CN112492631B

CN112492631B - Switching method and device

Info

Publication number: CN112492631B
Application number: CN201910860098.0A
Authority: CN
Inventors: 王文; 谢振华
Original assignee: Vivo Mobile Communication Co Ltd
Current assignee: Vivo Mobile Communication Co Ltd
Priority date: 2019-09-11
Filing date: 2019-09-11
Publication date: 2023-10-31
Anticipated expiration: 2039-09-11
Also published as: CN112492631A

Abstract

The embodiment of the invention provides a switching method and equipment, wherein the method comprises the following steps: when a first terminal is switched from short-range direct communication interface communication to Uu interface communication, sending a second PDU session establishment request message to a service network of the first terminal; the anchor point of the second PDU session is a user plane function anchor point corresponding to a first PDU session, and when the first PDU session is a relay communication established between the first terminal and the second terminal, the second terminal is a relay PDU session established by the first terminal. In the embodiment of the invention, when the terminal is switched from the short-distance direct communication interface communication to the Uu interface communication, the service continuity of the terminal can be ensured, and the interruption delay of user experience is reduced.

Description

Switching method and device

Technical Field

The embodiment of the invention relates to the technical field of communication, in particular to a switching method and equipment.

Background

Referring to fig. 1a and 1b, the terminals in fig. 1a communicate with the base station through a Uu interface (communication interface between the terminals and the base station), and the terminals in fig. 1b communicate through a short-range direct communication interface (e.g., PC5 interface).

When a terminal needs to switch from short-range direct communication interface communication to Uu interface communication, how to ensure service continuity is a technical problem to be solved.

Disclosure of Invention

An object of the embodiments of the present invention is to provide a switching method and apparatus, which solve the problem of service continuity when a terminal is switched from a short-range direct communication interface to a Uu interface.

In a first aspect, an embodiment of the present invention provides a handover method, which is applied to a first terminal, including:

when the first terminal is switched from short-range direct communication interface communication to Uu interface communication, sending a request message for establishing a second protocol data unit PDU session to a service network of the first terminal;

the anchor point of the second PDU session is a user plane function anchor point corresponding to a first PDU session, and when the first PDU session is a relay communication established between the first terminal and the second terminal, the second terminal is a relay PDU session established by the first terminal.

In a second aspect, an embodiment of the present invention further provides a handover method, applied to a second terminal, including:

receiving a first request message from a first terminal, wherein the first request message is used for requesting to acquire the identification of the second terminal and/or the identification of a first PDU session;

a first request reply message is sent to the first terminal, the first request reply message comprises an identifier of the second terminal and/or an identifier of the first PDU session, and when the first PDU session establishes relay communication with the second terminal, the second terminal establishes relay PDU session for the first terminal;

Or,

and sending a switching command to a first terminal, wherein the switching command indicates the path switching of the first terminal.

In a third aspect, an embodiment of the present invention further provides a handover method, applied to a first network function, including:

receiving a request message for establishing a second PDU session sent by a first terminal;

In a fourth aspect, an embodiment of the present invention further provides a handover method, applied to a second network function, including:

receiving a second request message, and determining information related to a first PDU session according to the second request message, wherein when the first PDU session is a relay communication established between a first terminal and a second terminal, the second terminal is a relay PDU session established by the first terminal;

transmitting a second request reply message, the second request reply message comprising: the information related to the first PDU session;

or,

In a fifth aspect, the present invention further provides a handover method, applied to a third network function, including:

receiving a context setup request message for the second PDU session from the first network function;

In a sixth aspect, an embodiment of the present invention further provides a handover method, applied to a fourth network function, including:

In a seventh aspect, the present invention further provides a handover method, applied to a fourth network function, including:

receiving a change request message of the first PDU session from a third network function;

transmitting a change request reply message of the first PDU session to the third network function;

And when the first PDU session is established by the first terminal and the second terminal, the second terminal establishes a relay PDU session for the first terminal.

In an eighth aspect, an embodiment of the present invention further provides a handover method, applied to a fourth network function, including:

receiving a context setup request message for the second PDU session from the third network function;

establishing an N4 session context of a second PDU session with a fifth network function serving as an anchor point of the first PDU session;

sending a context setup request reply message for the second PDU session to the third network function;

In a ninth aspect, an embodiment of the present invention further provides a handover method, applied to a fourth network function, including:

receiving a context acquisition request message for a second PDU session from a third network function, the third network function being configured to establish the second PDU session;

Sending a context acquisition reply message of the second PDU session to the third network function;

receiving a change request message for a first PDU session from the third network function;

In a tenth aspect, an embodiment of the present invention further provides a first terminal, including:

a first sending module, configured to send a request message for establishing a second PDU session to a service network of the first terminal when the first terminal switches from short-range direct communication interface communication to Uu interface communication;

the anchor point of the second protocol data unit PDU session is a user plane function anchor point corresponding to a first PDU session, and when the first PDU session is a relay communication established between the first terminal and a second terminal, the second terminal is a relay PDU session established by the first terminal.

In an eleventh aspect, an embodiment of the present invention further provides a second terminal, including:

A third receiving module, configured to receive a first request message from a first terminal, where the first request message is used to request to obtain an identifier of the second terminal and/or an identifier of a first PDU session;

a fourth sending module, configured to send a first request reply message to the first terminal, where the first request reply message includes an identifier of the second terminal and/or an identifier of the first PDU session, where the first PDU session is a relay PDU session established by the second terminal when the first terminal establishes relay communication with the second terminal;

or,

and the fifth sending module is used for sending a switching command to the first terminal, wherein the switching command indicates the path switching of the first terminal.

In a twelfth aspect, an embodiment of the present invention further provides a first network function, including:

a fifth receiving module, configured to receive a request message for establishing a second PDU session sent by the first terminal;

In a thirteenth aspect, an embodiment of the present invention further provides a second network function, including:

a seventh receiving module, configured to receive a second request message, determine information related to a first PDU session according to the second request message, where the first PDU session is a relay PDU session established by a first terminal and a second terminal when the second terminal establishes relay communication with the first terminal;

an eighth sending module, configured to send a second request reply message, where the second request reply message includes: the information related to the first PDU session;

or,

and the ninth sending module is used for sending a switching command to the first terminal, wherein the switching command indicates the path switching of the first terminal.

In a fourteenth aspect, an embodiment of the present invention further provides a third network function, including:

a tenth receiving module for receiving a context setup request message of the second PDU session from the first network function;

the anchor point of the second PDU session is a user plane function anchor point corresponding to a first PDU session, when the first PDU session is a relay communication established between the first terminal and a second terminal, the second terminal is a relay PDU session established by the first terminal, and the third network function is used for establishing the second PDU session.

In a fifteenth aspect, an embodiment of the present invention further provides a fourth network function, including:

a fifteenth receiving module for receiving a context setup request message for the second PDU session from the first network function;

In a sixteenth aspect, an embodiment of the present invention further provides a fourth network function, including:

a seventeenth receiving module for receiving a change request message of the first PDU session from the third network function;

a sixteenth sending module, configured to send a change request reply message of the first PDU session to the third network function;

In a seventeenth aspect, an embodiment of the present invention further provides a fourth network function, including:

a nineteenth receiving module configured to receive a context setup request message for the second PDU session from the third network function;

An eighth establishing module, configured to use a fifth network function as an anchor point of a second PDU session, and establish an N4 session context of the second PDU session with the fifth network function;

an eighteenth sending module, configured to send a context setup request reply message of the second PDU session to the third network function;

In an eighteenth aspect, an embodiment of the present invention further provides a fourth network function, including:

a twenty-first receiving module, configured to receive a context acquisition request message of a second PDU session from a third network function, where the third network function is configured to establish the second PDU session;

a twentieth transmitting module, configured to send a context acquisition reply message of the second PDU session to the third network function;

a twenty-second receiving module, configured to receive a change request message of a first PDU session from the third network function;

a twenty-first transmitting module, configured to transmit a change request reply message of the first PDU session to the third network function;

In a nineteenth aspect, an embodiment of the present invention further provides a terminal, including: a processor, a memory and a program stored on the memory and executable on the processor, which when executed by the processor implements the steps of the handover method as described above.

In a twentieth aspect, an embodiment of the present invention further provides a network device, including: a processor, a memory and a program stored on the memory and executable on the processor, which when executed by the processor implements the steps of the handover method as described above.

In a twenty-first aspect, embodiments of the present invention also provide a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements the steps of the handover method as described above.

In the embodiment of the invention, when the terminal is switched from the short-distance direct communication interface communication to the Uu interface communication, the service continuity of the terminal can be ensured, and the interruption delay of user experience is reduced.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to designate like parts throughout the figures. In the drawings:

FIGS. 1a and 1b are schematic diagrams of prior paths;

FIG. 2 is a diagram of a conventional data link;

FIG. 3 is a schematic diagram of a conventional control link;

fig. 4 is a flowchart of a handover method at a first terminal according to an embodiment of the present invention;

fig. 5 is a flowchart of a handover method at a second terminal side according to an embodiment of the present invention;

fig. 6 is a flowchart of a handover method at a first network function side according to an embodiment of the present invention;

fig. 7 is a flowchart of a handover method at a second network function side according to an embodiment of the present invention;

fig. 8 is a flowchart of a handover method at a third network function side according to an embodiment of the present invention;

fig. 9 is a flowchart of a handover method at a fourth network function side according to an embodiment of the present invention;

fig. 10 is a second flowchart of a handover method at a fourth network function side according to an embodiment of the present invention;

fig. 11 is a third flowchart of a handover method at a fourth network function side according to an embodiment of the present invention;

Fig. 12 is a flowchart of a handover method at a fourth network function side according to an embodiment of the present invention;

FIG. 13 is a flowchart of a switching method according to an embodiment of the present invention;

FIG. 14 is a second flowchart of a switching method according to an embodiment of the invention;

FIG. 15 is a third flowchart of a switching method according to an embodiment of the invention;

FIG. 16 is a fourth flowchart of a switching method according to an embodiment of the present invention;

FIG. 17 is a fifth flowchart of a switching method according to an embodiment of the present invention;

FIG. 18 is a flowchart of a switching method according to an embodiment of the present invention;

FIG. 19 is a flowchart of a switching method according to an embodiment of the present invention;

FIG. 20 is a flowchart eighth of a handover method according to an embodiment of the present invention;

FIG. 21 is a flowchart of a handover method according to an embodiment of the present invention;

fig. 22 is a schematic structural diagram of a first terminal according to an embodiment of the present invention;

fig. 23 is a schematic structural diagram of a second terminal according to an embodiment of the present invention;

fig. 24 is a schematic structural diagram of a first network function according to an embodiment of the present invention;

fig. 25 is a schematic structural diagram of a second network function according to an embodiment of the present invention;

fig. 26 is a schematic structural diagram of a third network function according to an embodiment of the present invention;

FIG. 27 is a schematic diagram of a fourth network function according to an embodiment of the present invention;

FIG. 28 is a second diagram illustrating a fourth network function according to an embodiment of the present invention;

FIG. 29 is a third diagram illustrating a fourth network function according to an embodiment of the present invention;

FIG. 30 is a fourth schematic diagram of a fourth network function according to an embodiment of the present invention;

fig. 31 is a schematic diagram of a terminal according to an embodiment of the present invention;

fig. 32 is a schematic diagram of a network device according to an embodiment of the present invention.

Detailed Description

In order to facilitate understanding of the embodiments of the present invention, several technical points are described below:

technical point 1: network Control Interaction Service (NCIS).

With the development of some new forms of devices (e.g., virtual Reality (VR)/augmented Reality (Augmented Reality, AR) devices, robots, etc.) or some new technologies (e.g., AR and VR), new services in which people exchange information and play games will become more popular.

Many interactive services occur in local areas, such as home meetings or bar entertainment, or office education, through specific direct links or indirect links between users, which can enhance the requirements for throughput, latency, reliability and resource/power utilization.

For NCIS services, the data chain shown in fig. 1a and 1b may be used as a baseline, where fig. 1a is a 5G core network (5G Core Network,5GC) path (path) and fig. 1b is a proximity-based service communication path (ProSe Communication path).

For NCIS services, the data link may be a combination of the two approaches described above in fig. 1a and 1b, as shown in fig. 2, in order to improve throughput and rigid latency.

For NCSI services, the control link shown in fig. 3 may be used as a baseline, in which case important control signaling comes from the network and some auxiliary signaling on the straight link may be interacted between users.

An interactive service refers to a service for exchanging data between interested users in the same NCIS session, such as an interactive game, data sharing between various terminals (e.g., user Equipment (UE), robots, etc.), etc. The NCIS session herein means that all terminals in the session can share the same context, update the same service information, and complete the session at the same time. Which terminals in the same NCIS session will be classified into one NCIS group. The interactive services here are real-time, requiring high throughput and low latency. Terminals joining the NCIS session may be local or remote from each other, may be from the same mobile network operator (Mobile Network Operator, MNO), or may be from different MNOs. The use case describes a scenario in which a set of terminals supporting the NCIS service can discover each other, initiate NCIS sessions, and exchange data.

Technical point 2: relay (Relay).

The relay technology in the wireless communication system is to add one or more relay nodes between the base station and the terminal, and is responsible for forwarding the wireless signal once or more times, i.e. the wireless signal can reach the terminal only through multiple hops.

The wireless relay technology not only can be used for expanding cell coverage and compensating cell coverage blind points, but also can improve cell capacity through space resource multiplexing. For indoor coverage, the relay technology can also play a role in overcoming penetration loss and improving indoor coverage quality.

Taking a simpler two-hop relay as an example, the wireless relay divides a base station-terminal link into two links of a base station-relay station and a relay station-terminal, so that a link with poor quality is replaced by two links with good quality, and higher link capacity and better coverage are obtained.

Currently, a relay supported in long term evolution (Long Term Evolution, LTE) is a UE-to-network relay (UE-to-network relay), that is, a relay has one end connected to a UE and one end connected to a network side. The UE connected to the relay is called remote UE (remote UE).

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus. Furthermore, the use of "and/or" in the specification and claims means at least one of the connected objects, e.g., a and/or B, meaning that it includes a single a, a single B, and that there are three cases of a and B.

In embodiments of the application, words such as "exemplary" or "such as" are used to mean serving as an example, instance, or illustration. Any embodiment or design described herein as "exemplary" or "e.g." in an embodiment should not be taken as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "such as" is intended to present related concepts in a concrete fashion.

The techniques described herein are not limited to long term evolution (Long Time Evolution, LTE)/LTE evolution (LTE-Advanced, LTE-a) systems and may also be used for various wireless communication systems such as code division multiple access (Code Division Multiple Access, CDMA), time division multiple access (Time Division Multiple Access, TDMA), frequency division multiple access (Frequency Division Multiple Access, FDMA), orthogonal frequency division multiple access (Orthogonal Frequency Division Multiple Access, OFDMA), single-carrier frequency division multiple access (Single-carrier Frequency-Division Multiple Access, SC-FDMA), and other systems.

The terminals described herein may be cell phones, tablet computers, notebook computers, ultra mobile personal computers (Ultra-Mobile Personal Computer, UMPC), netbooks or personal digital assistants (Personal Digital Assistant, PDA), mobile internet appliances (Mobile Internet Device, MID), wearable devices, or in-vehicle devices, among others.

The terms "system" and "network" are often used interchangeably. A CDMA system may implement radio technologies such as CDMA2000, universal terrestrial radio access (Universal Terrestrial Radio Access, UTRA), and the like. UTRA includes wideband CDMA (Wideband Code Division Multiple Access, WCDMA) and other CDMA variants. TDMA systems may implement radio technologies such as the global system for mobile communications (Global System for Mobile Communication, GSM). OFDMA systems may implement radio technologies such as ultra mobile broadband (Ultra Mobile Broadband, UMB), evolved UTRA (E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, flash-OFDM, and the like. UTRA and E-UTRA are parts of the universal mobile telecommunications system (Universal Mobile Telecommunications System, UMTS). LTE and higher LTE (e.g., LTE-a) are new UMTS releases that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-a and GSM are described in the literature from an organization named "third generation partnership project" (3rd Generation Partnership Project,3GPP). CDMA2000 and UMB are described in the literature from an organization named "third generation partnership project 2" (3 GPP 2). The techniques described herein may be used for the systems and radio technologies mentioned above as well as for other systems and radio technologies.

Referring to fig. 4, an embodiment of the present invention provides a handover method, where an execution body of the method is a first terminal, including the steps of: 401.

step 401: when the first terminal needs to switch from short-distance direct communication interface communication to Uu interface communication, sending a second PDU session establishment request message to a service network of the first terminal;

the anchor point of the second protocol data unit (Protocol Data Unit, PDU) session is a user plane function anchor point corresponding to a first PDU session, and when the first PDU session establishes relay communication with a second terminal, the second terminal establishes (special) relay PDU session for the first terminal.

The first terminal may also be referred to as Remote UE (hereinafter referred to as Re UE).

The second terminal may also be referred to as a Relay UE (hereinafter referred to as Rl UE).

The above-mentioned need for the first terminal to switch from short-range direct communication interface (hereinafter, PC5 interface is taken as an example) communication to Uu interface communication may refer to that the first terminal needs to switch from ProSe communication path to 5GC path, and it is understood that the switching scenario includes, but is not limited to, network control interaction service.

Taking the network control interactive service as an example, from the network perspective, both the ProSe communication path and the 5GC path can satisfy the VR-based interactive service, and the network can determine whether the ProSe communication path or the 5GC path should be used according to the interactive service requirement. For example, when the UE is in coverage and the service requirements, for example: the data rate may be satisfied and the network may use a 5GC path; although the UE is in coverage, the service requirements are not met, for example: the data rate is not met and the network may use the ProSe communication path.

The above-mentioned establishment request message for transmitting the second PDU session to the service network of the first terminal may refer to: an access and mobility management function (Access and Mobility Management Function, AMF) of the first terminal is sent a second PDU session setup request message.

The first PDU session described above may also be referred to as a relay PDU session.

In some embodiments, prior to step 401, the method shown in fig. 4 may further comprise: sending a first request message, where the first request message is used to request to obtain an identifier of the second terminal and/or an identifier of the first PDU session, and optionally, the identifier of the second terminal may be a fifth generation mobile communication technology-globally unique temporary terminal identifier (hereinafter abbreviated as 5G-GUTI) of the second terminal; a first request reply message is received, the first request reply message comprising an identification of the second terminal and/or an identification of the first PDU session.

The above-described flow of transmitting the first request message and receiving the first request reply message may refer to the first embodiment described below.

In some embodiments, prior to step 401, the method shown in fig. 4 may further comprise: a handover command is received from a service network of the second terminal, such as an AMF (relay AMF) of a service of the second terminal, or the second terminal, the handover command indicating the first terminal path handover. Further, after receiving the handover command, a handover command reply message may also be sent to the service network of the second terminal (e.g. the service AMF of the second terminal) or the second terminal.

The above-described flow of receiving a handover command from the service AMF of the second terminal and the flow of receiving a handover command from the second terminal can refer to the second embodiment described below.

In some implementations, the handover command includes one or more of: (1) an identification of the second terminal; (2) an identification of the first PDU session; (3) The IP address of the first terminal, when the IP address of the first terminal is the IP address allocated to the first terminal by the second terminal when the second terminal establishes connection with the first terminal.

In some embodiments, the setup request message for the second PDU session may include one or more of the following: (1) an identification of the second terminal; (2) an identification of the first PDU session; (3) an identification of a second PDU session; (4) the IP address of the first terminal.

In the embodiment of the invention, after the remote terminal is switched from the short-distance direct communication interface communication to the Uu port communication, the service continuity of the remote terminal can be ensured, and the interruption delay of user experience is reduced.

Referring to fig. 5, an embodiment of the present invention further provides a handover method, where an execution body of the method is a second terminal, including: step 501 and step 502, or step 503.

Step 501: receiving a first request message from a first terminal, wherein the first request message is used for requesting to acquire the identification of a second terminal and/or the identification of a first PDU session;

Step 502: transmitting a first request reply message to the first terminal, wherein the first request reply message comprises: the identity of the second terminal and/or the identity of the first PDU session, the IP address of the first terminal. And when the first PDU session is established by the first terminal and the second terminal, the second terminal establishes a relay PDU session for the first terminal.

The above-described steps 501 and 502 may refer to the first embodiment described below.

Step 503: and sending a switching command to the first terminal, wherein the switching command indicates the path switching of the first terminal.

The above step 503 may refer to the second embodiment described below.

In some embodiments, the method shown in fig. 5 may further comprise: a handover command reply message is received from the first terminal.

In the embodiment of the invention, when the remote terminal is switched from the short-distance direct communication interface communication to the Uu port communication, the service continuity of the remote terminal can be ensured, and the interruption delay of user experience is reduced.

Referring to fig. 6, an embodiment of the present invention further provides a handover method, where an execution body of the handover method is a first network function, for example, an AMF serving a first terminal, including: step 601.

Step 601: receiving a request message for establishing a second PDU session sent by a first terminal;

the anchor point of the second PDU session is a user plane function anchor point corresponding to the first PDU session, and when the first PDU session is a relay communication established between the first terminal and the second terminal, the second terminal establishes a relay PDU session for the first terminal.

The first network function may also be referred to as Remote AMF (Rm AMF).

In some embodiments, the method shown in fig. 6 may further comprise: a second request message is sent to the second network function requesting the second network function to provide information related to the first PDU session. Further, a second request reply message is received from the second network function, the second request reply message comprising: information related to the first PDU session.

The second network function may be an AMF serving the second terminal, which may also be referred to as relay AMF (Relay AMF).

In some implementations, the information related to the first PDU session or the second request reply message may include one or more of: (1) An identification of a fourth network function (also referred to as a relay SMF ID, hereinafter referred to as Rl SMF ID), the fourth network function being configured to establish a first PDU session; (2) A context identification (which may also be referred to as relay SM context ID) of the first PDU session; (3) An identity of a fifth network function, which is an anchor point for the first PDU session, which may also be referred to as a relay user plane function anchor point (relay UPF anchor).

It will be appreciated that when the information related to the first PDU session and the identifier of the fifth network function are included in the second request reply message, the implementation may refer to the first embodiment described below; when the information related to the first PDU session and the identifier of the fifth network function are not included in the second request reply message, the implementation may refer to the second embodiment described below. In some implementations, the second request message can include one or more of the following: (1) An identification of the second terminal, (2) an identification of the first PDU session.

In some embodiments, the second request reply message includes: identification of the fourth network function, the method shown in fig. 6 may further include: a third network function is selected based on an identification (Rl SMF ID) of a fourth network function, the third network function being used to establish the second PDU session. That is, rl SMF is selected as Rm SMF.

The third network function may also be called Remote SMF (hereinafter referred to as Rm SMF), where Rm SMF is selected according to the Rl SMF ID, that is, rl SMF is selected as Rm SMF.

In some embodiments, the method shown in fig. 6 may further comprise: a third network function is selected based on a selection policy of a session management function, the third network function being configured to establish the second PDU session. That is, the Rm SMF selected is not Rl SMF.

In some embodiments, the method shown in fig. 6 may further comprise: a context setup request message for the second PDU session is sent to the third network function.

Optionally, the context setup request message of the second PDU session includes one or more of: (1) a second PDU session identification; (2) a first PDU session identification; (3) The IP address of the first terminal is the IP address distributed to the first terminal by the second terminal when the second terminal establishes connection with the first terminal; (4) identification of a fourth network function; (5) identification of a fifth network function.

In the embodiment of the invention, when the remote terminal is switched from short-distance direct communication interface communication to Uu port communication, the network selects the UPF anchor point corresponding to the relay PDU session as the UPF anchor point for establishing the PDU session on the Uu port, thereby ensuring the service continuity of the remote terminal and reducing the interruption delay of user experience.

Referring to fig. 7, an embodiment of the present invention further provides a handover method, where an execution body of the handover method is a second network function, and the second network function may also be called a Relay AMF (hereinafter referred to as Rl AMF), including: steps 701 to 702, or step 703.

Step 701: receiving a second request message, and determining information related to a first PDU session according to the second request message, wherein when the first PDU session is a relay communication established between a first terminal and a second terminal, the second terminal is a relay PDU session established by the first terminal;

Step 702: transmitting a second request reply message, the second request reply message comprising: the information related to the first PDU session.

The above steps 701 and 702 can refer to the first embodiment described below.

Step 703: and sending a switching command to a first terminal, wherein the switching command indicates the path switching of the first terminal.

The above step 703 may refer to the second embodiment described below.

In some embodiments, after step 703, the method shown in fig. 7 may further include: and receiving a switching command reply message from the first terminal.

In some implementations, the information related to the first PDU session can include one or more of: (1) An identification of a fourth network function (Rl SMF ID), the fourth network function being configured to establish the first PDU session; (2) a context identification of the first PDU session; (3) An identification of a fifth network function, the fifth network function being an anchor point for the first PDU session.

In some embodiments, prior to step 702, the method shown in fig. 7 may further comprise: and sending a third request message to the fourth network function (Rl SMF), wherein the third request message is used for requesting the fourth network function to provide the identifier (Rl UPF Anchor ID) of the fifth network function. Further, a third request reply message is received, the third request reply message comprising an identification of the fifth network function.

In some implementations, the third request message can include one or more of the following: (1) a context identification of the first PDU session; (2) an identification of the first PDU session. Wherein the identification of the first PDU session is selectable.

Referring to fig. 8, an embodiment of the present invention further provides a handover method, where an execution body of the handover method is a third network function, and the third network function may be called Remote SMF (Rm SMF), including: step 801.

Step 801: receiving a context setup request message for the second PDU session from the first network function;

the anchor point of the second PDU session is a user plane function anchor point corresponding to the first PDU session, when the first PDU session is a relay communication established between the first terminal and the second terminal, the second terminal establishes a relay PDU session for the first terminal, and the third network function is used for establishing the second PDU session.

The third network function (Rm SMF) may be selected by the first network function based on an SMF selection method, and the third network function is not a fourth network function (Rl SMF).

In some embodiments, after step 801, the method shown in fig. 8 may further include:

establishing an N4 session context of the second PDU session with a fifth network function (relay UPF anchor) serving as an anchor point of the first PDU session;

transmitting a change request message of the first PDU session to a fourth network function (Rl SMF) for establishing the first PDU session;

receiving a change request reply message of the first PDU session from the fourth network function, and then completing a subsequent second PDU session establishment procedure.

In some embodiments, prior to step 801, the method shown in fig. 8 may further comprise: a user plane function selection procedure is initiated to select a sixth network function (hereinafter referred to as I-rm_upf, intermediate UPF) that is the intermediate UPF of the second PDU session. Further, an N4 session context for the second PDU session is established with the sixth network function.

The above flow can be referred to example 3 in embodiment one.

initiating a user plane function selection process, and selecting a sixth network function, wherein the sixth network function is an intermediate UPF of the second PDU session;

establishing an N4 session context for the second PDU session with the sixth network function;

sending a context establishment request message of the second PDU session to a fourth network function, the fourth network function being configured to establish the first PDU session;

a context setup reply message for the second PDU session is received from the fourth network function.

sending a context acquisition request message of the first PDU session to a fourth network function, wherein the fourth network function is used for establishing the first PDU session;

Receiving a context acquisition request reply message for the first PDU session from the fourth network function;

establishing an N4 session context of the second PDU session with the fifth network function, the fifth network function being an anchor point for the first PDU session;

transmitting a change request message of the first PDU session to the fourth network function;

a change request reply message for the first PDU session is received from the fourth network function.

In some embodiments, before establishing the N4 session context of the second PDU session with the fifth network function, the method further comprises:

and initiating a user plane function selection process, and selecting a sixth network function, wherein the sixth network function is the intermediate UPF of the second PDU session.

In some embodiments, the method further comprises: an N4 session context for the second PDU session is established with the sixth network function.

The above flow can be referred to example 3 and example 4 in the second embodiment.

In some implementations, the change request message of the first PDU session may include one or more of the following: (1) a context identification of the first PDU session; (2) The IP address of the first terminal is the IP address distributed to the first terminal by the second terminal when the second terminal establishes connection with the first terminal; (3) identification of a fifth network function (Rl UPF anchor).

In some embodiments, the context setup request message of the second PDU session may include one or more of the following: (1) a second PDU session identification; (2) a first PDU session identification; (5) The IP address of the first terminal is the IP address distributed to the first terminal by the second terminal when the second terminal establishes connection with the first terminal; (6) identification of a fourth network function; (6) identification of a fifth network function.

Referring to fig. 9, an embodiment of the present invention further provides a handover method, where an execution body of the handover method is a fourth network function, and the fourth network function may also be called a Relay SMF (hereinafter referred to as Rl SMF), including: step 901.

Step 901: receiving a context setup request message for the second PDU session from the first network function;

In the embodiment of the present invention, the first network function selects a network function corresponding to the fourth network function (Rl SMF) identifier as the third network function (Rm SMF).

In some embodiments, prior to step 901, the method shown in fig. 9 may further include:

receiving a third request message from a second network function, wherein the third request message is used for requesting the fourth network function to provide an identifier of a fifth network function, and the fifth network function is an anchor point of the first PDU session;

and sending a third request reply message to the second network function, wherein the third request reply message comprises the identification of the fifth network function.

In some embodiments, the third request message includes one or more of the following: (1) a context identification of the first PDU session; (2) an identification of the first PDU session.

In some embodiments, after receiving the context setup request message for the second PDU session from the first network function, the method further comprises: and using the fifth network function as an anchor point of the second PDU session, and establishing an N4 session context of the second PDU session with the fifth network function.

In some embodiments, after receiving the context setup request message for the second PDU session from the first network function, the method further comprises:

In some embodiments, after receiving the context setup request message for the second PDU session from the first network function, the method further comprises: and initiating a change process of the first PDU session, and then completing a subsequent second PDU session establishment process.

The above flow may refer to example 2 of embodiment one and example 1 of embodiment two described below.

Referring to fig. 10, an embodiment of the present invention further provides a handover method, where an execution body of the handover method is a fourth network function (Rl SMF), including: step 1001 and step 1002.

Step 1001: receiving a change request message of the first PDU session from a third network function;

Step 1002: transmitting a change request reply message of the first PDU session to a third network function;

The above flow can be referred to examples 1 and 4 of the first embodiment and example 4 of the second embodiment described below.

In some embodiments, after receiving the change request message of the first PDU session from the third network function, the method further comprises: initiating a change procedure for the first PDU session.

In some embodiments, the method further comprises: receiving a third request message from a second network function, wherein the third request message is used for requesting the fourth network function to provide an identifier of a fifth network function, and the fifth network function is an anchor point of the first PDU session;

Referring to fig. 11, an embodiment of the present invention further provides a handover method, where an execution body of the handover method is a fourth network function (Rl SMF), including: steps 1101 to 1103.

Step 1101: receiving a context setup request message for the second PDU session from the third network function;

step 1101: establishing an N4 session context of a second PDU session with a fifth network function serving as an anchor point of the first PDU session;

step 1103: sending a context setup request reply message for the second PDU session to the third network function;

The above flow can be referred to example 3 of the first embodiment described below, and example 3 of the second embodiment.

In some embodiments, prior to receiving the context setup request message for the second PDU session from the third network function, the method further comprises:

In some embodiments, after establishing the N4 session context of the second PDU session with a fifth network function, the method further comprises: a modification procedure of the first PDU session is initiated and a subsequent second PDU session establishment procedure may then be completed.

Referring to fig. 12, an embodiment of the present invention further provides a handover method, where an execution body of the handover method is a fourth network function (Rl SMF), including: steps 1201 to 1204.

Step 1201: receiving a context acquisition request message for a second PDU session from a third network function, the third network function being configured to establish the second PDU session;

step 1202: sending a context acquisition reply message of the second PDU session to the third network function;

step 1203: receiving a change request message for a first PDU session from the third network function;

step 1204: transmitting a change request reply message of the first PDU session to the third network function;

The above flow can be referred to example 4 of the first embodiment described below, and example 4 of the second embodiment.

In some embodiments, after receiving the change request message of the first PDU session from the third network function, the method further comprises:

A modification procedure of the first PDU session is initiated and a subsequent second PDU session establishment procedure may then be completed.

Referring to fig. 13, a flow of a handover method is illustrated, and specific steps are as follows:

step 1: the relay data stream is transmitted between the remote terminal and the relay terminal and between the relay terminal and a relay PDU session UPF anchor point;

step 2: the relay UE identifier and the relay PDU session identifier are transmitted between the remote terminal and the relay terminal and between the relay terminal and the relay terminal service network;

step 3: the remote terminal sends PDU establishment request to the remote terminal service network;

step 4: transmitting relay PDU session context information between a remote terminal service network and a relay terminal service network;

step 5: the remote terminal service network selects a UPF anchor point of the relay PDU session;

step 6: establishing an N4 session between a remote terminal service network and a relay PDU session UPF anchor point;

Step 7: the remote terminal service network replies PDU establishment acceptance to the remote terminal;

step 8: and transmitting data flow between the remote terminal and the UPF anchor point of the relay PDU session.

In the embodiment of the invention, when the remote terminal is switched from the PC5 interface to the Uu interface, the UPF anchor point is not changed. Namely, when the remote terminal is switched to the Uu port, the UPF anchor point of the established PDU session selects the UPF anchor point corresponding to the relay PDU session, thereby ensuring the service continuity of the remote terminal and reducing the interruption delay of user experience.

The following describes the implementation of the embodiment of the present invention in conjunction with examples 1 to 4 of the first embodiment and examples 1 to 4 of the second embodiment.

Embodiment one: the remote terminal, the remote AMF or the remote SMF requests to acquire the relay PDU session information and/or the relay network element function information of the relay network.

Example 1: rm_AMF performs SMF selection (via unified data repository (Unified Data Repository, UDR) selection), selecting one Rm_SMF (SMF corresponding to non-Rl SMF ID).

Referring to fig. 14, the specific steps are as follows:

step 0a: a relay UE (hereinafter referred to as rl_ue) has established a dedicated relay PDU session (relay PDU session, hereinafter referred to as Rl PDU session) for a remote UE (hereinafter referred to as rm_ue), which session is identified with Rl PDU session ID.

Step 0b: rm_UE starts path switching;

optionally, the condition triggering the path switch may include one or more of:

(1) The Rm_UE application layer triggers path switching;

(2) The Rm_UE AS layer indicates that the quality of the PC5 link is poor;

(3) A handover indication or command trigger of a relay network (e.g., relay AMF (hereinafter referred to as rl_amf)) is received.

Step 1: rm_UE sends a first request message to Rl_UE;

optionally, the first request message is for requesting one or more of: (1) 5G-GUTI for rl_ue (hereinafter referred to as Rl 5G-GUTI) and (2) Rl PDU session ID, wherein the english full name Globally Unique Temporary UE Identity for GUTI, chinese meaning is globally unique temporary UE identity.

Step 2: the Rl_UE sends a first request reply message to the Rm_UE.

Optionally, the first request reply message may include one or more of the following: (1) Rl 5G-GUTI and (2) Rl PDU session ID; further, the first request reply message may further include: rm_UE related quality of service (Quality of Service, qoS) Flow identification (QoS Flow ID, QFI).

Step 3: rm_UE initiates PDU session Establishment (Establishment) procedure and sends PDU session Establishment request message to AMF served by Rm_UE (hereinafter Rm_AMF).

Optionally, the PDU session establishment request message may include one or more of the following: (1) Rm_UE establishes Rm PDU session identification (Rm PDU session ID) in a remote UE service network, (2) Rl 5G-GUTI and (3) Rl PDU session ID, and further, the PDU session establishment request message may further include: QFI.

Step 4: rm_AMF searches Rl_AMF according to Rl 5G-GUTI, and sends a second request message to Rl_AMF according to the search result.

Optionally, the second request message may be used to request that the Rl-AMF provide the Rl PDU session context information (hereinafter referred to as Rl SM context).

Optionally, the second request message may include one or more of: (1) Rl 5G-GUTI and (2) Rl PDU session ID.

Step 5: the rl_amf retrieves a relay SMF identity (hereinafter referred to as rl_smf ID) and/or a relay session context identity (hereinafter referred to as Rl SM context ID) of the Rl PDU session based on the Rl 5G-GUTI and/or Rl PDU session ID, and sends a third request message to the rl_smf.

Optionally, the third request message is used to request the rl_smf to provide the UPF anchor point identification of the Rl PDU session (hereinafter referred to as rl_upf anchor ID)

Optionally, the third request message may include: the Rl SM context ID, further, the third request message may further include: rl PDU session ID.

Step 6: the Rl_SMF retrieves the Rl_UPF anchor ID according to the Rl SM context ID and sends a third request reply message to the Rl_AMF.

Optionally, the third request reply message may include: rl_UPF Anchor ID.

Step 7: the rl_amf sends a second request reply message to the rm_amf.

Optionally, the second request reply message may include one or more of the following: (1) Rl_SMF ID, (2) Rl SM context ID, and (3) Rl_UPF anchor ID.

Step 8: rm_AMF selects one Rm_SMF.

For example, rm_amf performs SMF selection (through UDR selection), and selects one rm_smf (SMF corresponding to a non-Rl SMF ID).

Step 9: rm_AMF sends PDU session context setup request message to Rm_SMF.

Optionally, the PDU session context setup request message may include one or more of the following: (1) rl_smf ID, (2) Rl SM context ID, (3) rm_ue IP, further, the PDU session context setup request message may further include: (4) Rl UPF Anchor ID.

Step 10: rm_SMF selects an intermediate UPF (denoted as I-Rm_UPF).

In some embodiments, step 10 is an optional step.

Step 11a: rm_SMF establishes an N4 session context for Rm PDU session with I-Rm_UPF.

In some embodiments, step 11 is an optional step.

Step 11b: rm_SMF retrieves Rl UPF anchor based on Rl UPF anchor ID, rm_SMF establishes N4 session context of Rm PDU session with Rl UPF anchor (Rl UPF corresponding to Rl UPF anchor ID).

Step 12: rm_SMF sends a relay PDU session (Rl PDU session) change request to Rl SMF.

Optionally, a PDU session change (Modification) request is used for an Rl SMF to change an Rl PDU session.

Optionally, the PDU session change request may include one or more of the following: (1) The Rl SM context ID, (2) rm_ue IP, further, the PDU session change request may further include: rl UPF Anchor ID.

Step 13: the rl_smf initiates the Rl PDU session change procedure.

In some embodiments, step 13 is an optional step.

Step 14: the rl_smf sends a relay PDU session change request reply message to the rm_smf.

Step 15: rm_smf continues with the subsequent Rm PDU session Establishment process.

It will be appreciated that the Rm PDU session Establishment process is an existing process and will not be described here.

Example 2: rm_AMF selects SMF corresponding to Rl_SMF ID.

Referring to fig. 15, the specific steps are as follows:

Step 0b: rm_UE starts path switching;

(1) The Rm_UE application layer triggers path switching;

(2) The Rm_UE AS layer indicates that the quality of the PC5 link is poor;

(3) A handover indication or command trigger of the relay network (rl_amf) is received.

Step 1: rm_UE sends a first request message to Rl_UE;

Step 2: the Rl_UE sends a first request reply message to the Rm_UE.

Optionally, the third request reply message may include: rl_UPF Anchor ID.

In some embodiments, step 5 and step 6 are optional steps.

Step 7: the rl_amf sends a second request reply message to the rm_amf.

Step 8: rm_AMF sends PDU session context setup request message to Rl_SMF.

Step 9: rl_SMF selects an intermediate UPF (denoted I-Rm_UPF) I-Rm_UPF.

Step 10a: rl_SMF establishes an N4 session context for Rm PDU session with I-Rm_UPF.

Step 10b: the Rl_SMF retrieves the Rl SM context based on the Rl SM context ID, and further retrieves the Rl UPF anchor ID based on the Rl SM context, and the Rl_SMF establishes an N4 session context of the Rm PDU session with the Rl UPF anchor (Rl UPF corresponding to the Rl UPF anchor ID).

Step 11: the rl_smf initiates Rl PDU session Modification procedure.

Step 12: rl_smf continues with the subsequent Rm PDU session Establishment process.

In some embodiments, step 9, step 10a, step 11 are optional steps.

Example 3: rm_AMF initiates the SMF selection process, rm_AMF selects an intermediate SMF (denoted I-Rm_SMF).

Referring to fig. 16, the specific steps are as follows:

Step 0b: rm_UE starts path switching;

(1) The Rm_UE application layer triggers path switching;

(2) The Rm_UE AS layer indicates that the quality of the PC5 link is poor;

(3) A handover indication or command trigger is received for the relay network (e.g., rl_amf).

Step 1: rm_UE sends a first request message to Rl_UE;

Step 2: the Rl_UE sends a first request reply message to the Rm_UE.

Optionally, the third request reply message may include: rl_UPF Anchor ID.

In some embodiments, step 5 and step 6 are optional steps.

Step 7: the rl_amf sends a second request reply message to the rm_amf.

Step 8: rm_AMF selects an intermediate I-Rm_SMF

Step 9: rm_AMF sends PDU session context setup request message to Rm_SMF.

Step 10: rm_SMF selects the intermediate I-Rm_UPF.

Step 11: rm_SMF establishes an N4 session with the intermediate I-Rm_UPF.

Step 12: rm_SMF retrieves Rl SMF according to Rl_SMF ID and sends PDU session context establishment request message to Rl_SMF.

Optionally, the PDU session context setup request message may further comprise one or more of the following: (1) The Rl SM context ID, (2) rm_ue IP, further, the PDU session context setup request message may further include: rl UPF Anchor ID.

Step 13: rl_SMF retrieves Rl SM context based on Rl SM context ID, and further retrieves Rl UPF anchor ID based on Rl SM context, rl_SMF establishes N4 session context of Rm PDU session with Rl UPF anchor (Rl UPF corresponding to Rl UPF anchor ID)

Step 14: rl_SMF initiates Rl PDU session Modification procedure

In some embodiments, step 14 is an optional step.

Step 15: the rl_smf replies to the rm_smf with a PDU session context setup request.

Step 16: rm_smf continues with the subsequent Rm PDU session Establishment process.

Example 4: rm_AMF selects one (not Rl_SMF) SMF as Rm_SMF.

Referring to fig. 17, the specific steps are as follows:

Step 0b: rm_UE starts path switching;

(1) The Rm_UE application layer triggers path switching;

(2) The Rm_UE AS layer indicates that the quality of the PC5 link is poor;

Step 1: rm_UE sends a first request message to Rl_UE;

Step 2: the Rl_UE sends a first request reply message to the Rm_UE.

Step 5: the rl_amf sends a second request reply message to the rm_amf.

Step 6: rm_AMF selects one (not Rl_SMF) SMF as Rm_SMF.

Step 7: rm_AMF sends PDU session context setup request message to Rm_SMF.

Optionally, the PDU session context setup request message may include one or more of the following: (1) Rl_SMF ID, (2) Rm PDU session ID, (3) Rl SM context ID, (4) Rm_UE IP.

Step 8: rm_SMF retrieves Rl SMF according to Rl_SMF ID and sends relay PDU session context acquisition request message to Rl_SMF.

Optionally, the relay PDU session context acquisition request message may carry an Rl SM context ID, and further may further include Rm PDU session ID.

Step 9: the rl_smf sends a relay PDU session context acquisition request reply message to the rm_smf.

Optionally, the relay PDU session context acquisition request reply message may carry one or more of the following: (1) R1SM context and (2) Rl UPF anchor ID.

Step 10: rl_SMF selects an intermediate UPF (denoted as I-Rm_UPF).

Step 11a: rm_SMF establishes an N4 session with I-Rl_UPF.

Step 11b: the Rm_SMF selects a UPF corresponding to the Rl UPF anchor ID as a UPF anchor of Rm PDU session, and establishes an N4 session with the Rl UPF anchor.

Step 12: rm_SMF sends a relay PDU session change request to Rl_SMF.

Step 13: the rl_smf initiates a relay PDU session change procedure.

Step 14: rl_SMF sends a change reply message of the relay PDU session to Rm_SMF

Step 15: rm_SMF continues with subsequent Rm PDU session Establishment process

In some embodiments, step 10, step 11a, step 13 are optional steps.

Embodiment two: the remote terminal receives a switching indication or a switching command of the relay network or the relay terminal, and the switching indication or the switching command provides relevant information of the relay PDU session and/or relay network element information.

Example 1: rm_AMF selects SMF corresponding to Rl_SMF ID.

Referring to fig. 18, the specific steps are as follows:

step 0: a relay UE (hereinafter referred to as rl_ue) has established a dedicated relay PDU session (relay PDU session, hereinafter referred to as Rl PDU session) for a remote UE (hereinafter referred to as rm_ue), which session is identified with Rl PDU session ID.

Step 1a: rm_UE receives a handover command message from a relay AMF (hereinafter referred to as Rl_AMF).

Optionally, the handover command message may include one or more of:

(1) Relay UE 5G-GUTI (hereinafter referred to as Rl 5G-GUTI);

(2)Rl PDU session ID；

(3) Remote UE IP (hereinafter referred to as rm_ue IP).

Step 1b: rm_UE receives a handover command message from Rl_UE.

Optionally, the handover command message may include one or more of:

(1)Rl 5G-GUTI；

(2)Rl PDU session ID；

(3)Rm_UE IP。

step 2a: rm_UE sends a handover command reply message to Rl AMF.

Step 2b: rm_UE sends a handover command reply message to Rl_UE.

In some embodiments, steps 2a and 2b are optional steps.

Step 3: the rm_ue initiates a PDU session establishment procedure and transmits a PDU session establishment request message to an AMF (hereinafter referred to as rm_amf) served by the rm_ue.

Optionally, the PDU session establishment request message comprises one or more of the following: (1) Rm_UE establishes Rm PDU session identification (Rm PDU session ID) in a remote UE service network, (2) Rl 5G-GUTI and (3) Rl PDU session ID, and further, the PDU session establishment request message may further include: rl UPF Anchor ID.

Step 4: rm_AMF sends PDU session context setup request message to Rl_SMF.

Step 5: rl_SMF selects an intermediate I-Rm_UPF.

Step 6a: rl_SMF establishes an N4 session context for Rm PDU session with I-Rm_UPF.

Step 6b: the Rl_SMF retrieves the Rl SM context based on the Rl SM context ID, and further retrieves the Rl UPF anchor ID based on the Rl SM context, and the Rl_SMF establishes an N4 session context of the Rm PDU session with the Rl UPF anchor (Rl UPF corresponding to the Rl UPF anchor ID).

Step 7: the rl_smf initiates Rl PDU session Modification procedure.

Step 8: rl_smf continues with the subsequent Rm PDU session Establishment process.

In some embodiments, step 5, step 6a, step 7 are optional steps.

Example 2: rm_AMF selects SMF corresponding to Rl_SMF ID.

Referring to fig. 19, the specific steps are as follows:

Optionally, the handover command message may include one or more of:

(1) Relay UE 5G-GUTI (hereinafter referred to as Rl 5G-GUTI);

(2)Rl PDU session ID；

(3) Remote UE IP (hereinafter referred to as rm_ue IP).

Step 1b: rm_UE receives a handover command message from Rl_UE.

Optionally, the handover command message may include one or more of:

(1)Rl 5G-GUTI；

(2)Rl PDU session ID；

(3)Rm_UE IP。

step 2a: rm_UE sends a handover command reply message to Rl AMF.

Step 2b: rm_UE sends a handover command reply message to Rl_UE.

In some embodiments, steps 2a and 2b are optional steps.

Step 4: rm_AMF sends PDU session context setup request message to Rl_SMF.

Step 5: rl_SMF selects an intermediate I-Rm_UPF.

Step 7: the rl_smf initiates Rl PDU session Modification procedure.

In some embodiments, step 5, step 60a, step 7 are optional steps.

Example 3: rm_AMF initiates the SMF selection process, rm_AMF selects an intermediate I-Rm_SMF.

Referring to fig. 20, the specific steps are as follows:

Optionally, the handover command message may include one or more of:

(1) Relay UE 5G-GUTI (hereinafter referred to as Rl 5G-GUTI);

(2)Rl PDU session ID；

(3) Remote UE IP (hereinafter referred to as rm_ue IP).

Step 1b: rm_UE receives a handover command message from Rl_UE.

Optionally, the handover command message may include one or more of:

(1)Rl 5G-GUTI；

(2)Rl PDU session ID；

(3)Rm_UE IP。

step 2a: rm_UE sends a handover command reply message to Rl AMF.

Step 2b: rm_UE sends a handover command reply message to Rl_UE.

In some embodiments, steps 2a and 2b are optional steps.

Step 4: rm_AMF selects one Rm_SMF.

Step 5: rm_AMF sends PDU session context setup request message to Rm_SMF.

Step 6: rm_SMF selects the intermediate I-Rm_UPF.

Step 7: the I-rm_smf establishes an N4 session with the intermediate I-rm_upf.

Step 8: rm_SMF retrieves Rl SMF according to Rl_SMF ID and sends PDU session context establishment request message to Rl_SMF.

Step 9: rl_SMF retrieves Rl SM context based on Rl SM context ID, and further retrieves Rl UPF anchor ID based on Rl SM context, rl_SMF establishes N4 session context of Rm PDU session with Rl UPF anchor (Rl UPF corresponding to Rl UPF anchor ID)

Step 10: rl_SMF initiates Rl PDU session Modification procedure

In some embodiments, step 10 is an optional step.

Step 11: the rl_smf sends a PDU session context setup request reply message to the rm_smf.

Step 12: rm_smf continues with the subsequent Rm PDU session Establishment process.

Example 4: rm_AMF selects one (not Rl_SMF) SMF as Rm_SMF.

Referring to fig. 21, the specific steps are as follows:

Optionally, the handover command message may include one or more of:

(1) Relay UE 5G-GUTI (hereinafter referred to as Rl 5G-GUTI);

(2)Rl PDU session ID；

(3) Remote UE IP (hereinafter referred to as rm_ue IP).

Step 1b: rm_UE receives a handover command message from Rl_UE.

Optionally, the handover command message may include one or more of:

(1)Rl 5G-GUTI；

(2)Rl PDU session ID；

(3)Rm_UE IP。

step 2a: rm_UE sends a handover command reply message to Rl AMF.

Step 2b: rm_UE sends a handover command reply message to Rl_UE.

In some embodiments, steps 2a and 2b are optional steps.

Step 4: rm_AMF selects one (not Rl_SMF) SMF as the middle Rm_SMF.

Step 5: rm_AMF sends PDU session context setup request message to Rm_SMF.

Step 6: rm_SMF retrieves Rl SMF according to Rl_SMF ID and sends relay PDU session context acquisition request message to Rl_SMF.

Step 7: the rl_smf sends a relay PDU session context acquisition request reply message to the rm_smf.

Step 8: rl_SMF selects an intermediate I-Rm_UPF.

Step 9a: rm_SMF establishes an N4 session with I-Rl_UPF.

Step 9b: the Rm_SMF selects a UPF corresponding to the Rl UPF anchor ID as a UPF anchor of Rm PDU session, and establishes an N4 session with the Rl UPF anchor.

Step 10: rm_SMF sends a relay PDU session change request to Rl_SMF.

Step 11: the rl_smf initiates a relay PDU session change procedure.

Step 12: the rl_smf sends a change reply message of the relay PDU session to the rm_smf.

Step 13: rm_smf continues with the subsequent Rm PDU session Establishment process.

In some embodiments, step 8, step 9a, step 11 are optional steps.

The embodiment of the invention also provides a first terminal, and because the principle of solving the problem of the first terminal is similar to that of the switching method in the embodiment of the invention, the implementation of the first terminal can refer to the implementation of the method, and the repetition is not repeated.

Referring to fig. 22, an embodiment of the present invention further provides a first terminal 2200 including:

a first sending module 2201, configured to send, when the first terminal needs to switch from short-range direct communication interface communication to Uu interface communication, a request message for establishing a second PDU session to a service network of the first terminal;

In some embodiments, the first terminal 2200 further comprises:

the second sending module is used for sending a first request message, wherein the first request message is used for requesting to acquire the identifier of the second terminal and/or the identifier of the first PDU session;

And the first receiving module is used for receiving a first request reply message, and the first request reply message comprises the identification of the second terminal and/or the identification of the first PDU session.

In some embodiments, the identity of the second terminal is a fifth generation mobile communication technology of the second terminal-a globally unique temporary terminal identity.

In some embodiments, the first terminal 2200 further comprises: and the second receiving module is used for receiving a switching command from the service network of the second terminal or the second terminal, wherein the switching command indicates the path switching of the first terminal.

In some embodiments, the first terminal 2200 further comprises: and the third sending module is used for sending a switching command reply message to the service network of the second terminal or the second terminal.

In some embodiments, the handover command includes one or more of the following: the identity of the second terminal; an identification of the first PDU session; the IP address of the first terminal is the IP address allocated to the first terminal by the second terminal when the second terminal establishes connection with the first terminal.

In some embodiments, the second PDU session setup request message includes one or more of the following: the identity of the second terminal; an identification of the first PDU session; an identification of the second PDU session; the IP address of the first terminal.

The first terminal provided in the embodiment of the present invention may execute the embodiment shown in fig. 4, and its implementation principle and technical effects are similar, and this embodiment will not be described herein.

The embodiment of the invention also provides a second terminal, and because the principle of solving the problem of the second terminal is similar to that of the switching method in the embodiment of the invention, the implementation of the second terminal can be referred to the implementation of the method, and the repetition is not repeated.

Referring to fig. 23, an embodiment of the present invention also provides a second terminal, the second terminal 2300 including:

a third receiving module 2301, configured to receive a first request message from a first terminal, where the first request message is used to request to obtain an identifier of the second terminal and/or an identifier of a first PDU session;

a fourth sending module 2302, configured to send a first request reply message to the first terminal, where the first request reply message includes an identifier of the second terminal and/or an identifier of the first PDU session, and when the first PDU session establishes relay communication with the second terminal for the first terminal, the second terminal establishes relay PDU session for the first terminal;

or,

a fifth sending module 2303, configured to send a handover command to a first terminal, where the handover command indicates that a path of the first terminal is switched.

In some embodiments, second terminal 2300 further comprises: and the fourth receiving module is used for receiving a switching command reply message from the first terminal.

The second terminal provided in the embodiment of the present invention may execute the embodiment shown in fig. 5, and its implementation principle and technical effects are similar, and this embodiment will not be described herein.

The embodiment of the invention also provides a first network function, and the principle of solving the problem of the first network function is similar to that of the switching method in the embodiment of the invention, so that the implementation of the first network function can be referred to the implementation of the method, and the repeated parts are not described again.

Referring to fig. 24, an embodiment of the present invention further provides a first network function 2400 including:

a fifth receiving module 2401, configured to receive a request message for establishing a second PDU session sent by the first terminal;

In some embodiments, the first network function 2400 further includes: a sixth sending module, configured to send a second request message to a second network function, where the second request message is used to request the second network function to provide information related to the first PDU session.

In some embodiments, the first network function 2400 further includes: a sixth receiving module, configured to receive a second request reply message from the second network function, where the second request reply message includes: information related to the first PDU session.

In some embodiments, the information related to the first PDU session includes one or more of: an identification of a fourth network function, the fourth network function being configured to establish the first PDU session; a context identification of the first PDU session; an identification of a fifth network function, the fifth network function being an anchor point for the first PDU session.

In some embodiments, the second request message includes one or more of the following: an identification of the second terminal, an identification of the first PDU session.

In some embodiments, the first network function 2400 further includes: and the first selecting module is used for selecting a third network function according to the identification of the fourth network function, and the third network function is used for establishing the second PDU session.

In some embodiments, the first network function 2400 further includes: a second selection module for selecting a third network function based on a selection policy of a session management function, the third network function being for establishing the second PDU session.

In some embodiments, the first network function 2400 further includes: and a seventh sending module, configured to send a context establishment request message of the second PDU session to the third network function.

In some embodiments, the context setup request message of the second PDU session includes one or more of: the second PDU session identifier; the first PDU session identifier; the IP address of the first terminal is the IP address allocated to the first terminal by the second terminal when the second terminal establishes connection with the first terminal; identification of a fourth network function; identification of the fifth network function.

The first network function provided in the embodiment of the present invention may execute the embodiment shown in fig. 6, and its implementation principle and technical effects are similar, and this embodiment will not be described herein.

The embodiment of the invention also provides a second network function, and because the principle of solving the problem of the second network function is similar to that of the switching method in the embodiment of the invention, the implementation of the second network function can be referred to the implementation of the method, and the repeated parts are not described again.

Referring to fig. 25, an embodiment of the present invention further provides a second network function 2500 including:

a seventh receiving module 2501, configured to receive a second request message, and determine information related to a first PDU session according to the second request message, where the first PDU session is a relay PDU session established by a first terminal and a second terminal when the second terminal establishes relay communication with the first terminal;

an eighth transmitting module 2502, configured to transmit a second request reply message, where the second request reply message includes: the information related to the first PDU session;

or,

a ninth sending module 2503 is configured to send a handover command to the first terminal, where the handover command indicates that the path of the first terminal is switched.

In some embodiments, the second network function 2500 further comprises: and the eighth receiving module is used for receiving a switching command reply message from the first terminal.

In some embodiments, the second network function 2500 further comprises: a tenth sending module, configured to send a third request message to a fourth network function, where the third request message is used to request the fourth network function to provide an identifier of a fifth network function.

In some embodiments, the second network function 2500 further comprises: a ninth receiving module, configured to receive a third request reply message, where the third request reply message includes an identifier of the fifth network function.

In some embodiments, the third request message includes one or more of the following: a context identification of the first PDU session; and the identification of the first PDU session.

The second network function provided in the embodiment of the present invention may execute the embodiment shown in fig. 7, and its implementation principle and technical effects are similar, and this embodiment will not be described herein.

The embodiment of the invention also provides a third network function, and because the principle of solving the problem of the third network function is similar to that of the switching method in the embodiment of the invention, the implementation of the third network function can be referred to the implementation of the method, and the repeated parts are not described again.

Referring to fig. 26, an embodiment of the present invention also provides a third network function 2600 including:

a tenth receiving module 2601, configured to receive a context setup request message of the second PDU session from the first network function;

In some implementations, third network function 2600 further includes:

a first establishing module, configured to establish an N4 session context of a second PDU session with a fifth network function, where the fifth network function is an anchor point of the first PDU session;

an eleventh sending module, configured to send a change request message of the first PDU session to a fourth network function, where the fourth network function is configured to establish the first PDU session;

an eleventh receiving module is configured to receive a change request reply message of the first PDU session from the fourth network function.

In some implementations, third network function 2600 further includes: and a third selecting module, configured to initiate a user plane function selecting process, and select a sixth network function, where the sixth network function is an intermediate UPF of the second PDU session.

In some implementations, third network function 2600 further includes: a second establishing module, configured to establish an N4 session context of the second PDU session with the sixth network function.

In some implementations, third network function 2600 further includes:

and a fourth selecting module, configured to initiate a user plane function selecting process, and select a sixth network function, where the sixth network function is an intermediate UPF of the second PDU session.

A third establishing module, configured to establish an N4 session context of the second PDU session with the sixth network function;

a twelfth sending module, configured to send a context establishment request message of the second PDU session to a fourth network function, where the fourth network function is configured to establish the first PDU session;

a twelfth receiving module, configured to receive a context setup reply message of the second PDU session from the fourth network function.

In some implementations, third network function 2600 further includes:

a thirteenth sending module, configured to send a context acquisition request message of the first PDU session to a fourth network function, where the fourth network function is configured to establish the first PDU session;

a thirteenth receiving module, configured to receive a context acquisition request reply message of the first PDU session from the fourth network function;

a fourth establishing module, configured to establish an N4 session context of the second PDU session with the fifth network function, where the fifth network function is an anchor point of the first PDU session;

a fourteenth transmitting module, configured to transmit a change request message of the first PDU session to the fourth network function;

A fourteenth receiving module is configured to receive a change request reply message of the first PDU session from the fourth network function.

In some implementations, third network function 2600 further includes: and a fifth selecting module, configured to initiate a user plane function selecting process, and select a sixth network function, where the sixth network function is an intermediate UPF of the second PDU session.

In some implementations, third network function 2600 further includes: a fifth establishing module, configured to establish an N4 session context of the second PDU session with the sixth network function.

In some embodiments, the change request message of the first PDU session includes one or more of the following:

a context identification of the first PDU session;

the IP address of the first terminal is the IP address allocated to the first terminal by the second terminal when the second terminal establishes connection with the first terminal;

and an identification of the fifth network function.

In some embodiments, the context setup request message of the second PDU session includes one or more of:

the second PDU session identifier;

the first PDU session identifier;

The IP address of the first terminal is the IP address allocated to the first terminal by the second terminal when the second terminal establishes PC5 connection with the first terminal;

identification of a fourth network function;

identification of the fifth network function.

The third network function provided in the embodiment of the present invention may execute the embodiment shown in fig. 8, and its implementation principle and technical effects are similar, and this embodiment will not be described herein.

The embodiment of the invention also provides a fourth network function, and because the principle of solving the problem of the fourth network function is similar to that of the switching method in the embodiment of the invention, the implementation of the fourth network function can be referred to the implementation of the method, and the repeated parts are not described again.

Referring to fig. 27, an embodiment of the present invention further provides a fourth network function, the fourth network function 2700 includes:

a fifteenth receiving module 2701 for receiving a context setup request message of the second PDU session from the first network function;

In some embodiments, fourth network function 2700 further includes:

a sixteenth receiving module, configured to receive a third request message from a second network function, where the third request message is configured to request the fourth network function to provide an identifier of a fifth network function, and the fifth network function is an anchor point of the first PDU session;

a fifteenth sending module, configured to send a third request reply message to the second network function, where the third request reply message includes an identifier of the fifth network function.

In some embodiments, the third request message includes one or more of the following:

a context identification of the first PDU session;

and the identification of the first PDU session.

In some embodiments, fourth network function 2700 further includes: a sixth establishing module, configured to use the fifth network function as an anchor point of the second PDU session, and establish an N4 session context of the second PDU session with the fifth network function.

In some embodiments, fourth network function 2700 further includes: a sixth selecting module, configured to initiate a user plane function selecting process, and select a sixth network function, where the sixth network function is an intermediate UPF of the second PDU session.

In some embodiments, fourth network function 2700 further includes: a seventh establishing module, configured to establish an N4 session context of the second PDU session with the sixth network function.

In some embodiments, fourth network function 2700 further includes: a first initiation module for initiating a change procedure of the first PDU session after receiving a context setup request message of the second PDU session from the first network function.

The fourth network function provided in the embodiment of the present invention may execute the embodiment shown in fig. 9, and its implementation principle and technical effects are similar, and this embodiment will not be described herein.

Referring to fig. 28, an embodiment of the present invention further provides a fourth network function 2800 including:

a seventeenth receiving module 2801 for receiving a change request message of the first PDU session from the third network function;

a sixteenth sending module 2802 configured to send a change request reply message of the first PDU session to the third network function;

In some implementations, the fourth network function 2800 further includes: and the second initiating module is used for initiating a change process of the first PDU session after receiving a change request message of the first PDU session from the third network function.

In some implementations, the fourth network function 2800 further includes:

an eighteenth receiving module, configured to receive a third request message from a second network function, where the third request message is configured to request the fourth network function to provide an identifier of a fifth network function, and the fifth network function is an anchor point of the first PDU session;

a seventeenth sending module, configured to send a third request reply message to the second network function, where the third request reply message includes an identifier of the fifth network function.

a context identification of the first PDU session;

and the identification of the first PDU session.

Referring to fig. 29, an embodiment of the present invention further provides a fourth network function 2900 including:

a nineteenth receiving module 2901 that receives a context setup request message for the second PDU session from the third network function;

an eighth establishing module 2902, configured to use the fifth network function as an anchor point of the second PDU session, and establish an N4 session context of the second PDU session with the fifth network function;

an eighteenth sending module 2903 configured to send a context setup request reply message of the second PDU session to the third network function;

In some implementations, the fourth network function 2900 further includes:

A twentieth receiving module, configured to receive a third request message from a second network function, where the third request message is configured to request the fourth network function to provide an identifier of a fifth network function, where the fifth network function is an anchor point of the first PDU session;

a nineteenth sending module, configured to send a third request reply message to the second network function, where the third request reply message includes an identifier of the fifth network function.

a context identification of the first PDU session;

and the identification of the first PDU session.

In some implementations, the fourth network function 2900 further includes: a third initiation module, configured to initiate a modification procedure of the first PDU session after establishing an N4 session context of the second PDU session with a fifth network function.

Referring to fig. 30, an embodiment of the present invention further provides a fourth network function 3000 including:

a twenty-first receiving module 3001, configured to receive a context acquisition request message of a second PDU session from a third network function, where the third network function is configured to establish the second PDU session;

a twentieth transmitting module 3002, configured to send a context acquisition reply message of the second PDU session to the third network function;

a twenty-second receiving module 3003, configured to receive a change request message of the first PDU session from the third network function;

a twenty-first transmitting module 3004, configured to transmit a change request reply message of the first PDU session to the third network function;

In some embodiments, fourth network function 3000 further comprises: a fourth initiation module, configured to initiate a modification procedure of the first PDU session after receiving a modification request message of the first PDU session from the third network function.

As shown in fig. 31, the terminal 3100 shown in fig. 31 includes: at least one processor 3101, memory 3102, at least one network interface 3104, and a user interface 3103. The various components in terminal 3100 are coupled together by a bus system 3105. It is appreciated that the bus system 3105 is employed to facilitate connected communications between these components. The bus system 3105 includes a power bus, a control bus, and a status signal bus in addition to the data bus. For clarity of illustration, however, the various buses are labeled as bus system 3105 in fig. 31.

The user interface 3103 may include, among other things, a display, a keyboard, or a pointing device (e.g., a mouse, trackball, touch pad, or touch screen, etc.).

It will be appreciated that the memory 3102 in embodiments of the invention can be either volatile memory or nonvolatile memory, or can include both volatile and nonvolatile memory. The nonvolatile Memory may be a Read-Only Memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an Electrically Erasable EPROM (EEPROM), or a flash Memory. The volatile memory may be random access memory (Random Access Memory, RAM) which acts as an external cache. By way of example, and not limitation, many forms of RAM are available, such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double Data rate SDRAM (Double Data rate SDRAM), enhanced SDRAM (ESDRAM), synchronous DRAM (SLDRAM), and Direct RAM (DRRAM). The memory 3102 of the systems and methods described in embodiments of the invention is intended to comprise, without being limited to, these and any other suitable types of memory.

In some implementations, the memory 3102 holds the following elements, executable modules or data structures, or a subset thereof, or an extended set thereof: an operating system 31021 and application programs 31022.

The operating system 31021 includes various system programs, such as a framework layer, a core library layer, a driver layer, and the like, for implementing various basic services and processing hardware-based tasks. The application programs 31022 include various application programs such as a Media Player (Media Player), a Browser (Browser), and the like for realizing various application services. The program for implementing the method of the embodiment of the present invention may be contained in the application program 31022.

In one embodiment of the present invention, the steps described in the terminal-side method above are implemented when executed by calling a program or an instruction stored in the memory 3102, specifically, a program or an instruction stored in the application program 31022.

The terminal provided by the embodiment of the present invention may execute the above method embodiment, and its implementation principle and technical effects are similar, and this embodiment will not be described herein.

Referring to fig. 32, fig. 32 is a block diagram of a network device to which an embodiment of the present invention is applied, and as shown in fig. 32, a network device 3200 includes: a processor 3201, a transceiver 3202, a memory 3203 and a bus interface, wherein the processor 3201 may be responsible for managing the bus architecture and general processing. The memory 3203 may store data used by the processor 3201 in performing operations.

In one embodiment of the present invention, the network device 3200 further comprises: computer programs stored on the memory 3203 and executable on the processor 3201, which when executed by the processor 3201 implement the steps in the method shown on the network side above.

In fig. 32, a bus architecture may include any number of interconnecting buses and bridges, with various circuits of one or more processors, typically represented by processor 3201, and memory, typically memory 3203, being linked together. The bus architecture may also link together various other circuits such as peripheral devices, voltage regulators, power management circuits, etc., which are well known in the art and, therefore, will not be described further herein. The bus interface provides an interface. The transceiver 3202 may be a number of elements, i.e. include a transmitter and a receiver, providing a means for communicating with various other apparatus over a transmission medium.

The network device provided in the embodiment of the present invention may execute the above method embodiment, and its implementation principle and technical effects are similar, and this embodiment will not be described herein.

The steps of a method or algorithm described in connection with the present disclosure may be embodied in hardware, or may be embodied in software instructions executed by a processor. The software instructions may be comprised of corresponding software modules that may be stored in RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disk, a removable disk, a read-only optical disk, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. In addition, the ASIC may be located in a core network interface device. The processor and the storage medium may reside as discrete components in a core network interface device.

Those skilled in the art will appreciate that in one or more of the examples described above, the functions described in the present invention may be implemented in hardware, software, firmware, or any combination thereof. When implemented in software, these functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer.

The foregoing embodiments have been provided for the purpose of illustrating the general principles of the present invention in further detail, and are not to be construed as limiting the scope of the invention, but are merely intended to cover any modifications, equivalents, improvements, etc. based on the teachings of the invention.

It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, embodiments of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, embodiments of the invention may take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

Embodiments of the present invention are described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the embodiments of the present invention fall within the scope of the claims and the equivalents thereof, the present invention is also intended to include such modifications and variations.

Claims

1. The switching method is applied to a first terminal and is characterized by comprising the following steps:

2. The method according to claim 1, wherein before said sending a setup request message for a second PDU session to the serving network of the first terminal, the method further comprises:

sending a first request message, wherein the first request message is used for requesting to acquire the identifier of the second terminal and/or the identifier of the first PDU session;

a first request reply message is received, the first request reply message comprising an identification of the second terminal and/or an identification of the first PDU session.

3. Method according to claim 2, characterized in that the identity of the second terminal is a fifth generation mobile communication technology of the second terminal-globally unique temporary terminal identity.

4. The method according to claim 1, wherein before said sending a setup request message for a second PDU session to the serving network of the first terminal, the method further comprises:

a handover command is received from the serving network of the second terminal or the second terminal, the handover command indicating the first terminal path handover.

5. The method according to claim 4, wherein the method further comprises:

and sending a switching command reply message to the service network of the second terminal or the second terminal.

6. The method of claim 4, wherein the handover command comprises one or more of:

the identity of the second terminal;

an identification of the first PDU session;

the IP address of the first terminal is the IP address allocated to the first terminal by the second terminal when the second terminal establishes connection with the first terminal.

7. The method of claim 1, wherein the second PDU session setup request message comprises one or more of:

the identity of the second terminal;

an identification of the first PDU session;

an identification of the second PDU session;

the IP address of the first terminal.

8. The switching method applied to the second terminal is characterized by comprising the following steps:

transmitting a switching command of switching the first terminal from the short-range direct communication interface communication to the Uu interface communication to the first terminal so that the first terminal transmits a request message for establishing a second PDU session to a service network of the first terminal;

the switching command indicates the first terminal path to switch, and the switching command comprises an identifier of a first PDU session;

9. The method of claim 8, wherein the handover command further comprises one or more of:

the identity of the second terminal;

10. The method of claim 8, wherein the method further comprises:

and receiving a switching command reply message from the first terminal.

11. A handover method applied to a first network function, comprising:

receiving a second PDU session establishment request message sent by a first terminal, wherein the second PDU session establishment request message is sent when the first terminal is switched from short-range direct communication interface communication to Uu interface communication;

12. The method of claim 11, wherein the method further comprises:

And sending a second request message to a second network function, wherein the second request message is used for requesting the second network function to provide information related to the first PDU session.

13. The method according to claim 12, wherein the method further comprises:

receiving a second request reply message from the second network function, the second request reply message comprising: information related to the first PDU session.

14. The method according to claim 12 or 13, wherein the information related to the first PDU session comprises one or more of:

an identification of a fourth network function, the fourth network function being configured to establish the first PDU session;

a context identification of the first PDU session;

an identification of a fifth network function, the fifth network function being an anchor point for the first PDU session.

15. The method of claim 12, wherein the second request message comprises one or more of: an identification of the second terminal, an identification of the first PDU session.

16. The method of claim 13, wherein the second request reply message comprises: identification of a fourth network function, the method further comprising:

And selecting a third network function according to the identification of the fourth network function, wherein the third network function is used for establishing the second PDU session.

17. The method of claim 11, wherein the method further comprises:

a third network function is selected based on a selection policy of a session management function, the third network function being configured to establish the second PDU session.

18. The method according to claim 16 or 17, characterized in that the method further comprises:

and sending a request message for establishing the second PDU session to the third network function.

19. The method of claim 18, wherein the second PDU session setup request message comprises one or more of:

the second PDU session identifier;

the first PDU session identifier;

identification of a fourth network function;

identification of the fifth network function.

20. A handover method applied to a second network function, comprising:

transmitting a switching command of switching the first terminal from short-range direct communication interface communication to Uu interface communication to the first terminal so that the first terminal transmits a second PDU session establishment request message to a service network of the first terminal, wherein the switching command indicates path switching of the first terminal, and the switching command comprises an identification of the first PDU session;

The anchor point of the second PDU session is a user plane function anchor point corresponding to a first PDU session, and when the first PDU session is a relay communication established between a first terminal and a second terminal, the second terminal is a relay PDU session established by the first terminal.

21. The method of claim 20, wherein the method further comprises:

and receiving a switching command reply message from the first terminal.

22. The method of claim 20, wherein the handover command further comprises one or more of:

the identity of the second terminal;

23. The method of claim 20, wherein the information related to the first PDU session comprises one or more of:

a context identification of the first PDU session;

24. The method of claim 20, wherein the method further comprises:

and sending a third request message to a fourth network function, wherein the third request message is used for requesting the fourth network function to provide the identifier of a fifth network function.

25. The method of claim 24, wherein the method further comprises:

a third request reply message is received, the third request reply message including an identification of the fifth network function.

26. The method of claim 24, wherein the third request message comprises one or more of:

a context identification of the first PDU session;

and the identification of the first PDU session.

27. A handover method applied to a third network function, comprising:

receiving a second PDU session establishment request message from a first network function, wherein the second PDU session establishment request message is sent when the first terminal is switched from short-range direct communication interface communication to Uu interface communication;

28. The method of claim 27, wherein after receiving the setup request message for the second PDU session from the first network function, the method further comprises:

a fifth network function is used as an anchor point of a second PDU session, and an N4 session context of the second PDU session is established with the fifth network function, wherein the fifth network function is the anchor point of the first PDU session;

transmitting a change request message of the first PDU session to a fourth network function, wherein the fourth network function is used for establishing the first PDU session;

29. The method of claim 27, wherein after receiving the setup request message for the second PDU session from the first network function, the method further comprises:

sending an establishment request message of the second PDU session to a fourth network function;

30. The method of claim 27, wherein after receiving the setup request message for the second PDU session from the first network function, the method further comprises:

Sending a context acquisition request message of the first PDU session to a fourth network function;

establishing an N4 session context for the second PDU session with a fifth network function;

31. The method of claim 28 or 30, wherein the change request message of the first PDU session comprises one or more of:

a context identification of the first PDU session;

and an identification of the fifth network function.

32. The method of claim 27, 28, 29 or 30, wherein the second PDU session setup request message comprises one or more of:

the second PDU session identifier;

the first PDU session identifier;

the IP address of the first terminal is the IP address allocated to the first terminal by the second terminal when the second terminal establishes short-distance direct communication interface connection with the first terminal;

Identification of a fourth network function;

identification of the fifth network function.

33. A handover method applied to a fourth network function, comprising:

34. The method of claim 33, wherein prior to receiving the second PDU session establishment request message from the first network function, the method further comprises:

35. The method of claim 34, wherein the third request message comprises one or more of:

a context identification of the first PDU session;

and the identification of the first PDU session.

36. The method of claim 33, wherein after receiving the setup request message for the second PDU session from the first network function, the method further comprises:

an N4 session context for the second PDU session is established with a fifth network function.

37. The method of claim 33, wherein after receiving the setup request message for the second PDU session from the first network function, the method further comprises:

initiating a change procedure for the first PDU session.

38. A handover method applied to a fourth network function, comprising:

receiving a second PDU session establishment request message from a third network function, wherein the second PDU session establishment request message is sent when the first terminal is switched from short-range direct communication interface communication to Uu interface communication;

establishing an N4 session context of the second PDU session with a fifth network function by taking the fifth network function as an anchor point of the second PDU session;

39. The method of claim 38, wherein prior to receiving the second PDU session set up request message from the third network function, the method further comprises:

40. The method of claim 39, wherein the third request message includes one or more of:

a context identification of the first PDU session;

and the identification of the first PDU session.

41. The method of claim 38, wherein after establishing the N4 session context for the second PDU session with a fifth network function, the method further comprises:

Initiating a change procedure for the first PDU session.

42. A first terminal, comprising:

43. A second terminal, comprising:

a fifth sending module, configured to send a handover command for the first terminal to switch from short-range direct communication interface communication to Uu interface communication to the first terminal, so that the first terminal sends an establishment request message of a second PDU session to a service network of the first terminal, where the handover command indicates path handover of the first terminal, and the handover command includes an identifier of the first PDU session;

44. A first network function entity, comprising:

a fifth receiving module, configured to receive a request message for establishing a second PDU session sent by the first terminal; the establishment request message of the second PDU session is sent when the first terminal is switched from short-range direct communication interface communication to Uu interface communication;

45. A second network function entity, comprising:

a ninth sending module, configured to send a handover command for the first terminal to switch from short-range direct communication interface communication to Uu interface communication to the first terminal, so that the first terminal sends an establishment request message of a second PDU session to a service network of the first terminal, where the handover command indicates path handover of the first terminal, and the handover command includes an identifier of the first PDU session;

46. A third network function entity, comprising:

a tenth receiving module, configured to receive, from a first network function, a second PDU session establishment request message, where the second PDU session establishment request message is sent when the first terminal switches from short-range direct communication interface communication to Uu interface communication;

the anchor point of the second PDU session is a user plane function anchor point corresponding to a first PDU session, when the first PDU session is a relay communication established between a first terminal and a second terminal, the second terminal is a relay PDU session established by the first terminal, and the third network function is used for establishing the second PDU session.

47. A fourth network function entity, comprising:

a fifteenth receiving module, configured to receive, from a first network function, a second PDU session establishment request message, where the second PDU session establishment request message is sent when the first terminal switches from short-range direct communication interface communication to Uu interface communication;

48. A fourth network function entity, comprising:

a nineteenth receiving module, configured to receive, from a third network function, a second PDU session establishment request message, where the second PDU session establishment request message is sent when the first terminal switches from short-range direct communication interface communication to Uu interface communication;

49. A terminal, comprising: a processor, a memory and a program stored on the memory and executable on the processor, which when executed by the processor, implements the steps of the handover method according to any one of claims 1 to 10.

50. A network device, comprising: a processor, a memory and a program stored on the memory and executable on the processor, which when executed by the processor, performs the steps of the handover method according to any one of claims 11 to 41.

51. A computer readable storage medium, characterized in that the computer readable storage medium has stored thereon a computer program which, when executed by a processor, implements the steps of the handover method according to any of claims 1 to 41.