WO2024031349A1

WO2024031349A1 - Measurement for non-terrestrial network and terrestrial network mobility

Info

Publication number: WO2024031349A1
Application number: PCT/CN2022/111215
Authority: WO
Inventors: Fangli Xu; Yuqin Chen; Haijing Hu
Original assignee: Apple Inc.
Priority date: 2022-08-09
Filing date: 2022-08-09
Publication date: 2024-02-15

Abstract

Example embodiments of the present disclosure relate to a UE and a BS for a solution of measurement for non-terrestrial network and terrestrial network mobility. A UE being located in a non-terrestrial network cell receives a measurement configuration comprising a measurement condition; and if the measurement condition is met, the UE performs a measurement on a terrestrial network cell associated with the measurement condition, without performing a measurement on a further terrestrial network cell unassociated with the measurement condition. As such, there is no need for the UE to perform the measurement on all neighboring cells, thus the power consumption may be reduced.

Description

MEASUREMENT FOR NON-TERRESTRIAL NETWORK AND TERRESTRIAL NETWORK MOBILITY

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to the field of telecommunication and in particular, to a user equipment (UE) and a base station (BS) for a solution of measurement for non-terrestrial network and terrestrial network mobility.

BACKGROUND

A non-terrestrial network (NTN) refers to a network or a segment of network which uses an airborne or a space borne vehicle for transmission. The NTN may provide an NTN cell which covers a wider range than a terrestrial network (TN) cell provided by a TN. For a UE, when it is located within a serving cell, the measurement on the non-serving cells is needed for mobility purpose. The measurement may be performed on all non-serving cells, but the current solution is power consuming and is not efficient.

SUMMARY

In general, example embodiments of the present disclosure provide a solution for measurement for non-terrestrial network and terrestrial network mobility.

In a first aspect, there is provided a baseband processor of a UE configured to perform operations comprising: receiving, using a transceiver of the UE and from a BS, a measurement configuration comprising a measurement condition, the UE being located in a non-terrestrial network cell; and in accordance with a determination that the measurement condition is met, perform a measurement on a terrestrial network cell associated with the measurement condition, without performing a measurement on a further terrestrial network cell unassociated with the measurement condition.

In a second aspect, there is provided a processor of a BS configured to perform operations comprising: determining, for a UE being located in a non-terrestrial network cell, a measurement configuration comprising a measurement condition, the measurement condition when met causing the UE to perform a measurement on a terrestrial network cell associated with the measurement condition without performing a measurement on a further terrestrial network cell unassociated with the measurement condition; and transmitting, using a transceiver of the BS, the measurement configuration to the UE.

In a third aspect, there is provided a UE. The UE comprises: a transceiver configured to communicate with a network; and a processor communicatively coupled to the transceiver and configured to perform operations comprising: receiving, using the transceiver and from a BS, a measurement configuration comprising a measurement condition, the UE being located in a non-terrestrial network cell; and in accordance with a determination that the measurement condition is met, performing a measurement on a terrestrial network cell associated with the measurement condition, without performing a measurement on a further terrestrial network cell unassociated with the measurement condition.

In a fourth aspect, there is provided a BS. The BS comprises: a transceiver configured to communicate with a network; and a processor communicatively coupled to the transceiver and configured to perform operations comprising: determining, for a UE being located in a non-terrestrial network cell, a measurement configuration comprising a measurement condition, the measurement condition when met causing the UE to perform a measurement on a terrestrial network cell associated with the measurement condition without performing a measurement on a further terrestrial network cell unassociated with the measurement condition; and transmitting, using the transceiver, the measurement configuration to the UE.

It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Through the more detailed description of some embodiments of the present disclosure in the accompanying drawings, the above and other objects, features and advantages of the present disclosure will become more apparent, wherein:

FIG. 1 illustrates an example network environment in which some example embodiments of the present disclosure may be implemented;

FIG. 2 illustrates an example of a process flow in accordance with some example embodiments of the present disclosure;

FIG. 3 illustrates another example network environment in which some example embodiments of the present disclosure may be implemented;

FIG. 4 illustrates an example process of measurement in accordance with some example embodiments of the present disclosure;

FIG. 5 illustrates an example process of handover in accordance with some example embodiments of the present disclosure;

FIG. 6 illustrates a flowchart of a method implemented at a UE in accordance with some example embodiments of the present disclosure;

FIG. 7 illustrates a flowchart of a method implemented at a BS in accordance with some example embodiments of the present disclosure; and

FIG. 8 illustrates a simplified block diagram of a device that is suitable for implementing some example embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar elements.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. For example, as used herein, the singular forms “a” , “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” , when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof. Moreover, when a particular feature, structure, or characteristic is described in connection with some embodiments, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It is also to be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

As mentioned above, an NTN may use an airborne vehicle or a space borne vehicle for transmission. The airborne vehicle may include a satellite, such as a low earth orbit (LEO) satellite, a medium earth orbit (MEO) satellite, a geosynchronous orbit (GEO) satellite, a highly eccentric orbit (HEO) satellite or another type of satellite. In some specific cases, the satellite may also, or alternatively pertain to one or more satellite systems or architectures, such as a global navigation satellite system (GNSS) , global positioning system (GPS) , global navigation satellite system (GLONASS) , BeiDou navigation satellite system (BDS) , etc. The space borne vehicle may include high altitude platforms (HAPS) .

The NTN may be used in multiple different scenarios, such as maritime, airplane connectivity or railway, so as to address mobile broadband needs and public safety needs in unserved or underserved areas. In a new radio (NR) system, the NTN, especially LEO or GEO, may have implicit compatibility to support both HAPS and air-to-ground (ATG) scenarios. It is agreed in release 17 (R17) that the NTN may focus on frequency division duplexing (FDD) while time division duplexing (TDD) may be applied for relevant scenarios, such as HAPS or ATG. In some events, the NTN may provide an earth fixed tracking area, and a user equipment (UE) in the NTN may have a GNSS capability.

In some events, the transmission in the NTN may be a transparent payload for the satellite. The NTN may be available for handheld devices in frequency range 1 (FR1) , such as with a power class 3, and for very small aperture terminal (VSAT) devices with an external antenna at least in frequency range 2 (FR2) . The NTN may provide an NTN cell with a wider coverage than a TN cell. Specifically, in NTN, the coverage of a cell or a beam is typically much larger than a cell in TN. For example, the coverage of an NTN cell may across multiple countries in some cases.

In R17, the mobility of the UE in a connected mode has been studied. In some events, legacy handover (HO) mechanisms may be supported with some restrictions: the UE is not required to connect to both an NTN cell and a TN cell simultaneously during a handover, and a dual active protocol stack (DAPS) is not supported. In R17, additional conditional handover (CHO) conditions are introduced for NTN specific CHO due to the NTN radio characteristics, i.e., the variation in signal strength or signal quality between cell-center and cell-edge is not so pronounced. The NTN specific CHO conditions may include a condEventT1 and condEventD1 for example, and condEventT1 and condEventD1 are always configured together with one of the measurement-based trigger conditions (CHO events A3/A4/A5) . In some cases, the condEventD1 may be configured as a normal measurement event for measurement report.

In some events, for a candidate cell with condEventT1, the CHO recovery may not be executed if timer T2 has not expired. In some events, for a candidate cell with condEventD1, the CHO recovery can be excluded without checking condEventD1. Some of the conditions are listed in Table 1 below for reference.

Table 1

In R18, the mobility and service continuity enhancements are further studied. For example, some agreements are shown in the text box below.

For a specific UE, when it is located within a serving cell, there may be multiple neighboring cells. In some cases, a measurement on non-serving cells is needed for mobility purpose. However, the current measurement is low efficient and power consuming, thus needs to be further studied.

Example embodiments of the present disclosure provide a solution for measurement for non-terrestrial network and terrestrial network mobility. Specifically, when a measurement condition is met, the UE may perform a measurement on a terrestrial network cell which is associated with the measurement condition. For example, the terrestrial network cell may be one of multiple neighboring cells, as such, the UE does not need to perform measurements on all neighboring cells. Thus, the power consumption at the UE may be reduced and the efficiency may be improved. Principles and some example embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

FIG. 1 illustrates an example network environment 100 in which some example embodiments of the present disclosure may be implemented. The network environment 100 may include a UE 110 and a satellite 130. As shown in FIG. 1, the network environment 100 may include an NTN comprising the satellite 130 in communication with the UE 110. The device 120 shown in FIG. 1 may be a gateway (GW) device or a base station.

In some embodiments, the device 120 may be a BS 120 (such as a gNB) . The satellite 130 may communicate with the UE 110 via a service link or a wireless interface, and the satellite 130 may communicate with the BS 120 via a feeder link or a wireless interface. In some embodiments, the satellite 130 may operate as a passive or transparent network relay node between the UE 110 and the BS 120. As shown in FIG. 1, the BS 120 may further communicate with a 5G core network (5G-CN) 140, for example via a gateway device. In some other embodiments, the device 120 may be a gateway device 120. The satellite 130 may operate as a further BS, such as another gNB. In some embodiments, the satellite 130 may communicate with the gateway device 120 associated with the 5G-CN 140.

Communications in the network environment 100 may be implemented according to any proper communication protocol (s) , comprising, but not limited to, cellular communication protocols of the first generation (1G) , the second generation (2G) , the third generation (3G) , the fourth generation (4G) , the fifth generation (5G) and the sixth generation (6G) and the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and/or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA) , Frequency Division Multiple Access (FDMA) , Time Division Multiple Access (TDMA) , Frequency Division Duplex (FDD) , Time Division Duplex (TDD) , Multiple-Input Multiple-Output (MIMO) , Orthogonal Frequency Division Multiple (OFDM) , Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and/or any other technologies currently known or to be developed in the future.

It is to be understood that the numbers of devices (i.e., the UE 110, the device (such as GW/gNB) 120 and the satellite 130) and their connection relationships and types shown in FIG. 1 are only for the purpose of illustration without suggesting any limitation. The environment 100 may include any suitable numbers of devices adapted for implementing embodiments of the present disclosure.

It is to be understood that the network environment 100 shown in FIG. 1 is only for the purpose of illustration without suggesting any limitation as to the scope of the disclosure. For example, while FIG. 1 depicts the UE 110 as a mobile phone, the UE 110 may be any type of user equipment.

FIG. 2 illustrates an example of a process flow 200 in accordance with some example embodiments of the present disclosure. The process flow 200 involves a UE 201 and a BS 202. With reference to FIG. 1, the UE 201 may be the UE 110, the BS 202 may be the BS 120 (when the satellite 130 operates as a transparent relay node) or the satellite 130 (when the satellite 130 operates as a gNB) . It would be appreciated that although the process flow 200 may be likewise applied to other communication scenarios.

In the process flow 200, the BS 202 determines 210 a measurement configuration for the UE 201. The BS 202 transmits 220 the measurement configuration 222 to the UE 201, and on the other side of communication, the UE 201 receives 224 the measurement configuration 222.

In some embodiments, the UE 201 is in a connected mode, and is in a serving cell provided by the BS 202. In some examples, the UE 201 may enter into a radio resource control (RRC) connected mode by a RRC connection procedure. For example, the serving cell may be an NTN cell. In some example embodiments, the measurement configuration 222 may include a measurement condition. In some examples, the measurement condition may associate with a terrestrial network cell, such as a frequency, a cell, frequencies, cells or the like. In some examples, the measurement configuration 222 may include an identifier (ID) of the terrestrial network cell.

In some embodiments, the terrestrial network cell may correspond to a frequency which associated with one or more cells. In some embodiments, the terrestrial network cell may include a neighboring cell or a non-serving cell. For example, the measurement condition may associate with a neighboring cell or a non-serving cell. For example, the neighboring cell or the non-serving cell may be a non-serving TN cell. As such, the measurement condition is introduced to enable the measurement (s) on the neighboring cell or the non-serving cell in connected mode.

In some example embodiments, the measurement configuration 222 may be carried in a radio resource control (RRC) reconfiguration message, but the present disclosure does not limit this aspect. In some example embodiments, the measurement configuration 222 may be a radio resource management (RRM) measurement configuration. In some example embodiments, the measurement condition may be an area specific condition. For example, the measurement condition may be beam specific or location specific.

In some embodiments, the measurement condition may indicate that a quality of a specific beam on a serving cell is lower than a quality threshold. In some examples, the quality threshold is beam specific, for example, the quality threshold may be called as a beam specific S-measure. In some examples, the measurement configuration 222 may include the quality threshold. In some examples, the measurement configuration 222 may include an indication of the specific beam. In some examples, the indication of the specific beam may be synchronization signal block (SSB) based or channel state information -reference signal (CSI-RS) based. For example, the indication of the specific beam may be indicated as SSB based reference signal received power (RSRP) /reference signal received quality (RSRQ) , or may be indicated as CSI-RS based RSRP/RSRQ. In some examples, the quality of the specific beam may be a RSRP of the specific beam or a RSRQ of the specific beam, but the present disclosure does not limit this aspect.

In some embodiments, the measurement condition may indicate that: a distance between a current location of the UE 201 and a first reference location is smaller than a first distance threshold, and/or, the distance between the current location of the UE 201 and a second reference location is larger than a second distance threshold. For example, the first distance threshold is location specific. For example, the second distance threshold is location specific. In other words, the measurement condition may indicate that the UE is located in a specific area. In some examples, the measurement configuration 222 may include information of the first reference location and/or information of the second reference location. For example, the information of the first reference location and/or information of the second reference location may be represented as longitude and latitude. In some examples, the measurement configuration 222 may include the first distance threshold and/or the second distance threshold. In some other examples, the first reference location, the second reference location, the first distance threshold, or the second distance threshold may be pre-defined or be pre-configured associated with the terrestrial network cell, such as a neighboring cell or a non-serving cell, and thus the signaling overhead may be reduced.

In some example embodiments, the measurement condition may be associated with an information element (IE) “measurement object” . In some examples, the measurement configuration 222 may be under the measurement object, and the measurement object (MeasObjectNR) may be updated as:

In some examples, the measurement configuration 222 may be under an IE “measurement configuration” , and it may configure an association between the measurement condition and the measurement object. For example, the measurement configuration “MeasConfig” may be updated as:

In some example embodiments, the measurement configuration 222 may be carried in the measurement config, measurement object config, or measurement report config. In some examples, the measurement condition may also be a handover condition, which may also be called as a CHO trigger condition or the like.

In the process flow 200, the UE 201 performs 230 a measurement on the associated terrestrial network cell if the measurement condition is met. In some embodiments, if the measurement condition is met, the UE 201 performs a measurement on the associated terrestrial network cell but not on another terrestrial network cell unassociated with the measurement condition. As such, the UE 201 may enable the non-serving cell measurement per measurement object if the associated measurement condition is met.

For example, the measurement condition indicates that a quality of a specific beam of the serving cell is lower than a quality threshold (such as S-measure) , the UE 201 may enable or start the measurement on the associated measurement object if the UE 201 finds out the measurement condition is met. In some example embodiments, the UE 201 may determine (or measure) a quality of a specific beam on the serving cell, and the UE 201 may further determine whether the measurement condition is met. For example, the UE 201 may compare the measured quality of the specific beam on the serving cell with the quality threshold, to determine whether the measurement condition is met.

For another example, the measurement condition indicates that the distance of the current location of the UE 201 and a first reference location is smaller than a first distance threshold, the UE 201 may enable or start the measurement on the associated measurement object if the UE 201 finds out the measurement condition is met. For yet another example, the measurement condition indicates that a distance of the current location of the UE 201 and a first reference location is smaller than a first distance threshold and a distance of the current location of the UE 201 and a second reference location is larger than a second distance threshold, the UE 201 may enable or start the measurement on the associated measurement object if the UE 201 finds out the measurement condition is met. In some example embodiments, the UE 201 may determine the current location of the UE 201, by using GNSS information for example. The UE 201 may further determine the distance between the current location and the first reference location (or the second reference location) , and then determine whether the measurement condition is met.

In some embodiments, the measurement may be against a neighboring cell or a non-serving cell associated with the measurement condition. As such, the UE 201 may enable the non-serving cell (or the neighboring cell) measurement per measurement object if the associated measurement condition is met. As such, the measurement condition may be used to control whether the UE 201 should start or stop performing the non-serving cell (or the neighboring cell) measurement.

In some example embodiments, the UE 201 may determine a quality of the non-serving cell (or the neighboring cell) by measuring. In some embodiments, a measurement event is triggered by a difference of a measurement result on the terrestrial network cell and a measurement result on a serving cell provided by the BS being larger than a first threshold, the measurement result on the serving cell indicating a quality of a specific beam on the serving cell, the specific beam being indicated by the measurement configuration, which may be referred as an enhanced A3 measurement event. In some other embodiments, a measurement event is triggered by the measurement result on the terrestrial network cell being larger than a second threshold and the measurement result on the serving cell being smaller than a third threshold, which may be referred as an enhanced A5 measurement event.

In some examples, the terrestrial network cell may be a neighboring cell and the measurement result may be a quality. In this event, the enhanced A3 measurement event and the enhanced A5 measurement event may be defined as:

Enhanced A3 event: a quality of the neighboring cell -a quality of a specific beam of the serving cell > a first threshold;

Enhanced A5 event: a quality of the neighboring cell > a second threshold, and a quality of a specific beam of the serving cell < a third threshold.

It is understood that the quality of a specific beam of the serving cell may be configured in the measurement event part, but not based on a cell derived quality. Thus, the measurement event may be more accurate.

Alternatively or in addition, as shown in FIG. 2, the UE 201 may transmit 240 a measurement result 242 to the BS 202. On the other side of communication, the BS 202 may receive 244 the measurement result 242. In some example embodiments, the measurement result 242 may include a quality of a specific beam of the serving cell, and/or a quality of the non-serving cell (or the neighboring cell) .

Alternatively or in addition, the UE 201 may switch from the serving cell to a target cell, where the target cell may be the terrestrial network cell associated with the measurement condition. In some embodiments, the measurement condition may also be a handover condition, as thus, if the measurement condition is met, the UE 201 switch to the target cell. For example, the BS 202 may transmit a condition handover command (or switch command) to the UE 201, the condition handover command may indicate that the handover condition is the same as the measurement condition comprised in the measurement configuration.

In some examples, the terrestrial network cell includes a neighboring cell, i.e., the measurement condition is associated with the neighboring cell. Then the UE 201 may switch to the associated neighboring cell if the measurement condition is met. In some examples, the associated neighboring cell may be a candidate cell for handover. As such, the measurement condition may be used as handover condition for triggering a cell handover.

Based on the embodiments with reference to FIG. 2, the UE 201 may perform a measurement on a terrestrial network cell associated with the measurement condition if the measurement condition is met. As such, there is no need for the UE to perform the measurement on all neighboring cells, thus the power consumption may be reduced. Additionally, the measurement condition may also be used as a handover condition, as such, the handover procedure may be simplified and the efficiency may be improved.

FIG. 3 illustrates another example network environment 300 in which some example embodiments of the present disclosure may be implemented. As shown in FIG. 3, the satellite 130 may be a non-terrestrial node, such as an NTN gNB. The satellite 130 may provide an NTN cell 310, and the UE 110 is located within the NTN cell 310. There are two neighboring cells of the NTN cell 310, i.e., a TN cell 320 and a TN cell 330.

In NTN cell 310, there may be different geographic areas with different beams. For example, as shown in FIG. 3, the area 312 may correspond to a beam #1, and the area 314 may correspond to a beam #2.

For the UE 110, when it is located in different geographic areas, the neighboring cell for the UE 110 may be different. Therefore, there is no need to start the measurement on all the non-serving cells at the same time. Instead, it is only necessary for the UE 110 to measure the non-serving cell located in that particular geographic area. Example embodiments related to the measurement will be further described with reference to FIG. 4.

FIG. 4 illustrates an example process 400 of measurement in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the example process 400 will be described with reference to FIG. 3.

In the process 400, the UE 110 may connect to an NTN. For example, the UE 110 may enter to an RRC connected state through an RRC connection procedure with the gNB of the NTN cell 310, for example, the gNB of the NTN cell 310 may be the satellite 130. The gNB of the NTN cell 310 may transmit an RRC reconfiguration with the measurement configuration to the UE 110. The measurement configuration may include a measurement condition associated with a measurement object. In some example embodiments, the UE 110 may store the measurement configuration.

For example, the measurement object#1 may indicate that the condition#1 is beam#1 < Smeas, and the condition#1 is associated with TN-cell-1. For example, the measurement object#2 may indicate that the condition#2 is beam#2 < Smeas, and the condition#2 is associated with TN-cell-2. By referring to FIG. 3, it is assumed that beam#1 corresponds to the area 312 and beam#2 corresponds to the area 314, TN-cell-1 is the TN cell 320 and TN-cell-2 is the TN cell 330.

The UE 110 may determine a quality of beam#1 of the serving cell (NTN cell 310 in FIG. 3) , and further determine that beam#1 < Smeas. That is, condition#1 is met. Additionally, the UE 110 may start the measurement on TN-cell-1 (i.e., TN cell 320 in FIG. 3) which is associated with condition#1.

As such, there is no need for the UE 110 to measure all non-serving cells, and the power consumption can be reduced. In some example embodiments, the measurement condition is beam based condition, and it may also be used to control the measurement for CHO trigger condition. Example embodiments related to the measurement will be further described with reference to FIG. 5.

FIG. 5 illustrates an example process 500 of handover in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the example process 500 will be described with reference to FIG. 3.

In the process 500, the UE 110 may connect to an NTN. For example, the UE 110 may enter to an RRC connected state through an RRC connection procedure with the gNB of the NTN cell 310, for example, the gNB of the NTN cell 310 may be the satellite 130. The gNB of the NTN cell 310 may transmit a CHO command to the UE 110. The CHO command indicates that the candidate cell is TN-cell-1 (i.e., TN cell 320 in FIG. 3) and the CHO condition is MID#1, where MID#1 refers to a measurement configuration. The measurement configuration may include a measurement condition (be used as a CHO condition in FIG. 5) associated with a measurement object. In some example embodiments, the UE 110 may store the measurement configuration.

For example, the measurement configuration may indicate: measurement object#1, TN-cell-1, condition#1 is beam#1 < Smeas. In other words, MID#1 indicates the measurement object#1, the condition#1 is beam#1 < Smeas, and the condition#1 is associated with TN-cell-1. It is understood that MID#1 in FIG. 5 is similar as part of the measurement configuration in FIG. 4. By referring to FIG. 3, it is assumed that beam#1 corresponds to the area 312 and TN-cell-1 is the TN cell 320.

In the process 500, the measurement condition is also used as a CHO condition, thus condition#1 is met means that the CHO condition is met. The UE 110 may perform a handover to TN-cell-1 (i.e., TN cell 320 in FIG. 3) which is associated with condition#1. The UE 110 may connect to TN-cell-1 if the CHO is completed. As such, the handover procedure may be simplified and the power consumption can be reduced.

FIG. 6 illustrates a flowchart of a method 600 implemented at a UE in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 600 will be described from the perspective of the UE 110/201.

At block 610, the UE 110/201 located in a non-terrestrial network cell receives, from a BS, a measurement configuration comprising a measurement condition. At block 620, if the measurement condition is met, the UE 110/201 performs a measurement on a terrestrial network cell associated with the measurement condition, without performing a measurement on a further terrestrial network cell unassociated with the measurement condition.

In some example embodiments, the measurement condition may indicate one or more of: a quality of a specific beam on a serving cell is lower than a quality threshold, a distance between a current location of the UE and a first reference location is smaller than a first distance threshold, or a distance between the current location of the UE and a second reference location is larger than a second distance threshold.

In some example embodiments, the measurement configuration comprising at least one of: an identifier of the terrestrial network cell associated with the measurement condition, the quality threshold, the first distance threshold, the second distance threshold, information of the first reference location, information of the second reference location, or an indication of the specific beam.

In some example embodiments, the indication of the specific beam is: synchronization signal block (SSB) based, or channel state information -reference signal (CSI-RS) based. In some example embodiments, a serving cell provided by the BS comprises an NTN cell, and the terrestrial network cell comprises a TN cell. In some example embodiments, the UE 110/201 reports a measurement result to the BS.

In some example embodiments, a measurement event is triggered by one or more of: a difference of a measurement result on the terrestrial network cell and a measurement result on a serving cell provided by the BS being larger than a first threshold, the measurement result on the serving cell indicating a quality of a specific beam on the serving cell, the specific beam being indicated by the measurement configuration, or the measurement result on the terrestrial network cell being larger than a second threshold and the measurement result on the serving cell being smaller than a third threshold.

In some example embodiments, if the measurement condition is met, the UE 110/201 performs a cell switching from a serving cell to the terrestrial network cell.

FIG. 7 illustrates a flowchart of a method 700 implemented at a BS in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 700 will be described from the perspective of the BS 202.

At block 710, the BS 202 determines, for a UE located in a non-terrestrial network cell, a measurement configuration comprising a measurement condition, the measurement condition when met causing the UE to perform a measurement on a terrestrial network cell associated with the measurement condition without performing a measurement on a further terrestrial network cell unassociated with the measurement condition. At block 720, the BS 202 transmits the measurement configuration to the UE.

In some example embodiments, the indication of the specific beam is: SSB based, or CSI-RS based. In some example embodiments, a serving cell provided by the BS 202 comprises an NTN cell, and the terrestrial network cell comprises a TN cell. In some example embodiments, the BS 202 receives a measurement result from the UE.

FIG. 8 illustrates a simplified block diagram of a device 800 that is suitable for implementing some example embodiments of the present disclosure. The device 800 may be provided to implement the communication device, for example the UE 110/201, or the BS 202. As shown, the device 800 includes a processor 810, a memory 820 coupled to the processor 810, and a transceiver 840 coupled to the processor 810.

The transceiver 840 is for bidirectional communications. The transceiver 840 is coupled to at least one antenna to facilitate communication. The transceiver 840 can comprise a transmitter circuitry (e.g., associated with one or more transmit chains) and/or a receiver circuitry (e.g., associated with one or more receive chains) . The transmitter circuitry and receiver circuitry can employ common circuit elements, distinct circuit elements, or a combination thereof.

The processor 810 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 800 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

The memory 820 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 824, an electrically programmable read only memory (EPROM) , a flash memory, a hard disk, a compact disc (CD) , a digital video disk (DVD) , and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 822 and other volatile memories that will not last in the power-down duration.

A computer program 830 includes computer executable instructions that are executed by the associated processor 810. The program 830 may be stored in the ROM 824. The processor 810 may perform any suitable actions and processing by loading the program 830 into the RAM 822.

The embodiments of the present disclosure may be implemented by means of the program 830 so that the device 800 may perform any process of the disclosure as discussed with reference to FIGS. 2 and 4-5. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the method 600 as described above with reference to FIG. 6 and/or the method 700 as described above with reference to FIG. 7.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

A baseband processor of a user equipment (UE) configured to perform operations comprising:

receiving, using a transceiver of the UE and from a base station (BS) , a measurement configuration comprising a measurement condition, the UE being located in a non-terrestrial network cell; and

in accordance with a determination that the measurement condition is met, performing a measurement on a terrestrial network cell associated with the measurement condition, without performing a measurement on a further terrestrial network cell unassociated with the measurement condition.
The processor of the UE of claim 1, wherein the measurement condition indicates at least one of:

a quality of a specific beam on a serving cell is lower than a quality threshold,

a distance between a current location of the UE and a first reference location is smaller than a first distance threshold, or

a distance between the current location of the UE and a second reference location is larger than a second distance threshold.
The processor of the UE of claim 2, wherein the measurement configuration comprising at least one of:

an identifier of the terrestrial network cell associated with the measurement condition,

the quality threshold,

the first distance threshold,

the second distance threshold,

information of the first reference location,

information of the second reference location, or

an indication of the specific beam.
The processor of the UE of claim 3, wherein the indication of the specific beam is:

synchronization signal block (SSB) based, or

channel state information -reference signal (CSI-RS) based.
The processor of the UE of any of claims 1-4, wherein the processor is further configured to perform operations comprising:

reporting, using the transceiver, a measurement result to the BS.
The processor of the UE of any of claims 1-5, wherein a measurement event is triggered by at least one of:

a difference of a measurement result on the terrestrial network cell and a measurement result on a serving cell provided by the BS being larger than a first threshold, the measurement result on the serving cell indicating a quality of a specific beam on the serving cell, the specific beam being indicated by the measurement configuration, or

the measurement result on the terrestrial network cell being larger than a second threshold and the measurement result on the serving cell being smaller than a third threshold.
The processor of the UE of any of claims 1-6, wherein the processor is further configured to perform operations comprising:

in accordance with a determination that the measurement condition is met, performing a cell switching from a serving cell to the terrestrial network cell.
A baseband processor of a base station (BS) configured to perform operations comprising:

determining, for a user equipment (UE) being located in a non-terrestrial network cell, a measurement configuration comprising a measurement condition, the measurement condition when met causing the UE to perform a measurement on a terrestrial network cell associated with the measurement condition without performing a measurement on a further terrestrial network cell unassociated with the measurement condition; and

transmitting, using a transceiver of the BS, the measurement configuration to the UE.
The processor of the BS of claim 8, wherein the measurement condition indicates at least one of:

a quality of a specific beam on a serving cell is lower than a quality threshold,

a distance between a current location of the UE and a first reference location is smaller than a first distance threshold, or

a distance between the current location of the UE and a second reference location is larger than a second distance threshold.
The processor of the BS of claim 9, wherein the measurement configuration comprising at least one of:

an identifier of the terrestrial network cell associated with the measurement condition,

the quality threshold,

the first distance threshold,

the second distance threshold,

information of the first reference location,

information of the second reference location, or

an indication of the specific beam.
The processor of the BS of claim 10, wherein the indication of the specific beam is:

synchronization signal block (SSB) based, or

channel state information -reference signal (CSI-RS) based.
The processor of the BS of any of claims 8-11, wherein the processor is further configured to perform operations comprising:

receiving, using the transceiver, a measurement result from the UE.
A user equipment (UE) comprising:

a transceiver configured to communicate with a network; and

a processor communicatively coupled to the transceiver and configured to perform operations comprising:

receiving, using the transceiver and from a base station (BS) , a measurement configuration comprising a measurement condition, the UE being located in a non-terrestrial network cell; and

in accordance with a determination that the measurement condition is met, performing a measurement on a terrestrial network cell associated with the measurement condition, without performing a measurement on a further terrestrial network cell unassociated with the measurement condition.
The UE of claim 13, wherein the measurement condition indicates at least one of:

a quality of a specific beam on a serving cell is lower than a quality threshold,

a distance between a current location of the UE and a first reference location is smaller than a first distance threshold, or

a distance between the current location of the UE and a second reference location is larger than a second distance threshold.
The UE of claim 14, wherein the measurement configuration comprising at least one of:

an identifier of the terrestrial network cell associated with the measurement condition,

the quality threshold,

the first distance threshold,

the second distance threshold,

information of the first reference location,

information of the second reference location, or

an indication of the specific beam.
The UE of claim 15, wherein the indication of the specific beam is:

synchronization signal block (SSB) based, or

channel state information -reference signal (CSI-RS) based.
The UE of any of claims 13-16, wherein the processor is further configured to perform operations comprising:

reporting, using the transceiver, a measurement result to the BS.
The UE of any of claims 13-17, wherein a measurement event is triggered by at least one of:

a difference of a measurement result on the terrestrial network cell and a measurement result on a serving cell provided by the BS being larger than a first threshold, the measurement result on the serving cell indicating a quality of a specific beam on the serving cell, the specific beam being indicated by the measurement configuration, or

the measurement result on the terrestrial network cell being larger than a second threshold and the measurement result on the serving cell being smaller than a third threshold.
The UE of any of claims 13-18, wherein the processor is further configured to perform operations comprising:

in accordance with a determination that the measurement condition is met, performing a cell switching from a serving cell to the terrestrial network cell.
A base station (BS) comprising:

a transceiver configured to communicate with a network; and

a processor communicatively coupled to the transceiver and configured to perform operations comprising:

determining, for a user equipment (UE) , a measurement configuration comprising a measurement condition, the measurement condition when met causing the UE to perform a measurement on a terrestrial network cell associated with the measurement condition without performing a measurement on a further terrestrial network cell unassociated with the measurement condition; and

transmitting, using the transceiver, the measurement configuration to the UE.
The BS of claim 20, wherein the measurement condition indicates at least one of:

a quality of a specific beam on a serving cell is lower than a quality threshold,

a distance between a current location of the UE and a first reference location is smaller than a first distance threshold, or

a distance between the current location of the UE and a second reference location is larger than a second distance threshold.
The BS of claim 21, wherein the measurement configuration comprising at least one of:

an identifier of the terrestrial network cell associated with the measurement condition,

the quality threshold,

the first distance threshold,

the second distance threshold,

information of the first reference location,

information of the second reference location, or

an indication of the specific beam.
The BS of claim 22, wherein the indication of the specific beam is:

synchronization signal block (SSB) based, or

channel state information -reference signal (CSI-RS) based.
The BS of any of claims 20-23, wherein the processor is further configured to perform operations comprising:

receiving, using the transceiver, a measurement result from the UE.