802, and the transmitting unit 1802 may be configured to transmit a non-access stratum NAS request message for a target service, where the NAS request message includes the link delay information.

Optionally, the ISL delay corresponding to each satellite hop is the same.

Optionally, the broadcast message is a system information block SIB message.

Optionally, the NAS request message includes a service request for the target service or a PDU session establishment request for the target service. Optionally, the network device is a core network element.

Optionally, the core network element is a mobility management function AMF.

Fig. 19 is a schematic block diagram of a satellite 1900 according to an embodiment of the disclosure. As shown in fig. 19, the satellite 1900 includes at least a receiving unit 1901 and a transmitting unit 1902. According to an embodiment of the present disclosure, the receiving unit 1901 and the transmitting unit 1902 may be integrated together as a transceiving unit. Optionally, the satellite 1900 further comprises a determining unit 1903, an updating unit 1904.

According to an embodiment of the present disclosure, the satellite 1900 may perform the method according to the first aspect of the present disclosure. As shown in fig. 19, the satellite 1900 may include a receiving unit 1901, and the receiving unit 1901 may be configured to transmit link delay information to the UE, wherein the link delay information indicates a link delay corresponding to at least one of the one or more satellite transmission paths.

Optionally, the satellite 1900 further comprises a determining unit 1903, the determining unit 1903 being configured to determine the link delay information from preconfigured information.

Optionally, the ISL delay corresponding to each satellite hop is the same.

Optionally, the preconfigured information includes at least one of: the number of satellite hops corresponding to one or more satellite transmission paths from the first SAT to the second SAT; ISL time delay corresponding to one or more satellite transmission paths from the first SAT to the second SAT; one or more SATs corresponding to one or more satellite transmission paths from the first SAT to the second SAT. Optionally, sending the link delay information to the UE includes: and sending a first broadcast message, wherein the first broadcast message comprises the link delay information.

Optionally, the first broadcast message is a system information block SIB message.

Optionally, the network device is a core network element.

Optionally, the core network element is a mobility management function AMF.

According to an embodiment of the present disclosure, the satellite 1900 may perform a method according to the second aspect of the present disclosure. As shown in fig. 19, the satellite 1900 may include a sending unit 1902, and the sending unit 1902 may be configured to send a first message to the network device, wherein the first message includes a NAS request message for a target service, and the first message includes link delay information.

Optionally, the satellite further comprises a determining unit 1903, the determining unit 1903 being configured to determine the link delay information from preconfigured information.

Optionally, the satellite 1900 further includes a receiving unit 1901, where the receiving unit 1901 is configured to receive the NAS request message, where the NAS request message is transmitted to the second SAT via a first satellite transmission path of the one or more satellite transmission paths, and the link delay information indicates a link delay corresponding to the first satellite transmission path.

Optionally, the link delay corresponding to the first satellite transmission path includes a first delay of the first satellite transmission path.

Optionally, the link delay information includes: the number of satellite hops information included in the first satellite transmission path; or ISL delay information corresponding to the first satellite transmission path.

Optionally, the link delay information is information of the number of satellite hops included in the first satellite transmission path, where ISL delay corresponding to each satellite hop is the same.

Optionally, the preconfigured information includes at least one of: the number of satellite hops corresponding to one or more satellite transmission paths from the first SAT to the second SAT; ISL time delay corresponding to one or more satellite transmission paths from the first SAT to the second SAT; one or more SATs corresponding to one or more satellite transmission paths from the first SAT to the second SAT.

Optionally, the network device is a core network element.

Optionally, the core network element is a mobility management function AMF.

According to an embodiment of the present disclosure, the satellite 1900 may perform a method according to the sixth aspect of the present disclosure. As shown in fig. 19, the satellite 1900 may include a receiving unit 1901, and the receiving unit 1901 may be configured to receive a first message for requesting a service corresponding to a target service. As shown in fig. 19, the satellite 1900 may further include a determining unit 1903, where the determining unit 1903 is configured to determine link delay information; and determining whether to forward the first message according to the link delay information.

Optionally, the determining unit 1903 is configured to determine whether the link delay indicated by the link delay information meets the delay requirement of the target service; forwarding the first message under the condition that the indicated link delay meets the delay requirement of the target service; and/or not forwarding the first message in case the indicated link delay does not meet the delay requirement of the target service.

Optionally, the indicated link delay comprises a first link delay of at least one of the one or more satellite transmission paths.

Optionally, the first message carries the link delay information.

Optionally, the first message is transmitted from the first SAT to the third SAT via a first satellite transmission path of the one or more satellite transmission paths, and the link delay information indicates a link delay from the first SAT to the third SAT.

Optionally, the link delay information includes: information on the number of hops of the satellite; or ISL latency information.

Optionally, the link delay information is information of a number of hops of a satellite, the information of the number of hops of the satellite indicating a threshold of the number of hops of the satellite and a number of hops of the satellite that the first message experiences.

Optionally, the number of satellite hops threshold indicates a number of satellite hops allowed by the delay requirement of the target service, and the number of satellite hops threshold is determined by the first SAT based on a mapping relationship between a preconfigured target service delay and a number of allowed satellite hops.

Optionally, the number of satellite hops the first message experiences indicates: the number of satellite hops the first message experiences N1 before reaching the third SAT; or the number of satellite hops N2 the first message experiences to reach the third SAT.

Optionally, the determining unit 1903 is configured to: forwarding the first message if the number of satellite hops experienced by the first message does not exceed the number of satellite hops threshold; and/or if the number of satellite hops experienced by the first message exceeds the number of satellite hops threshold, not forwarding the first message.

Optionally, the SAT further comprises an updating unit 1904, the updating unit 1904 being configured to update the number of satellite hops undergone by the first message comprised by the link delay information before forwarding the first message.

Optionally, the updating unit 1904 is configured to add 1 to the number of satellite hops the first message experiences.

Optionally, the link delay information is ISL delay information, where the ISL delay information indicates an ISL delay threshold and one or more delays corresponding to ISL experienced by the first message.

Optionally, the ISL latency threshold indicates an ISL latency allowed by a latency requirement of the target service, and the ISL latency threshold is determined by the first SAT based on a mapping relationship between a preconfigured target service latency and an allowed ISL latency.

Optionally, the first message experiences one or more latency indications corresponding to ISL: a total delay t1 of one or more ISLs experienced by the first message to reach the third SAT; or a total delay t2 of the first message arriving at the one or more ISLs experienced by the third SAT.

Optionally, the determining unit 1903 is configured to: if the time delay corresponding to one or more ISLs experienced by the first message does not exceed the ISL time delay threshold, forwarding the first message; and/or if the delay corresponding to one or more ISLs experienced by the first message exceeds the ISL delay threshold, not forwarding the first message. Optionally, before forwarding the first message, updating the delay corresponding to one or more ISLs experienced by the first message included in the link delay information.

Optionally, the determining unit 1903 is configured to: determining a satellite ID of a fourth SAT connected to the third SAT, wherein the fourth SAT is a satellite from which the third SAT receives the first message or a satellite towards which the third SAT forwards the first message; and determining the time delay corresponding to the ISL link between the fourth SAT and the third SAT according to the corresponding relation between the preconfigured ISL time delay and the satellite ID. The updating unit 1904 is configured to: and adding the delay corresponding to the ISL link between the fourth SAT and the third SAT to the delay corresponding to one or more ISLs experienced by the first message.

Optionally, the first message carries a second link delay of the UE to the first SAT.

Optionally, the link latency information indicates a total link latency from the UE to the third SAT,

the determination unit is configured to: determining a first link delay of the first SAT to the third SAT; and determining a total link delay of the UE to the third SAT according to the first link delay and the second link delay.

Optionally, determining whether to forward the first message according to the link delay information includes: if the total link delay from the UE to the third SAT does not exceed the delay requirement of the target service, forwarding the first message; and/or if the total link delay of the UE to the third SAT exceeds the delay requirement of the target service, not forwarding the first message.

Optionally, the third SAT determines a first link delay from the first SAT to the third SAT according to preconfigured information, wherein the preconfigured information comprises at least one of the following: the number of satellite hops corresponding to one or more satellite transmission paths from the first SAT to the third SAT; ISL time delay corresponding to one or more satellite transmission paths from the first SAT to the third SAT; one or more SATs corresponding to one or more satellite transmission paths from the first SAT to the third SAT.

Optionally, the first message carries time information T1, and the T1 indicates a time when the UE sends a NAS request message for the target service.

Optionally, the determining unit 1903 is configured to: determining time information T2, the T2 indicating a time at which the first message was received by the third SAT; a total link delay from the UE to the third SAT is determined, wherein the total link delay is determined from a difference between the time information T2 and the time information T1.

Optionally, the determining unit 1903 is configured to: forwarding the first message if the total link delay from the UE to the third SAT meets the delay requirement of the target service; and/or if the total link delay from the UE to the third SAT does not meet the delay requirement of the target service, not forwarding the first message.

Optionally, the first message is a NAS request message for the target service, where the NAS request message is initiated by the UE.

Optionally, the first message includes a NAS request message for the target service, the NAS request message being initiated by the UE.

Optionally, the first message includes a NAS request message for the target service, where the NAS request message is initiated by the UE, and the NAS request message carries the time information T1.

Optionally, the forwarding the first message includes: forwarding the first message to a next satellite; or forwarding the first message to the network device.

Optionally, the network device is a core network element.

Optionally, the core network element is a mobility management function AMF.

According to an embodiment of the present disclosure, the satellite 1900 may perform a method according to the seventh aspect of the present disclosure. As shown in fig. 19, the satellite 1900 may include a receiving unit 1901, and the receiving unit 1901 may be configured to receive a NAS request message for a target service from the UE. As shown in fig. 19, the satellite 1900 may include a determining unit 1903, where the determining unit 1903 is configured to determine a satellite transmission path delay threshold allowed by a delay requirement of the target service. As shown in fig. 19, the satellite 1900 may include a sending unit 1902, the sending unit 1902 being configured to send a first message, wherein the first message includes an allowed satellite transmission path delay threshold and the NAS request message.

Optionally, the allowed satellite transmission path delay threshold includes: a number of satellite hops threshold; or an ISL latency threshold.

Optionally, the allowed satellite transmission path delay threshold is a number of satellite hops threshold, wherein determining the satellite transmission path delay threshold allowed by the delay requirement of the target service includes: and determining a threshold value of the number of satellite hops corresponding to the time delay requirement of the target service based on a mapping relation between the preconfigured target service time delay and the allowed number of satellite hops.

Optionally, the allowed satellite transmission path delay threshold is an ISL delay threshold, and the determining unit is configured to: and determining an ISL delay threshold corresponding to the delay requirement of the target service based on a mapping relation between the preconfigured target service delay and the allowed ISL delay.

Optionally, the sending unit 1902 is configured to: the first message is transmitted to a next SAT via a first satellite transmission path of the one or more satellite transmission paths.

Optionally, the first message further includes a satellite transmission path delay that the first message experiences, where the satellite transmission path delay that the first message experiences includes a number of hops of a satellite that the first message experiences or an ISL link delay that the first message experiences.

Optionally, the number of satellite hops the first message undergoes is 0 or 1; the ISL link latency experienced by the first message includes or does not include an ISL latency of an ISL between the first SAT and a next SAT.

Optionally, the network device is a core network element.

Optionally, the core network element is a mobility management function AMF.

Fig. 20 is a schematic block diagram of a network device 2000 in accordance with an embodiment of the present disclosure. As shown in fig. 20, the network device 2000 includes at least a receiving unit 2001 and a transmitting unit 2002. According to an embodiment of the present disclosure, the receiving unit 2001 and the transmitting unit 2002 may be integrated together as a transceiving unit. Optionally, the network device 2000 further comprises a determining unit 2003.

According to an embodiment of the present disclosure, the network device 2000 may perform the method according to the fifth aspect of the present disclosure. As shown in fig. 20, the network device 2000 may include a receiving unit 2001, and the receiving unit 2001 may be configured to receive a first message from a second SAT of the plurality of SATs, the first message being for requesting a service corresponding to a target traffic, and the first message including link delay information. As shown in fig. 20, the network device 2000 may further include a determining unit 2003, where the determining unit 2003 is configured to determine whether to accept the NAS request for the target service according to the link delay information.

Optionally, the first message is a non-access stratum NAS request message for the target service, and the NAS request message includes the link delay information.

Optionally, the link delay corresponding to the at least one of the one or more satellite transmission paths includes:

a first delay of the at least one of the one or more satellite transmission paths from the first SAT to the second SAT.

Optionally, the link delay corresponding to the at least one of the one or more satellite transmission paths further comprises at least one of:

a second delay from the UE to the first SAT; and

and a third delay from the second SAT to the network device.

Optionally, the ISL delay corresponding to each satellite hop is the same.

Optionally, the link delay information is ISL delay information, where the ISL delay information indicates an ISL delay of a satellite transmission path corresponding to a minimum ISL delay or a maximum ISL delay of the one or more satellite transmission paths.

Optionally, the first message is transmitted to the network device through the second SAT.

Optionally, the first message includes a NAS request message for the target service and includes the link latency information.

Optionally, the link delay information indicates a link delay corresponding to a first satellite transmission path of the one or more satellite transmission paths, wherein the NAS request message is transmitted to the second SAT via the first satellite transmission path.

Optionally, the link delay information includes: a number of satellite hops included in the first satellite transmission path; or the ISL delay corresponding to the first satellite transmission path.

Optionally, the link delay information is a number of satellite hops included in the first satellite transmission path, where each satellite hop corresponds to a fixed delay T.

Optionally, the NAS request message includes a service request message for the target service or a PDU session establishment request for the target service.

Alternatively, the determination unit 2003 is configured to: determining whether the link delay indicated by the link delay information meets the delay requirement of the target service; and when the indicated link delay meets the delay requirement of the target service, accepting the NAS request aiming at the target service, or when the indicated link delay does not meet the delay requirement of the target service, not accepting the NAS request aiming at the target service.

Optionally, the not accepting the NAS request for the target service includes: a service request rejection message is sent.

Optionally, the network device is a core network element.

Optionally, the core network element is a mobility management function AMF.

Fig. 21 is a schematic block diagram of a communication device according to an embodiment of the present disclosure. The communication device 2100 illustrated in fig. 21 includes a processor 2102, and the processor 2102 may call and execute a computer program from the memory 2103 to implement the methods in embodiments of the present application. The memory 2103 may be a separate device from the processor 2102 or may be integrated into the processor 2102.

Optionally, as shown in fig. 21, the communication device 1200 may further include a transceiver 2101, and the processor 2101 may control the transceiver 2101 to communicate with other devices, and in particular, may send information or data to other devices, or receive information or data sent by other devices.

Alternatively, the transceiver 2101 may include a transmitter and a receiver. The transceiver 2101 may also further include an antenna, the number of which may be one or more.

Optionally, the communication device 2101 may be specifically a terminal device of an embodiment of the disclosure, and the communication device 2101 may implement the third aspect and the fourth aspect of the embodiment of the disclosure, and corresponding processes in each method implemented by the terminal device, which are not described herein for brevity.

Optionally, the communication device 2101 may be a satellite in an embodiment of the disclosure, and the communication device 2101 may implement the first aspect, the second aspect, the sixth aspect, the seventh aspect, and corresponding processes implemented by the satellite in the respective methods, which are not described herein for brevity.

Optionally, the communication device 2101 may be specifically a network device of an embodiment of the disclosure, and the communication device 2101 may implement the fifth aspect of the embodiment of the disclosure, and corresponding flows implemented by the network device in each method, which are not described herein for brevity.

Fig. 22 is a schematic structural diagram of a computer device 2200 of an embodiment of the present application. The computer device 2200 shown in fig. 22 includes a processor 2210, and the processor 2210 can call and run a computer program from the memory 2220 to implement the method in the embodiments of the application. Memory 2220 may be a separate device from processor 2210 or may be integrated in processor 2210.

Optionally, computer device 2200 may also include an input interface 2230. Wherein processor 2210 may control the input interface 2230 to communicate with other devices or devices, and in particular, may obtain information or data sent by other devices or devices.

Optionally, computer device 2200 may also include an output interface 2240. Wherein the processor 2210 may control the output interface 2240 to communicate with other devices or apparatuses, in particular, may output information or data to other devices or apparatuses.

Optionally, the computer device 2200 may be applied to a terminal device in the embodiment of the present application, and the computer device 2200 may implement a corresponding flow implemented by the terminal device in each method in the embodiment of the present application, which is not described herein for brevity.

Optionally, the computer device 2200 may be applied to a satellite in the embodiment of the present application, and the computer device 2200 may implement a corresponding procedure implemented by the satellite in each method in the embodiment of the present application, which is not described herein for brevity.

Optionally, the computer device 2200 may be applied to a network device in the embodiments of the present application, and the computer device 2200 may implement a corresponding flow implemented by the network device in each method in the embodiments of the present application, which is not described herein for brevity.

It should be appreciated that the computer device 2200 referred to in the embodiments of the present application may be a chip, which may also be referred to as a system-on-chip, or a system-on-chip, etc.

The embodiment of the present disclosure also provides a computer-readable storage medium for storing a program. The computer-readable storage medium is applicable to the communication device provided in the embodiments of the present disclosure, and the program causes a computer to execute the method performed by the communication device in the various embodiments of the present disclosure.

Embodiments of the present disclosure also provide a computer program product. The computer program product includes a program. The computer program product is applicable to a communication device provided in the embodiments of the present disclosure, and the program causes a computer to execute the method performed by the communication device in the various embodiments of the present disclosure.

The disclosed embodiments also provide a computer program. The computer program is applicable to a communication device provided by the embodiments of the present disclosure, and causes a computer to perform the methods performed by the communication device in the various embodiments of the present disclosure.

It should be understood that in the disclosed embodiments, "B corresponding to a" means that B is associated with a from which B may be determined. It should also be understood that determining B from a does not mean determining B from a alone, but may also determine B from a and/or other information.

It should be understood that the term "and/or" is merely an association relationship describing the associated object, and means that three relationships may exist, for example, a and/or B may mean: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

It should be understood that, in various embodiments of the present disclosure, the sequence numbers of the foregoing processes do not mean the order of execution, and the order of execution of the processes should be determined by their functions and internal logic, and should not constitute any limitation on the implementation of the embodiments of the present disclosure.

In the several embodiments provided in the present disclosure, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be through some interface, indirect coupling or communication connection of devices or units, electrical, mechanical, or other form.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present disclosure may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, produces a flow or function in accordance with embodiments of the present disclosure, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by a wired (e.g., coaxial cable, fiber optic, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be read by a computer or a data storage device such as a server, data center, etc. that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a digital versatile disk (digital video disc, DVD)), or a semiconductor medium (e.g., a Solid State Disk (SSD)), or the like.

The foregoing is merely specific embodiments of the disclosure, but the protection scope of the disclosure is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the disclosure, and it is intended to cover the scope of the disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims

A method of communication in a non-terrestrial network NTN, the NTN providing communication with a network device for a user device UE by means of a plurality of satellite SATs, the plurality of SATs comprising a first SAT, the first SAT being connected to the UE, the plurality of SATs comprising a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISLs, each ISL corresponding to one satellite hop, the method being applied to the first SAT, comprising:

and transmitting link delay information to the UE, wherein the link delay information indicates a link delay corresponding to at least one satellite transmission path in the one or more satellite transmission paths.
The method of claim 1, further comprising: and determining the link delay information according to the preconfigured information.
The method of claim 1 or 2, wherein the link delay corresponding to the at least one of the one or more satellite transmission paths comprises:

a first delay of at least one of the one or more satellite transmission paths from the first SAT to the second SAT.
The method of claim 3, wherein the link delay corresponding to the at least one of the one or more satellite transmission paths further comprises at least one of:

a second delay from the UE to the first SAT; and

and a third delay from the second SAT to the network device.
The method of any of claims 1-4, wherein the link latency information comprises: number of satellite hops information; or ISL latency information.
The method of any of claims 1-5, wherein the at least one of the one or more satellite transmission paths comprises: at least one satellite transmission path between the first SAT and the second SAT through which messages are transmitted.
The method of any of claims 1-5, wherein the at least one of the one or more satellite transmission paths comprises: a satellite transmission path corresponding to a minimum number of satellite hops or a maximum number of satellite hops among the one or more satellite transmission paths.
The method of claim 7, wherein the link delay information is satellite hop count information indicating a number of satellite hops included in a satellite transmission path of the one or more satellite transmission paths corresponding to a minimum or maximum number of satellite hops.
The method of claim 8, wherein the ISL delay for each satellite hop is the same.
The method of any of claims 1-5, wherein the at least one of the one or more satellite transmission paths comprises: and the one or more satellite transmission paths correspond to the satellite transmission path with the minimum ISL delay or the maximum ISL delay.
The method of claim 10, wherein the link latency information is ISL latency information indicating an ISL latency corresponding to a satellite transmission path of the one or more satellite transmission paths that corresponds to a minimum ISL latency or a maximum ISL latency.
The method of claim 2, wherein the preconfigured information comprises at least one of:

the number of satellite hops corresponding to one or more satellite transmission paths from the first SAT to the second SAT;

ISL time delay corresponding to one or more satellite transmission paths from the first SAT to the second SAT;

one or more SATs corresponding to one or more satellite transmission paths from the first SAT to the second SAT.
The method of any of claims 1-12, wherein transmitting the link latency information to the UE comprises: and sending a first broadcast message, wherein the first broadcast message comprises the link delay information.
The method of claim 13, wherein the first broadcast message is a system information block, SIB, message.
The method according to any of claims 1-14, wherein the network device is a core network element.
The method of claim 15, wherein the core network element is an access management function, AMF.
A satellite SAT located in a non-terrestrial network NTN, for performing a communication method in the NTN, the satellite SAT being a first SAT of a plurality of SATs included in the NTN, the NTN providing communication with a network device for a user equipment UE through the plurality of SATs, the first SAT being connected to the UE, a second SAT of the plurality of SATs being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISLs, each ISL corresponding to one satellite hop, the method comprising:

And a transmitting unit configured to transmit link delay information to the UE, wherein the link delay information indicates a link delay corresponding to at least one of the one or more satellite transmission paths.
The SAT of claim 1, further comprising a determination unit configured to determine the link delay information from preconfigured information.
The SAT of claim 17 or 18, wherein a link delay corresponding to the at least one of the one or more satellite transmission paths comprises:

a first delay of at least one of the one or more satellite transmission paths from the first SAT to the second SAT.
The SAT of claim 19, wherein a link delay corresponding to the at least one of the one or more satellite transmission paths further comprises at least one of:

a second delay from the UE to the first SAT; and

and a third delay from the second SAT to the network device.
The SAT of any of claims 17-20, wherein the link latency information comprises: number of satellite hops information; or ISL latency information.
The SAT of any of claims 17-21, wherein the at least one of the one or more satellite transmission paths comprises: at least one satellite transmission path between the first SAT and the second SAT through which messages are transmitted.
The SAT of any of claims 17-21, wherein the at least one of the one or more satellite transmission paths comprises: a satellite transmission path corresponding to a minimum number of satellite hops or a maximum number of satellite hops among the one or more satellite transmission paths.
The SAT of claim 23, wherein the link delay information is satellite hop count information indicating a number of satellite hops included in a satellite transmission path of the one or more satellite transmission paths corresponding to a minimum number of satellite hops or a maximum number of satellite hops.
The SAT of claim 24, wherein an ISL delay corresponding to each satellite hop is the same.
The SAT of any of claims 17-21, wherein the at least one of the one or more satellite transmission paths comprises: and the one or more satellite transmission paths correspond to the satellite transmission path with the minimum ISL delay or the maximum ISL delay.
The SAT of claim 26, wherein the link latency information is ISL latency information indicating an ISL latency corresponding to a satellite transmission path of the one or more satellite transmission paths that corresponds to a minimum ISL latency or a maximum ISL latency.
The SAT of claim 18, wherein the preconfigured information comprises at least one of:

the number of satellite hops corresponding to one or more satellite transmission paths from the first SAT to the second SAT;

ISL time delay corresponding to one or more satellite transmission paths from the first SAT to the second SAT;

one or more SATs corresponding to one or more satellite transmission paths from the first SAT to the second SAT.
The SAT of any of claims 17-28, wherein to send the link latency information to the UE comprises to: and sending a first broadcast message, wherein the first broadcast message comprises the link delay information.
The SAT of claim 29, wherein the first broadcast message is a system information block, SIB, message.
The SAT of any of claims 17-30, wherein the network device is a core network element.
The SAT of claim 31, wherein the core network element is an access management function, AMF.
A method of communication in a non-terrestrial network NTN, the NTN providing communication with a network device for a user equipment UE through a plurality of SATs, the plurality of SATs including a first SAT, the first SAT being connected to the UE, the plurality of SATs including a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISLs, each ISL corresponding to one satellite hop, the method being applied to the second SAT, comprising:

a first message is sent to the network device, wherein the first message comprises a NAS request message for a target service and the first message includes link delay information.
The method of claim 33, further comprising: and determining the link delay information according to the preconfigured information.
The method of claim 33 or 34, further comprising: and receiving the NAS request message, wherein the NAS request message is transmitted to the second SAT through a first satellite transmission path in the one or more satellite transmission paths, and the link delay information indicates the link delay corresponding to the first satellite transmission path.
The method of claim 35, wherein the link delay corresponding to the first satellite transmission path comprises a first delay of the first satellite transmission path.
The method of claim 36, wherein the link delay corresponding to the first satellite transmission path further comprises at least one of:

a second delay from the UE to the first SAT; and

and a third delay from the second SAT to the network device.
The method of any of claims 33-37, wherein the link latency information comprises: the number of satellite hops information included in the first satellite transmission path; or ISL delay information corresponding to the first satellite transmission path.
The method of claim 38, wherein the link delay information is information of a number of satellite hops included in the first satellite transmission path, wherein an ISL delay corresponding to each satellite hop is the same.
The method of claim 34, wherein the preconfigured information comprises at least one of:

the number of satellite hops corresponding to one or more satellite transmission paths from the first SAT to the second SAT;

ISL time delay corresponding to one or more satellite transmission paths from the first SAT to the second SAT;

one or more SATs corresponding to one or more satellite transmission paths from the first SAT to the second SAT.
The method of any one of claims 33-40, wherein the network device is a core network element.
The method of claim 41, wherein the core network element is an access management function, AMF.
A satellite SAT located in a non-terrestrial network NTN, for performing a communication method in the NTN, the satellite SAT being a second SAT of a plurality of SATs included in the NTN, the NTN providing communication with a network device for a user equipment UE through the plurality of SATs, a first SAT of the plurality of SATs being connected to the UE, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISLs, each ISL corresponding to one satellite hop, the method comprising:

a sending unit configured to send a first message to the network device, wherein the first message comprises a NAS request message for a target service, and the first message comprises link delay information.
The SAT of claim 43, further comprising: and the determining unit is configured to determine the link delay information according to the preconfigured information.
The SAT of claim 43 or 44, further comprising: and a receiving unit configured to receive the NAS request message, where the NAS request message is transmitted to the second SAT via a first satellite transmission path of the one or more satellite transmission paths, and the link delay information indicates a link delay corresponding to the first satellite transmission path.
The SAT of claim 45, wherein the link delay corresponding to the first satellite transmission path comprises a first delay of the first satellite transmission path.
The SAT of claim 46, wherein a link delay corresponding to the first satellite transmission path further comprises at least one of:

a second delay from the UE to the first SAT; and

and a third delay from the second SAT to the network device.
The SAT of any of claims 43-47, wherein the link latency information comprises: the number of satellite hops information included in the first satellite transmission path; or ISL delay information corresponding to the first satellite transmission path.
The SAT of claim 48 wherein said link delay information is information of a number of satellite hops included in said first satellite transmission path, wherein each satellite hop corresponds to the same ISL delay.
The SAT of claim 44, wherein the preconfigured information comprises at least one of:

the number of satellite hops corresponding to one or more satellite transmission paths from the first SAT to the second SAT;

ISL time delay corresponding to one or more satellite transmission paths from the first SAT to the second SAT;

one or more SATs corresponding to one or more satellite transmission paths from the first SAT to the second SAT.
The SAT of any of claims 43-50, wherein the network device is a core network element.
The SAT of claim 51 wherein the core network element is an Access management function AMF.
A method of communication in a non-terrestrial network NTN, the NTN providing communication with a network device for a user equipment UE by means of a plurality of SATs, the plurality of SATs comprising a first SAT, the first SAT being connected to the UE, the plurality of SATs comprising a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISLs, each ISL corresponding to a satellite hop, the method comprising, applied to the UE:

Receiving link delay information sent by a first SAT in the plurality of SATs, wherein the link delay information indicates link delay corresponding to at least one satellite transmission path in the one or more satellite transmission paths;

and determining whether to initiate a non-access stratum (NAS) request message aiming at the target service according to the link delay information.
The method of claim 53, wherein the link delay corresponding to the at least one of the one or more satellite transmission paths comprises:

a first delay of at least one of the one or more satellite transmission paths from the first SAT to the second SAT.
The method of claim 54, wherein the link delay corresponding to the at least one of the one or more satellite transmission paths further comprises at least one of:

a second delay from the UE to the first SAT; and

and a third delay from the second SAT to the network device.
The method of any of claims 53-55, wherein the link latency information comprises: number of satellite hops information; or ISL latency information.
The method of any of claims 53-56, wherein the at least one of the one or more satellite transmission paths comprises: at least one satellite transmission path between the first SAT and the second SAT through which messages are transmitted.
The method of any of claims 53-56, wherein the at least one of the one or more satellite transmission paths comprises: a satellite transmission path corresponding to a minimum number of satellite hops or a maximum number of satellite hops among the one or more satellite transmission paths.
The method of claim 58, wherein the link delay information is satellite hop count information indicating a number of satellite hops included in a satellite transmission path corresponding to a minimum or maximum number of satellite hops in the one or more satellite transmission paths.
The method of claim 59, wherein each satellite hop corresponds to the same ISL latency.
The method of any of claims 53-56, wherein the at least one of the one or more satellite transmission paths comprises: and the one or more satellite transmission paths correspond to the satellite transmission path with the minimum ISL delay or the maximum ISL delay.
The method of claim 61, wherein the link latency information is ISL latency information indicating an ISL latency corresponding to a satellite transmission path of the one or more satellite transmission paths that corresponds to a minimum ISL latency or a maximum ISL latency.
The method of claim 53, wherein receiving link latency information transmitted by a first SAT of the plurality of SATs comprises: and receiving a first broadcast message sent by the first SAT, wherein the first broadcast message comprises the link delay information.
The method of claim 63, wherein the broadcast message is a system information block SIB message.
The method of claim 53, wherein determining whether to initiate a NAS request message for a target service based on the link latency information comprises:

determining whether the link delay indicated by the link delay information meets the delay requirement of the target service;

under the condition that the link delay indicated by the link delay information meets the delay requirement of the target service, initiating a NAS request message aiming at the target service; and/or under the condition that the link delay indicated by the link delay information does not meet the delay requirement of the target service, not initiating the NAS request message aiming at the target service.
The method of claim 65, wherein the NAS request message comprises a service request for the target traffic or a PDU session establishment request for the target traffic.
The method of any of claims 53-66, wherein the network device is a core network element.
The method of claim 67, wherein the core network element is an access management function, AMF.
A user equipment, UE, connected to a network device through a non-terrestrial network, NTN, wherein the NTN provides communication with the network device for the UE through a plurality of SATs, the plurality of SATs including a first SAT, the first SAT being connected to the UE, the plurality of SATs including a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links, ISLs, each ISL corresponding to a satellite hop, comprising:

a receiving unit configured to receive link delay information transmitted by a first SAT of the plurality of SATs, wherein the link delay information indicates a link delay corresponding to at least one satellite transmission path of the one or more satellite transmission paths;

And the determining unit is configured to determine whether to initiate a non-access stratum NAS request message aiming at the target service according to the link delay information.
The UE of claim 69, wherein the link delay corresponding to the at least one of the one or more satellite transmission paths comprises:

a first delay of at least one of the one or more satellite transmission paths from the first SAT to the second SAT.
The UE of claim 70, wherein the link delay corresponding to the at least one of the one or more satellite transmission paths further comprises at least one of:

a second delay from the UE to the first SAT; and

and a third delay from the second SAT to the network device.
The UE of any of claims 69-71, wherein the link delay information comprises: number of satellite hops information; or ISL latency information.
The UE of any of claims 69-72, wherein the at least one of the one or more satellite transmission paths comprises: at least one satellite transmission path between the first SAT and the second SAT through which messages are transmitted.
The UE of any of claims 69-72, wherein the at least one of the one or more satellite transmission paths comprises: a satellite transmission path corresponding to a minimum number of satellite hops or a maximum number of satellite hops among the one or more satellite transmission paths.
The UE of claim 74, wherein the link delay information is satellite hop count information indicating a number of satellite hops included in a satellite transmission path of the one or more satellite transmission paths corresponding to a minimum or maximum number of satellite hops.
The UE of claim 75, wherein the ISL latency for each satellite hop is the same.
The UE of any of claims 69-72, wherein the at least one of the one or more satellite transmission paths comprises: and the one or more satellite transmission paths correspond to the satellite transmission path with the minimum ISL delay or the maximum ISL delay.
The UE of claim 77, wherein the link delay information is ISL delay information indicating an ISL delay corresponding to a satellite transmission path of the one or more satellite transmission paths that corresponds to a minimum ISL delay or a maximum ISL delay.
The UE of claim 69, the receiving unit configured to receive a first broadcast message sent by the first SAT, wherein the first broadcast message includes the link delay information therein.
The UE of claim 79, wherein the broadcast message is a system information block, SIB, message.
The UE of claim 69, the determining unit configured to:

determining whether the link delay indicated by the link delay information meets the delay requirement of the target service;

under the condition that the link delay indicated by the link delay information meets the delay requirement of the target service, initiating a NAS request message aiming at the target service; and/or under the condition that the link delay indicated by the link delay information does not meet the delay requirement of the target service, not initiating the NAS request message aiming at the target service.
The UE of claim 81, wherein the NAS request message comprises a service request for the target traffic or a PDU session establishment request for the target traffic.
The UE of any of claims 69-82, wherein the network device is a core network element.
The UE of claim 83, wherein the core network element is an access management function, AMF.
A method of communication in a non-terrestrial network NTN, the NTN providing communication with a network device for a user equipment UE by means of a plurality of SATs, the plurality of SATs comprising a first SAT, the first SAT being connected to the UE, the plurality of SATs comprising a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISLs, each ISL corresponding to a satellite hop, the method comprising, applied to the UE:

receiving link delay information sent by a first SAT in the plurality of SATs, wherein the link delay information indicates link delay corresponding to at least one satellite transmission path in the one or more satellite transmission paths;

and sending a non-access stratum (NAS) request message aiming at the target service, wherein the NAS request message comprises the link delay information.
The method of claim 85, wherein the link delay corresponding to the at least one of the one or more satellite transmission paths comprises:

A first delay of at least one of the one or more satellite transmission paths from the first SAT to the second SAT.
The method of claim 86, wherein the link delay corresponding to the at least one of the one or more satellite transmission paths further comprises at least one of:

a second delay from the UE to the first SAT; and

and a third delay from the second SAT to the network device.
The method of any of claims 85-87, wherein the link latency information comprises: number of satellite hops information; or ISL latency information.
The method of any of claims 85-88, wherein the at least one of the one or more satellite transmission paths comprises: at least one satellite transmission path between the first SAT and the second SAT through which messages are transmitted.
The method of any of claims 85-88, wherein the at least one of the one or more satellite transmission paths comprises: a satellite transmission path corresponding to a minimum number of satellite hops or a maximum number of satellite hops among the one or more satellite transmission paths.
The method of claim 90, wherein the link delay information is satellite hop count information indicating a number of satellite hops included in a satellite transmission path of the one or more satellite transmission paths corresponding to a minimum or maximum number of satellite hops.
The method of claim 91, wherein each satellite hop corresponds to the same ISL latency.
The method of any of claims 85-88, wherein the at least one of the one or more satellite transmission paths comprises: and the one or more satellite transmission paths correspond to the satellite transmission path with the minimum ISL delay or the maximum ISL delay.
The method of claim 93, wherein the link latency information is ISL latency information indicating an ISL latency corresponding to a satellite transmission path of the one or more satellite transmission paths that corresponds to a minimum ISL latency or a maximum ISL latency.
The method of claim 85, wherein receiving link latency information transmitted by a first SAT of the plurality of SATs comprises: and receiving a first broadcast message sent by the first SAT, wherein the first broadcast message comprises the link delay information.
The method of claim 95, wherein the broadcast message is a system information block, SIB, message.
The method of claim 85, wherein the NAS request message comprises a service request for the target traffic or a PDU session establishment request for the target traffic.
The method of any one of claims 85-97, wherein the network device is a core network element.
The method of claim 98, wherein the core network element is an access management function, AMF.
A user equipment, UE, connected to a network device through a non-terrestrial network, NTN, wherein the NTN provides communication with the network device for the UE through a plurality of SATs, the plurality of SATs including a first SAT, the first SAT being connected to the UE, the plurality of SATs including a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links, ISLs, each ISL corresponding to a satellite hop, comprising:

a receiving unit configured to receive link delay information transmitted by a first SAT of the plurality of SATs, wherein the link delay information indicates a link delay corresponding to at least one satellite transmission path of the one or more satellite transmission paths;

And the sending unit is configured to send a non-access stratum (NAS) request message aiming at the target service, wherein the NAS request message comprises the link delay information.
The UE of claim 100, wherein a link delay corresponding to the at least one of the one or more satellite transmission paths comprises:

a first delay of at least one of the one or more satellite transmission paths from the first SAT to the second SAT.
The UE of claim 101, wherein the link delay corresponding to the at least one of the one or more satellite transmission paths further comprises at least one of:

a second delay from the UE to the first SAT; and

and a third delay from the second SAT to the network device.
The UE of any of claims 100-102, wherein the link delay information comprises: number of satellite hops information; or ISL latency information.
The UE of any of claims 100-103, wherein the at least one of the one or more satellite transmission paths comprises: at least one satellite transmission path between the first SAT and the second SAT through which messages are transmitted.
The UE of any of claims 100-103, wherein the at least one of the one or more satellite transmission paths comprises: a satellite transmission path corresponding to a minimum number of satellite hops or a maximum number of satellite hops among the one or more satellite transmission paths.
The UE of claim 105, wherein the link delay information is satellite hop count information indicating a number of satellite hops included in a satellite transmission path of the one or more satellite transmission paths corresponding to a minimum or maximum number of satellite hops.
The UE of claim 106, wherein the ISL latency for each satellite hop is the same.
The UE of any of claims 100-103, wherein the at least one of the one or more satellite transmission paths comprises: and the one or more satellite transmission paths correspond to the satellite transmission path with the minimum ISL delay or the maximum ISL delay.
The UE of claim 108, wherein the link delay information is ISL delay information indicating an ISL delay corresponding to a satellite transmission path of the one or more satellite transmission paths that corresponds to a minimum ISL delay or a maximum ISL delay.
The UE of claim 100, the receiving unit configured to receive a first broadcast message sent by the first SAT, wherein the first broadcast message includes the link delay information therein.
The UE of claim 110, wherein the broadcast message is a system information block, SIB, message.
The UE of claim 100, wherein the NAS request message includes a service request for the target traffic or a PDU session establishment request for the target traffic.
The UE of any of claims 100-112, wherein the network device is a core network element.
The UE of claim 113, wherein the core network element is an access management function, AMF.
A method of communication in a non-terrestrial network NTN, the NTN providing communication with a network device for a user equipment UE by means of a plurality of SATs, the plurality of SATs comprising a first SAT, the first SAT being connected to the UE, the plurality of SATs comprising a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISLs, each ISL corresponding to a satellite hop, the method being applied to the network device, comprising:

Receiving a first message from a second SAT in the plurality of SATs, wherein the first message is used for requesting a service corresponding to a target business, and the first message comprises link delay information;

and determining whether to accept the NAS request aiming at the target service according to the link delay information.
The method of claim 115, wherein the first message is a non-access stratum, NAS, request message for the target service, the NAS request message including the link latency information.
The method of claim 116, wherein the link delay information indicates a link delay corresponding to at least one of the one or more satellite transmission paths.
The method of claim 116 or 117, wherein the link delay corresponding to the at least one of the one or more satellite transmission paths comprises:

a first delay of the at least one of the one or more satellite transmission paths from the first SAT to the second SAT.
The method of claim 118, wherein the link delay corresponding to the at least one of the one or more satellite transmission paths further comprises at least one of:

A second delay from the UE to the first SAT; and

and a third delay from the second SAT to the network device.
The method of any of claims 116-119, wherein the link latency information comprises: number of satellite hops information; or ISL latency information.
The method of any of claims 117-120, wherein the at least one of the one or more satellite transmission paths comprises: at least one satellite transmission path between the first SAT and the second SAT through which messages are transmitted.
The method of any of claims 117-120, wherein the at least one of the one or more satellite transmission paths comprises: a satellite transmission path corresponding to a minimum number of satellite hops or a maximum number of satellite hops among the one or more satellite transmission paths.
The method of claim 122, wherein the link delay information is satellite hop count information indicating a number of satellite hops included in a satellite transmission path of the one or more satellite transmission paths corresponding to a minimum or maximum number of satellite hops.
The method of claim 123, wherein each satellite hop corresponds to the same ISL latency.
The method of any of claims 117-120, wherein the at least one of the one or more satellite transmission paths comprises: and the one or more satellite transmission paths correspond to the satellite transmission path with the minimum ISL delay or the maximum ISL delay.
The method of claim 125, wherein the link latency information is ISL latency information indicating an ISL latency of a satellite transmission path of the one or more satellite transmission paths that corresponds to a minimum ISL latency or a maximum ISL latency.
The method of any one of claims 116-126, wherein the first message is transparently passed to the network device via the second SAT.
The method of claim 115, wherein the first message comprises a NAS request message for the target traffic and includes the link latency information.
The method of claim 128, wherein the link delay information indicates a link delay corresponding to a first satellite transmission path of the one or more satellite transmission paths via which the NAS request message was transmitted to the second SAT.
The method of claim 129, wherein the link delay corresponding to the first satellite transmission path comprises a first delay of the first satellite transmission path.
The method of claim 130, wherein the link delay corresponding to the first satellite transmission path further comprises at least one of:

a second delay from the UE to the first SAT; and

and a third delay from the second SAT to the network device.
The method of any of claims 128-131, wherein the link latency information comprises: a number of satellite hops included in the first satellite transmission path; or the ISL delay corresponding to the first satellite transmission path.
The method of claim 132, wherein the link delay information is a number of satellite hops included in the first satellite transmission path, wherein each satellite hop corresponds to a fixed delay T.
The method of any of claims 116-133, wherein the NAS request message comprises a service request message for the target traffic or a PDU session establishment request for the target traffic.
The method of claim 115, wherein determining whether to accept the NAS request for the target traffic based on the link latency information comprises:

Determining whether the link delay indicated by the link delay information meets the delay requirement of the target service;

and when the indicated link delay meets the delay requirement of the target service, accepting the NAS request aiming at the target service, or when the indicated link delay does not meet the delay requirement of the target service, not accepting the NAS request aiming at the target service.
The method of claim 135, the not accepting a NAS request for the target traffic comprising: a service request rejection message is sent.
The method of any one of claims 115-136, wherein the network device is a core network element.
The method of claim 137, wherein the core network element is an access management function, AMF.
A network device connected to a user equipment UE through a non-terrestrial network NTN, the NTN providing communication with the network device UE through a plurality of SATs, the plurality of SATs including a first SAT, the first SAT being connected to the UE, the plurality of SATs including a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISL, each ISL corresponding to one satellite hop, comprising:

A receiving unit configured to receive a first message from a second SAT of the plurality of SATs, the first message being for requesting a service corresponding to a target traffic, and the first message including link delay information;

and the determining unit is configured to determine whether to accept the NAS request for the target service according to the link delay information.
The network device of claim 139, wherein the first message is a non-access stratum (NAS) request message for the target service, the NAS request message including the link latency information.
The network device of claim 140, wherein the link delay information indicates a link delay corresponding to at least one of the one or more satellite transmission paths.
The network device of claim 140 or 141, wherein the link delay corresponding to the at least one of the one or more satellite transmission paths comprises:

a first delay of the at least one of the one or more satellite transmission paths from the first SAT to the second SAT.
The network device of claim 142, wherein the link delay corresponding to the at least one of the one or more satellite transmission paths further comprises at least one of:

A second delay from the UE to the first SAT; and

and a third delay from the second SAT to the network device.
The network device of any of claims 140-143, wherein the link latency information includes: number of satellite hops information; or ISL latency information.
The network device of any of claims 141-144, wherein the at least one of the one or more satellite transmission paths comprises: at least one satellite transmission path between the first SAT and the second SAT through which messages are transmitted.
The network device of any of claims 141-144, wherein the at least one of the one or more satellite transmission paths comprises: a satellite transmission path corresponding to a minimum number of satellite hops or a maximum number of satellite hops among the one or more satellite transmission paths.
The network device of claim 146, wherein the link delay information is satellite hop count information indicating a number of satellite hops included in a satellite transmission path of the one or more satellite transmission paths corresponding to a minimum or maximum number of satellite hops.
The network device of claim 147, wherein the ISL latency for each satellite hop is the same.
The network device of any of claims 141-144, wherein the at least one of the one or more satellite transmission paths comprises: and the one or more satellite transmission paths correspond to the satellite transmission path with the minimum ISL delay or the maximum ISL delay.
The network device of claim 149, wherein the link latency information is ISL latency information indicating an ISL latency of a satellite transmission path of the one or more satellite transmission paths that corresponds to a minimum ISL latency or a maximum ISL latency.
The network device of any of claims 140-150, wherein the first message is transmitted transparently to the network device via the second SAT.
The network device of claim 139, wherein the first message comprises a NAS request message for the target traffic and includes the link latency information.
The network device of claim 152, wherein the link latency information indicates a link latency corresponding to a first satellite transmission path of the one or more satellite transmission paths via which the NAS request message was transmitted to the second SAT.
The network device of claim 153, wherein the link delay corresponding to the first satellite transmission path comprises a first delay of the first satellite transmission path.
The network device of claim 154, wherein the link delay corresponding to the first satellite transmission path further comprises at least one of:

a second delay from the UE to the first SAT; and

and a third delay from the second SAT to the network device.
The network device of any of claims 152-155, wherein the link latency information includes: a number of satellite hops included in the first satellite transmission path; or the ISL delay corresponding to the first satellite transmission path.
The network device of claim 156, wherein the link delay information is a number of satellite hops included in the first satellite transmission path, wherein each satellite hop corresponds to a fixed delay T.
The network device of any of claims 140-157, wherein the NAS request message comprises a service request message for the target traffic or a PDU session establishment request for the target traffic.
The network device of claim 139, the determination unit configured to:

determining whether the link delay indicated by the link delay information meets the delay requirement of the target service;

and when the indicated link delay meets the delay requirement of the target service, accepting the NAS request aiming at the target service, or when the indicated link delay does not meet the delay requirement of the target service, not accepting the NAS request aiming at the target service.
The network device of claim 159, wherein the not accepting a NAS request for the target traffic comprises: a service request rejection message is sent.
The network device of any of claims 139-160, wherein the network device is a core network element.
The network device of claim 161, wherein the core network element is an access management function, AMF.
A method of communication in a non-terrestrial network NTN, the NTN providing communication with a network device for a user device UE via a plurality of satellite SATs, the plurality of SATs comprising a first SAT, the first SAT being connected to the UE, the plurality of SATs comprising a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISLs, each ISL corresponding to one satellite hop, the method comprising:

Receiving a first message, wherein the first message is used for requesting a service corresponding to a target business;

determining link delay information; and

and determining whether to forward the first message according to the link delay information.
The method according to claim 163, wherein,

wherein determining whether to forward the first message according to the link delay information comprises:

determining whether the link delay indicated by the link delay information meets the delay requirement of the target service;

forwarding the first message under the condition that the indicated link delay meets the delay requirement of the target service; and/or not forwarding the first message in case the indicated link delay does not meet the delay requirement of the target service.
The method of claim 164, wherein the indicated link delay comprises a first link delay of at least one of the one or more satellite transmission paths.
The method of claim 165, wherein the indicated link delay further comprises at least one of: a second link delay of the UE to the first SAT; and a third link delay of the second SAT to the network device.
The method of any one of claims 163-164, wherein the first message carries the link latency information.
The method of claim 167, wherein the first message is transmitted from the first SAT to the third SAT via a first satellite transmission path of the one or more satellite transmission paths, the link delay information indicating a link delay from the first SAT to the third SAT.
The method of any of claims 167-168, wherein the link latency information comprises: information on the number of hops of the satellite; or ISL latency information.
The method of claim 169, wherein the link delay information is number of hops of a satellite information indicating a number of satellite hops threshold and a number of satellite hops the first message experiences.
The method of claim 170, wherein the number of satellite hops threshold indicates a number of satellite hops allowed by the latency requirement of the target service, the number of satellite hops threshold determined by the first SAT based on a mapping of preconfigured target service latency to a number of allowed satellite hops.
The method of claim 170, wherein the number of satellite hops the first message experiences indicates: the number of satellite hops the first message experiences N1 before reaching the third SAT; or the number of satellite hops N2 the first message experiences to reach the third SAT.
The method according to claim 170,

wherein determining whether to forward the first message according to the link delay information comprises:

forwarding the first message if the number of satellite hops experienced by the first message does not exceed the number of satellite hops threshold; and/or if the number of satellite hops experienced by the first message exceeds the number of satellite hops threshold, not forwarding the first message.
The method of claim 170, wherein the method further comprises: the number of satellite hops experienced by the first message, as comprised by the link delay information, is updated before forwarding the first message.
The method of claim 174, wherein updating the link delay information includes a number of satellite hops experienced by the first message including: adding 1 to the number of satellite hops the first message experiences.
The method of claim 171, wherein the link latency information is ISL latency information indicating an ISL latency threshold and one or more corresponding latencies experienced by the first message.
The method of claim 176, wherein the ISL latency threshold indicates an ISL latency allowed by latency requirements of the target traffic, the ISL latency threshold being determined by the first SAT based on a mapping of preconfigured target traffic latency to allowed ISL latency.
The method of claim 176, wherein the first message experiences one or more corresponding indications of latency of ISL: a total delay t1 of one or more ISLs experienced by the first message to reach the third SAT; or a total delay t2 of the first message arriving at the one or more ISLs experienced by the third SAT.
The method according to claim 176,

wherein determining whether to forward the first message according to the link delay information comprises:

if the time delay corresponding to one or more ISLs experienced by the first message does not exceed the ISL time delay threshold, forwarding the first message; and/or

And if the delay corresponding to one or more ISLs experienced by the first message exceeds the ISL delay threshold, not forwarding the first message.
The method of claim 176, wherein the method further comprises: and before forwarding the first message, updating the delay corresponding to one or more ISLs, which are experienced by the first message and included in the link delay information.
The method of claim 180, further comprising:

determining a satellite ID of a fourth SAT connected to the third SAT, wherein the fourth SAT is a satellite from which the third SAT receives the first message or a satellite towards which the third SAT forwards the first message;

determining the time delay corresponding to an ISL link between the fourth SAT and the third SAT according to the corresponding relation between the preconfigured ISL time delay and the satellite ID;

wherein the updating the delay corresponding to the one or more ISLs experienced by the first message included in the link delay information includes: and adding the delay corresponding to the ISL link between the fourth SAT and the third SAT to the delay corresponding to one or more ISLs experienced by the first message.
The method of any of claims 163-165, wherein the first message carries a second link latency of the UE to the first SAT.
The method of claim 182, wherein the link latency information indicates a total link latency from the UE to the third SAT,

Wherein said determining said link delay information comprises:

determining a first link delay of the first SAT to the third SAT; and

and determining the total link delay from the UE to the third SAT according to the first link delay and the second link delay.
The method of claim 183, wherein determining whether to forward the first message based on the link latency information comprises:

if the total link delay from the UE to the third SAT does not exceed the delay requirement of the target service, forwarding the first message; and/or

And if the total link delay from the UE to the third SAT exceeds the delay requirement of the target service, not forwarding the first message.
The method of claim 183, wherein the third SAT determines a first link delay of the first SAT to the third SAT from preconfigured information comprising at least one of:

the number of satellite hops corresponding to one or more satellite transmission paths from the first SAT to the third SAT;

ISL time delay corresponding to one or more satellite transmission paths from the first SAT to the third SAT;

one or more SATs corresponding to one or more satellite transmission paths from the first SAT to the third SAT.
The method of any of claims 163-165, wherein the first message carries time information T1, the T1 indicating a time of day at which the UE sent a NAS request message for the target service.
The method of claim 186, wherein determining the link latency information comprises:

determining time information T2, the T2 indicating a time at which the first message was received by the third SAT;

a total link delay from the UE to the third SAT is determined, wherein the total link delay is determined from a difference between the time information T2 and the time information T1.
The method of claim 187, wherein determining whether to forward the first message according to the link latency information comprises:

forwarding the first message if the total link delay from the UE to the third SAT meets the delay requirement of the target service; and/or

And if the total link delay from the UE to the third SAT does not meet the delay requirement of the target service, not forwarding the first message.
The method of any of claims 163-166, wherein the first message is a NAS request message for the target traffic, the NAS request message originated by the UE.
The method of any of claims 163-185, wherein the first message comprises a NAS request message for the target traffic, the NAS request message initiated by the UE.
The method of at least one of claims 186-188, wherein the first message comprises a NAS request message for the target service, the NAS request message being initiated by the UE, the NAS request message carrying the time information T1.
The method of at least one of claims 189 to 191, wherein the NAS request message comprises a service request for the target traffic or a PDU session establishment request for the target traffic.
The method of any of claims 163-188, wherein the forwarding the first message includes:

forwarding the first message to a next satellite; or (b)

Forwarding the first message to the network device.
The method of any one of claims 163-188, wherein the network device is a core network element.
The method of claim 194, wherein the core network element is an access management function, AMF.
A satellite SAT located in a non-terrestrial network NTN for performing a communication method in the NTN, the satellite SAT being a third SAT of a plurality of SATs included in the NTN, the NTN providing communication with a network device for a user equipment UE through the plurality of satellite SATs, the plurality of SATs including a first SAT, the first SAT being connected to the UE, the plurality of SATs including a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein the third SAT is located in the one or more satellite transmission paths, adjacent satellites in each satellite transmission path being connected by inter-satellite links ISL, each ISL corresponding to one satellite hop, the method comprising:

A receiving unit configured to receive a first message, where the first message is used to request a service corresponding to a target service;

a determination unit configured to: determining link delay information; and determining whether to forward the first message according to the link delay information.
The SAT of claim 196, the determining unit configured to:

determining whether the link delay indicated by the link delay information meets the delay requirement of the target service;

forwarding the first message under the condition that the indicated link delay meets the delay requirement of the target service; and/or not forwarding the first message in case the indicated link delay does not meet the delay requirement of the target service.
The SAT of claim 197, wherein the indicated link delay comprises a first link delay of at least one of the one or more satellite transmission paths.
The SAT of claim 198, wherein the indicated link latency further comprises at least one of: a second link delay of the UE to the first SAT; and a third link delay of the second SAT to the network device.
The SAT of any of claims 196-197, wherein the first message carries the link latency information.
The SAT of claim 200, wherein the first message is transmitted from the first SAT to the third SAT via a first satellite transmission path of the one or more satellite transmission paths, the link delay information indicating a link delay from the first SAT to the third SAT.
The SAT of any of claims 200-201, wherein the link latency information comprises: information on the number of hops of the satellite; or ISL latency information.
The SAT of claim 202, wherein the link delay information is information of a number of hops of a satellite indicative of a threshold number of satellite hops and a number of satellite hops experienced by the first message.
The SAT of claim 203, wherein the threshold number of satellite hops is indicative of a number of satellite hops allowed by a latency requirement of the target traffic, the threshold number of satellite hops being determined by the first SAT based on a mapping of preconfigured target traffic latency to a number of allowed satellite hops.
The SAT of claim 203, wherein the number of satellite hops experienced by the first message is indicative of: the number of satellite hops the first message experiences N1 before reaching the third SAT; or the number of satellite hops N2 the first message experiences to reach the third SAT.
The SAT of claim 203, the determining unit configured to:

forwarding the first message if the number of satellite hops experienced by the first message does not exceed the number of satellite hops threshold; and/or

If the number of satellite hops experienced by the first message exceeds the number of satellite hops threshold, the first message is not forwarded.
The SAT of claim 203, further comprising an updating unit configured to update a number of satellite hops experienced by the first message comprised by the link delay information prior to forwarding the first message.
The SAT of claim 207, the updating unit configured to increment by 1 a number of the satellite hops experienced by the first message.
The SAT of claim 204, wherein the link latency information is ISL latency information indicating an ISL latency threshold and one or more corresponding latencies experienced by the first message.
The SAT of claim 209, wherein the ISL latency threshold is indicative of an ISL latency allowed by latency requirements of the target traffic, the ISL latency threshold being determined by the first SAT based on a mapping of preconfigured target traffic latency to allowed ISL latency.
The SAT of claim 209, wherein the first message experiences one or more corresponding indications of latency of ISL: a total delay t1 of one or more ISLs experienced by the first message to reach the third SAT; or a total delay t2 of the first message arriving at the one or more ISLs experienced by the third SAT.
The SAT of claim 209, the determining unit configured to:

if the time delay corresponding to one or more ISLs experienced by the first message does not exceed the ISL time delay threshold, forwarding the first message; and/or

And if the delay corresponding to one or more ISLs experienced by the first message exceeds the ISL delay threshold, not forwarding the first message.
The SAT of claim 209, wherein the SAT further comprises: and before forwarding the first message, updating the delay corresponding to one or more ISLs, which are experienced by the first message and included in the link delay information.
The SAT of claim 213, the determining unit configured to:

determining a satellite ID of a fourth SAT connected to the third SAT, wherein the fourth SAT is a satellite from which the third SAT receives the first message or a satellite towards which the third SAT forwards the first message;

Determining the time delay corresponding to an ISL link between the fourth SAT and the third SAT according to the corresponding relation between the preconfigured ISL time delay and the satellite ID; and

the updating unit is configured to: and adding the delay corresponding to the ISL link between the fourth SAT and the third SAT to the delay corresponding to one or more ISLs experienced by the first message.
The SAT of any of claims 196-198, wherein the first message carries a second link delay of the UE to the first SAT.
The SAT of claim 215, wherein the link delay information is indicative of a total link delay from the UE to the third SAT,

the determination unit is configured to:

determining a first link delay of the first SAT to the third SAT; and

and determining the total link delay from the UE to the third SAT according to the first link delay and the second link delay.
The SAT of claim 216, wherein determining whether to forward the first message based on the link latency information comprises:

if the total link delay from the UE to the third SAT does not exceed the delay requirement of the target service, forwarding the first message; and/or

And if the total link delay from the UE to the third SAT exceeds the delay requirement of the target service, not forwarding the first message.
The SAT of claim 216, wherein the third SAT determines a first link delay of the first SAT to the third SAT from preconfigured information comprising at least one of:

the number of satellite hops corresponding to one or more satellite transmission paths from the first SAT to the third SAT;

ISL time delay corresponding to one or more satellite transmission paths from the first SAT to the third SAT;

one or more SATs corresponding to one or more satellite transmission paths from the first SAT to the third SAT.
The SAT of any one of claims 196-198, wherein the first message carries time information T1, the T1 indicating a time of day at which the UE sent a NAS request message for the target traffic.
The SAT of claim 219, the determining unit configured to:

determining time information T2, the T2 indicating a time at which the first message was received by the third SAT;

a total link delay from the UE to the third SAT is determined, wherein the total link delay is determined from a difference between the time information T2 and the time information T1.
The SAT of claim 220, the determining unit configured to:

forwarding the first message if the total link delay from the UE to the third SAT meets the delay requirement of the target service; and/or

And if the total link delay from the UE to the third SAT does not meet the delay requirement of the target service, not forwarding the first message.
The SAT of any of claims 196-199, wherein the first message is a NAS request message for the target traffic, the NAS request message originated by the UE.
The SAT of any of claims 196-218, wherein the first message comprises a NAS request message for the target traffic, the NAS request message originated by the UE.
The SAT of at least one of claims 219-221, wherein the first message comprises a NAS request message for the target traffic, the NAS request message originated by the UE, the NAS request message carrying the time information T1.
The SAT of at least one of claims 222-224, wherein the NAS request message comprises a service request for the target traffic or a PDU session establishment request for the target traffic.
The SAT of any one of claims 196-221, wherein the forwarding the first message comprises:

forwarding the first message to a next satellite; or (b)

Forwarding the first message to the network device.
The SAT of any of claims 196-221, wherein the network device is a core network element.
The SAT of claim 227, wherein the core network element is an access management function, AMF.
A method of communication in a non-terrestrial network NTN, the NTN providing communication with a network device for a user equipment UE through a plurality of SATs, the plurality of SATs including a first SAT, the first SAT being connected to the UE, the plurality of SATs including a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISLs, each ISL corresponding to one satellite hop, the method being applied to the first SAT, comprising:

receiving an NAS request message for a target service from the UE;

determining a satellite transmission path delay threshold allowed by the delay requirement of the target service; and

And sending a first message, wherein the first message comprises the allowed satellite transmission path delay threshold and the NAS request message.
The method of claim 229, wherein the allowed satellite transmission path delay threshold comprises: a number of satellite hops threshold; or an ISL latency threshold.
The method of claim 230, wherein the allowed satellite transmission path delay threshold is a number of satellite hops threshold, wherein determining the satellite transmission path delay threshold allowed by the delay requirement of the target traffic comprises:

and determining a threshold value of the number of satellite hops corresponding to the time delay requirement of the target service based on a mapping relation between the preconfigured target service time delay and the allowed number of satellite hops.
The method of claim 230, wherein the allowed satellite transmission path delay threshold is an ISL delay threshold, wherein determining the allowed satellite transmission path delay threshold for the delay requirement of the target service comprises:

and determining an ISL delay threshold corresponding to the delay requirement of the target service based on a mapping relation between the preconfigured target service delay and the allowed ISL delay.
The method of any one of claims 229-232, wherein the sending a first message includes: the first message is transmitted to a next SAT via a first satellite transmission path of the one or more satellite transmission paths.
The method of any of claims 229-233, wherein the NAS request message includes a service request for the target traffic or a PDU session establishment request for the target traffic.
The method of any of claims 229-234, wherein the first message further includes therein a satellite transmission path delay experienced by the first message, wherein the satellite transmission path delay experienced by the first message includes a number of hops of a satellite experienced by the first message or an ISL link delay experienced by the first message.
The method of claim 235, wherein the first message experiences a number of satellite hops of 0 or 1; the ISL link latency experienced by the first message includes or does not include an ISL latency of an ISL between the first SAT and a next SAT.
The method of any one of claims 229-234, wherein the network device is a core network element.
The method of claim 237, wherein the core network element is an access management function, AMF.
A satellite SAT located in a non-terrestrial network NTN, for performing a communication method in the NTN, the satellite SAT being a first SAT of a plurality of SATs included in the NTN, the NTN providing communication with a network device for a user equipment UE through the plurality of SATs, the first SAT being connected to the UE, the plurality of SATs including a second SAT, the second SAT being connected to the network device, one or more satellite transmission paths being present between the first SAT and the second SAT, wherein adjacent satellites in each satellite transmission path are connected by inter-satellite links ISL, each ISL corresponding to a satellite hop, the method comprising:

A receiving unit configured to receive a NAS request message for a target service from the UE;

a determining unit configured to determine a satellite transmission path delay threshold allowed by a delay requirement of the target service; and

a transmitting unit configured to transmit a first message, wherein the first message includes the allowed satellite transmission path delay threshold and the NAS request message.
The SAT of claim 239, wherein the allowed satellite transmission path delay threshold comprises: a number of satellite hops threshold; or an ISL latency threshold.
The SAT of claim 240, wherein the allowed satellite transmission path delay threshold is a number of satellite hops threshold, wherein determining the satellite transmission path delay threshold allowed by the delay requirement of the target traffic comprises:

and determining a threshold value of the number of satellite hops corresponding to the time delay requirement of the target service based on a mapping relation between the preconfigured target service time delay and the allowed number of satellite hops.
The SAT of claim 240, wherein the allowed satellite transmission path delay threshold is an ISL delay threshold, the determining unit configured to: and determining an ISL delay threshold corresponding to the delay requirement of the target service based on a mapping relation between the preconfigured target service delay and the allowed ISL delay.
The SAT of any of claims 239-242, the sending unit configured to: the first message is transmitted to a next SAT via a first satellite transmission path of the one or more satellite transmission paths.
The SAT of any of claims 239-243, wherein the NAS request message comprises a service request for the target traffic or a PDU session establishment request for the target traffic.
The SAT of any of claims 239-244, wherein the first message further comprises a satellite transmission path delay experienced by the first message, wherein the satellite transmission path delay experienced by the first message comprises a number of hops of a satellite experienced by the first message or an ISL link delay experienced by the first message.
The SAT of claim 245, wherein the first message experienced a number of satellite hops of 0 or 1; the ISL link latency experienced by the first message includes or does not include an ISL latency of an ISL between the first SAT and a next SAT.
The SAT of any of claims 239-244, wherein the network device is a core network element.
The SAT of claim 247, wherein the core network element is an access management function, AMF.
A satellite SAT located in a non-terrestrial network NTN, comprising: a processor and a memory having stored therein computer instructions that, when invoked and executed by the processor, cause the processor to perform the method of any one of claims 1-16, 33-42, 163-195, or 229-238.
A user equipment, UE, comprising: a processor and a memory having stored therein computer instructions which, when invoked and executed by the processor, cause the processor to perform the method of any of claims 53-68 or 85-99.
A network device, comprising: a processor and a memory having stored therein computer instructions that, when invoked and executed by the processor, cause the processor to perform the method of any one of claims 115-138.
A computer readable storage medium having stored thereon computer instructions which, when executed by a processor, cause the processor to perform the method of any one of claims 1-16, 33-42, 163-195, or 229-238.
A computer readable storage medium having stored thereon computer instructions which, when executed by a processor, cause the processor to perform the method of any of claims 53-68 or 85-99.
A computer readable storage medium having stored thereon computer instructions which, when executed by a processor, cause the processor to perform the method of any of claims 115-138.
A computer program product comprising computer instructions which, when executed by a processor, cause the processor to perform the method of any one of claims 1-16, 33-42, 163-195, or 229-238.
A computer program product comprising computer instructions which, when executed by a processor, cause the processor to perform the method of any of claims 53-68 or 85-99.
A computer program product comprising computer instructions which, when executed by a processor, cause the processor to perform the method of any of claims 115-138.