WO2018228527A1

WO2018228527A1 - Method, terminal device and network device for handling coexistence of terminal devices with different sidelink capability sets

Info

Publication number: WO2018228527A1
Application number: PCT/CN2018/091481
Authority: WO
Inventors: Zhang Zhang; Yunxi LI; Stefano Sorrentino
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2017-06-16
Filing date: 2018-06-15
Publication date: 2018-12-20

Abstract

Method, terminal device and network device are disclosed for handling coexistence of terminal devices with different sidelink capability sets. According to an embodiment, a first terminal device with a first sidelink capability set obtains capability related information of one or more second terminal devices. The first terminal device determines sidelink capability sets of the one or more second terminal devices from the obtained capability related information. The first terminal device determines, from the first sidelink capability set, a capability subset for use in sidelink transmission to a second terminal device, based at least on the determined sidelink capability sets.

Description

METHOD, TERMINAL DEVICE AND NETWORK DEVICE FOR HANDLING COEXISTENCE OF TERMINAL DEVICES WITH DIFFERENT SIDELINK CAPABILITY SETS

Technical Field

Embodiments of the disclosure generally relate to wireless communication, and, more particularly, to a method, a terminal device and a network device for handling coexistence of terminal devices with different sidelink capability sets.

Background

Device-to-device (D2D) communication in cellular networks is defined as direct communication between two mobile users without traversing the base station or core network. In Release 14 of the 3 ^rd generation partnership project (3GPP) , the extensions for D2D work comprise support for vehicle-to-everything (V2X) communication. There are mainly three use cases defined for V2X: vehicle-to-vehicle (V2V) , vehicle-to-pedestrian (V2P) and vehicle-to-infrastructure/network (V2I/N) . Thus, V2X communication includes any combination of direct communication between vehicles, pedestrians and infrastructure.

Because long term evolution (LTE) has economies of scale and may enable tighter integration between V2I and V2V/V2P communications, providing an LTE-based V2X interface may be economically advantageous, as compared to using a dedicated V2X technology. FIG. 1 shows V2X scenarios for an LTE-based network. V2V covers LTE-based communication between vehicles, either via Uu or sidelink. The Uu refers to the radio interface between a user equipment (UE) and an evolved node B (eNB) . The sidelink may refer to a direct communication interface between UEs (also referred to as PC5 interface in LTE) . V2P covers LTE-based communication between a vehicle and a device carried by an individual (e.g. handheld terminal carried by a pedestrian, cyclist, driver or passenger) , either via Uu or sidelink. V2I/N covers LTE-based communication between a vehicle and a roadside unit/network. A roadside unit (RSU) is a transportation infrastructure entity (e.g. an entity transmitting speed notifications) that communicates with V2X capable UEs over sidelink. For V2N, the communication is performed via Uu.

A basic set of requirements for evolved packet system (EPS) to support V2X applications have been specified for LTE. These requirements are considered sufficient for vehicles to exchange their own status information, such as position, speed and moving direction, with other nearby vehicles, infrastructure nodes and/or pedestrians. Also, these requirements fulfill the need to disseminate imminent warning messages to nearby entities in time. The capability of EPS to support these requirements will expedite the adoption of 3GPP connectivity by vehicles.

Despite the basic set of requirements for 3GPP system to support V2X service, it is considered growingly important among telecommunication industry and automotive industry that its evolution is necessary. Because automotive industries have begun to see V2X applications beyond unidirectional distribution of status information of vehicles, 3GPP system needs to increase its capability enough to meet key performance indicators (KPIs) that emerging V2X applications may require. Thus, the studies on enhanced V2X (eV2X) have been started.

Summary

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

One of the objects of the disclosure is to provide a solution applicable to eV2X communication.

According to one aspect of the disclosure, there is provided a method implemented at a first terminal device with a first sidelink capability set. The method comprises obtaining capability related information of one or more second terminal devices. The method further comprises determining sidelink capability sets of the one or more second terminal devices from the obtained capability related information. The method further comprises determining, from the first sidelink capability set, a capability subset for use in sidelink transmission to a second terminal device, based at least on the determined sidelink capability sets.

According to the above embodiment, terminal devices with different sidelink capability sets can be enabled to properly perform sidelink communication with each other.

In an embodiment of the disclosure, determining the capability subset may comprise, when a capability in the first sidelink capability set is included in at least a predetermined percentage of the sidelink capability sets of the one or more second terminal devices, determining the capability as a member of the capability subset.

In an embodiment of the disclosure, the capability related information may comprise a capability indication that indicates a sidelink capability set of a second terminal device. Alternatively or additionally, the capability related information may comprise a service indication that indicates a service set suppored by a second terminal device, and determining the sidelink capability sets of the one or more second terminal devices may comprise deducing the sidelink capability sets of the one or more second terminal devices from the service indications of the one or more second terminal devices.

In an embodiment of the disclosure, the method may further comprise acquiring position related information of the one or more second terminal devices. Determining the capability subset may be performed based further on the acquired position related information.

In an embodiment of the disclosure, determining the capability subset may comprise selecting, from the one or more second terminal devices, at least one second terminal device whose position related information meets a predetermined condition. Determining the capability subset may comprise, when a capability in the first sidelink capability set is included in at least a predetermined percentage of the sidelink capability set of the selected at least one second terminal device, determining the capability as a member of the capability subset.

In an embodiment of the disclosure, the position related information may comprise a sidelink reference signal received power (S-RSRP) from a second terminal device, and the predetermined condition may be that the S-RSRP is above a predetermined threshold. Alternatively or additionally, the position related information may comprise a position indication that indicates a position of a second terminal device, and the predetermined condition may be that the position of the second terminal device is within a predetermined distance range of the first terminal device.

In an embodiment of the disclosure, the predetermined percentage may be set in the first terminal device, or may be signaled from a base station serving the first terminal device. The predetermined percentage may be set depending on at least one of: the service to which the predetermined percentage is to apply, and the way by which the sidelink capability sets of the one or more second terminal devices are determined.

In an embodiment of the disclosure, the predetermined threshold or the predetermined distance range may be set in the first terminal device, or may be signaled from a base station serving the first terminal device. The predetermined threshold or the predetermined distance range may be set depending on the service to which the predetermined threshold or the predetermined distance range is to apply.

In an embodiment of the disclosure, the obtaining may be implemented by at least one of: detecting a capability indication from sidelink control information (SCI) over sidelink; detecting a capability indication from a message header over sidelink; detecting a capability indication from a message body over sidelink or downlink; detecting a service indication from a message body over sidelink or downlink; and retrieving capability related information of a second terminal device from a memory of the first terminal device based on an identity (ID) of the second terminal device. In such imbodiment, the previously obtained capability related information and ID of the second terminal device are stored in association in the memory of the first terminal device.

In an embodiment of the disclosure, the acquiring may be implemented by at least one of: measuring an S-RSRP; and detecting, over sidelink or downlink, a position indication from a message body which is the same or different than that for the capability related information.

In an embodiment of the disclosure, the method may further comprise transmitting capability related information of the first terminal device.

In an embodiment of the disclosure, before the obtaining, the transmitting is performed with a legacy sidelink format. After determining the capability subset, the transmitting is performed with a sidelink format compatible with the determined capability subset.

In an embodiment of the disclosure, the transmitting, obtaining, determining the sidelink capability sets and determining the capability subset are performed sequentially and iteratively. In each iteration, a portion of capability indications is transmitted with a sidelink format compatible with the capabilities indicated by the portion. The portion of capability indications in one iteration may be a superset of the portion in previous iteration (s) .

In an embodiment of the disclosure, the transmitting is performed periodically or in response to a trigger event. The periodicity, or the periodicity configuration rule, or the trigger event may be predefined in the first terminal device, or may be signaled from a base station serving the first terminal device. The periodicity is set depending on at least one of a speed and a carrier frequency of the first terminal device, and the trigger event is set depending on at least one of a speed and a position of the first terminal device.

According to another aspect of the disclosure, there is provided a method implemented at a network device. The method comprises obtaining capability related information of a plurality of terminal devices. The plurality of terminal devices comprises a first terminal device and one or more second terminal devices. The method further comprises determining sidelink capability sets of the plurality of terminal devices from the obtained capability related information. The method further comprises determining, from a first sidelink capability set of the first terminal device, a capability subset for use in sidelink transmission from the first terminal device to a second terminal device, based at least on the determined sidelink capability sets of the one or more second terminal devices. The method further comprises informing the first terminal device of the determined capability subset.

In an embodiment of the disclosure, the capability related information may comprise a capability indication that indicates a sidelink capability set of a terminal device. Alternatively or additionally, the capability related information may comprise a service indication that indicates a service set suppored by a terminal device, and determining the sidelink capability sets of the plurality of terminal devices may comprise deducing the sidelink capability sets of the plurality of terminal devices from the service indications of the plurality of terminal devices.

In an embodiment of the disclosure, the method may further comprise acquiring position related information of the plurality of terminal devices. Determining the capability subset may be performed based further on the acquired position related information.

In an embodiment of the disclosure, determining the capability subset may comprise selecting, from the one or more second terminal devices, at least one second terminal device whose position related information meets a predetermined condition. Determining the capability subset further may comprise, when a capability in the first sidelink capability set is included in at least a predetermined percentage of the sidelink capability set of the selected at least one second terminal device, determining the capability as a member of the capability subset.

In an embodiment of the disclosure, the position related information may comprise a position indication that indicates a position of a terminal device, and the predetermined condition may be that the position of the second terminal device is within a predetermined distance range of the first terminal device.

In an embodiment of the disclosure, the obtaining may comprise at least one of: detecting a capability indication from a message body over uplink; detecting a service indication from a message body over uplink; and detecting a capability indication from radio resource control (RRC) signaling over uplink.

In an embodiment of the disclosure, the acquiring may comprise detecting, over uplink, a position indication from a message body which is the same or different than that for the capability related information.

In an embodiment of the disclosure, the network device may be a base station serving the first terminal device. The obtaining may comprise at least one of: receiving capability related information from a second terminal device; and receiving, from a neighboring base station, capability related information of a second terminal device.

In an embodiment of the disclosure, the network device may be a central server. The capability related information of the plurality of terminal devices may be obtained from a plurality of base stations serving the plurality of terminal devices.

According to another aspect of the disclosure, there is provided a first terminal device. The first terminal device comprises at least one processor and at least one memory. The at least one memory contains instructions executable by the at least one processor, whereby the first terminal device is operative to obtain capability related information of one or more second terminal devices. The first terminal device is further operative to determine sidelink capability sets of the one or more second terminal devices from the obtained capability related information. The first terminal device is further operative to determine, from a first sidelink capability set of the first terminal device, a capability subset for use in sidelink transmission to a second terminal device, based at least on the determined sidelink capability sets.

According to another aspect of the disclosure, there is provided a network device. The network device comprises at least one processor and at least one memory. The at least one memory contains instructions executable by the at least one processor, whereby the network device is operative to obtain capability related information of a plurality of terminal devices. The plurality of terminal devices comprises a first terminal device and one or more second terminal devices. The network device is further operative to determine sidelink capability sets of the plurality of terminal devices from the obtained capability related information. The network device is further operative to determine, from a first sidelink capability set of the first terminal device, a capability subset for use in sidelink transmission from the first terminal device to a second terminal device, based at least on the determined sidelink capability sets of the one or more second terminal devices. The network device is further operative to inform the first terminal device of the determined capability subset.

According to another aspect of the disclosure, there is provided a computer program product. The computer program product comprises instructions which when executed by at least one processor, cause the at least one processor to perform the method according to the above aspect.

According to another aspect of the disclosure, there is provided a computer readable storage medium. The computer readable storage medium comprises instructions which when executed by at least one processor, cause the at least one processor to perform the method according to the above aspect.

According to another aspect of the disclosure, there is provided a first terminal device. The first terminal device comprises an obtaining module for obtaining capability related information of one or more second terminal devices. The first terminal device further comprises a first determination module for determining sidelink capability sets of the one or more second terminal devices from the obtained capability related information. The first terminal device further comprises a second determination module for determining, from the first sidelink capability set, a capability subset for use in sidelink transmission to a second terminal device, based at least on the determined sidelink capability sets.

According to another aspect of the disclosure, there is provided a network device. The network device comprises an obtaining module for obtaining capability related information of a plurality of terminal devices. The plurality of terminal devices comprises a first terminal device and one or more second terminal devices. The network device further comprises a first determination module for determining sidelink capability sets of the plurality of terminal devices from the obtained capability related information. The network device further comprises a second determination module for determining, from a first sidelink capability set of the first terminal device, a capability subset for use in sidelink transmission from the first terminal device to a second terminal device, based at least on the determined sidelink capability sets of the one or more second terminal devices. The network device further comprises an informing module for informing the first terminal device of the determined capability subset.

Brief Description of the Drawings

These and other objects, features and advantages of the disclosure will become apparent from the following detailed description of illustrative embodiments thereof, which are to be read in connection with the accompanying drawings.

FIG. 1 shows V2X scenarios for an LTE-based network;

FIG. 2 is a diagram illustrating a first solution of the disclosure;

FIG. 3 is a diagram illustrating a second solution of the disclosure;

FIG. 4 is a diagram illustrating a third solution of the disclosure;

FIG. 5 is a diagram illustrating a fourth solution of the disclosure;

FIG. 6 is a flowchart illustrating a method at terminal device side according to an embodiment of the disclosure;

FIG. 7 is a flowchart illustrating a method at terminal device side according to another embodiment of the disclosure;

FIGs. 8A and 8B are flowcharts each illustrating a method at terminal device side according to an embodiment of the disclosure;

FIG. 9 is a flowchart illustrating a method at network side according to an embodiment of the disclosure;

FIG. 10 is a flowchart illustrating a method at network side according to another embodiment of the disclosure;

FIG. 11 is a block diagram illustrating a terminal device according to an embodiment of the disclosure;

FIG. 12 is a block diagram illustrating a network device according to an embodiment of the disclosure;

FIG. 13 is a block diagram illustrating a terminal device according to another embodiment of the disclosure; and

FIG. 14 is a block diagram illustrating a network device according to another embodiment of the disclosure.

Detailed Description

For the purpose of explanation, details are set forth in the following description in order to provide a thorough understanding of the embodiments disclosed. It is apparent, however, to those skilled in the art that the embodiments may be implemented without these specific details or with an equivalent arrangement.

For eV2X communication, several new use cases have been foreseen. They include support for vehicle platoon, automotive sensor and state map sharing, support for remote driving, automated cooperative driving for short distance grouping, collective perception of environment, 3D video composition for V2X scenario, and so on. Accordingly, transmission of short messages about vehicles’own status data will be complemented with transmission of larger messages containing raw sensor data, vehicles’intention data, coordination and confirmation of future manoeuvre and so on.For these advanced applications, the expected requirements to meet the needed data rate, reliability, latency, communication range and speed are made more stringent.

To meet the more stringent performance requirements, a new study item on eV2X has been started in Release 15 of 3GPP for both enhanced LTE (eLTE) and new radio (NR) . Potential improvements may include multiple carriers on sidelink, short transmission time interval (TTI) on sidelink, multi-antenna support on sidelink, NR support on sidelink, high order modulation such as 64-quadrature amplitude modulation (64-QAM) .

In this way, different UEs with different sidelink capability sets may coexist. For example, some UEs may support 64-QAM on sidelink, some UEs may support short TTI on sidelink, some UEs may support both 64-QAM and short TTI on sidelink, while some UEs may only support legacy sidelink transmission without any new feature. Thus, it could happen that the sidelink transmission could not be correctly received or understood if different UEs with different sidelink capability sets coexist. For example, a sidelink transmission adopting 64-QAM, short TTI and/or NR could not be received by other UEs if they do not have the corresponding capabilities. In view of this, a solution is needed to handle this coexistence scenario while enabling the use of new features whenever possible.

The present disclosure proposes a plurality of solutions for handling coexistence of UEs with different sidelink capability sets. These solutions can be applied to a wireless communication system comprising a base station (BS) supporting communication related services in a coverage area which may also be referred to as a cell. The BS is also capable of communicating with at least one UE within the coverage area. The communications between the BS and the at least one UE may employ any wireless communication standards such as CDMA, TDMA, FDMA, OFDMA and so on. The BS may be, for example, an eNB in LTE or a gNB in NR. The UE may be referred to as, for example, terminal device, mobile station, mobile unit, subscriber station, wireless terminal, terminal, device, or the like. The UE may be mobile or stationary. It may be, for example, a wireless handheld device such as a wireless phone, a computer with a wireless connection to a network, a wireless plug-in accessory, or the like. Hereinafter, the solutions will be described in detail with reference to FIGs. 2 to 5. Although these solutions are described in the context of (e) V2X scenarios, those skilled in the art can understand that the principle of the present disclose can also be applied to any other direct communication scenarios.

FIG. 2 is a diagram illustrating a first solution of the disclosure. There are shown two entities, UE 1 and UE 2, in this solution. The UE 2 represents a UE that surrounds or is in the vicinity of the UE 1. Thus, there may be one or more UEs 2 although only one UE 2 is shown for brevity. The UE 1 has a first sidelink capability set that includes one or more sidelink capabilities supported by the UE 1. Each of the one or more UEs 2 has its own sidelink capability set, called as second sidelink capability set, that includes its supported one or more sidelink capabilities. Any one of the one or more UEs 2 may have a same or different sidelink capability set than the UE 1. In other words, any one of the one or more second sidelink capability sets may be the same or different than the first sidelink capability set. Thus, it would be desirable to handle coexistence between the UE 1 and the one or more UEs 2.

At step 202a, the UE 2 transmits its capability related information. The capability related information of a UE refers to such information from which the UE’s sidelink capability set can be determined. As an example, a UE’s capability related information may be a capability indication that indicates the UE’s sidelink capability set. The capability indication may take the form of a field of N bits. Each bit indicates whether a certain (e.g. new) sidelink capability is supported or not. The examples of the sidelink capability may include 64-QAM, short TTI, multiple carriers on sidelink, multi-antenna support on sidelink, NR support on sidelink, and so on. Optionally, a bit may be introduced to the field to just indicate whether the UE is an old Release UE (e.g. where the 3GPP standardization work has been finished) or a new Release UE (e.g. where the 3GPP standardization work is ongoing) .

As another example, a UE’s capability related information may be a service indication that indicates a service set including one or more services supported by the UE. Similar to the capability indication, the service indication may also take the form of a field of N bits. Each bit indicates whether a certain (e.g. new) service is supported or not. The examples of the service may include V2X service, eV2X service, and so on.Since different services may generally have different performance requirements and thus need different capabilities to run the services properly, a UE’s sidelink capability set can be deduced from the service indication.

In this first solution, the capability related information is transmitted over sidelink. This can be done in various ways. As a first option, a capability indication may be transmitted in sidelink control information (SCI) . As a second option, a capability indication may be transmitted in the header of a message such as (e) V2X message. For example, the indication may be added into the link layer header such as media access control/packet data convergence protocol (MAC/PDCP) header.

In the above first and second options, it is possible that the capability indication is not always transmitted. For example, a presence bit may be introduced to indicate whether the capability indication is transmitted or not. This presence bit may be used to indicate whether the UE is an old Release UE or a new Release UE. Further, it may be preferred that the presence bit and/or the release indicating bit is put in SCI and/or a message header using a reserved bit.

As a third option, a capability indication may be transmitted in the body of a message such as a general or special (e) V2X message. As a fourth option, a service indication may be transmitted in the body of a message such as a general or special (e) V2X message.

The above first to fourth transmission options may be used in any combination. For example, some sidelink capability indication bits may be transmitted in SCI, some may be transmitted in the header of (e) V2X message, while some may be transmitted in the body of (e) V2X message.

Optionally, the transmission of the capability related information may be periodical, or triggered on demand. The periodicity may be set depending on factors such as the UE’s speed, carrier frequency, and so on. The periodicity or the rules for configuring the periodicity may be predefined in the UE, or may be configured by the network and informed to the UE through suitable ways such as via system information block (SIB) or dedicated signaling.

The transmission (e.g. a short transmission) may be triggered depending on factors such as the UE’s position (e.g. the UE moves to the proximity of a special area such as street cross) , speed, speed change, and so on. The triggering of transmission may be conducted by the UE or by the network. For example, a rule set for triggering the transmission may be predefined in the UE, or may be configured by the network and informed to the UE through suitable ways such as via SIB or dedicated signaling.

Then, at step 202c, the UE 1 receives the capability related information. Correspondingly to the first to fourth options above, a capability indication may be detected from SCI or a message header or a message body, or a service indication may be detected from a message body.

Further, if the UE 2’s capability related information has been received previously, it may be stored in association with the UE 2’s identity (ID) in the UE 1’s memory. In this way, the UE 1 may obtain the UE 2’s capability related information by retrieving it from the memory based on the UE 2’s ID, without receiving it again. For example, the UE 1 may remember a UE 2’s link layer ID such as proximity-based service (ProSe) ID detected in (e) V2X message. Later on (at least within a certain time period) , the UE 1 can retrieve the UE 2’s capability indication based on the link layer ID.

Optionally, at step 202’a, the UE 2 may transmit its position related information. Correspondingly, at step 202’c, the UE 1 may receive the position related information. Although step 202’a is shown to be subsequent to step 202a, it may also be performed simultaneously with or prior to step 202a.

The position related information of a UE refers to such information from which the UE’s position can be determined. As an example, the position related information may be the quality of reference signals received by the UE 1 from the UE 2, such as sidelink reference signal received power (S-RSRP) . Since the S-RSRP varies depending on the distance between the UE 1 and the UE 2, it can reflect the UE 2’s position.

As another example, a UE’s position related information may be a position indication that indicates the UE’s position. The position indication may be transmitted in the body of a message such as a general or special (e) V2X message. Correspondingly, the position indication may be detected from the body of the message. It should be noted that the capability indication and the position indication may be contained in the same message or in different messages.

Then, at step 204, the UE 1 determines sidelink capability sets of the one or more UEs 2 from the obtained capability related information. In case the capability related information takes the form of a capability indication, the UEs 2’sidelink capability sets can be determined directly from their capability indications. In case the capability related information takes the form of a service indication, the UEs 2’sidelink capability sets can be deduced from their service indications. For example, some (e) V2X services have high performance requirements and thus may only be supported when certain advanced radio features are available on sidelink. Therefore, a UE’s sidelink capabilities can be deduced based on its supported (e) V2X services indicated in (e) V2X message.

Then, at step 206, the UE 1 determines, from its sidelink capability set, a capability subset for use in its sidelink transmission to UE 2, based on the determined sidelink capability sets. The capability subset includes one or more members all of which belong to the sidelink capability set. Thus, the size of the capability subset may be smaller than or equal to that of the sidelink capability set.

Step 206 may be done in such a way that if a capability in the UE 1’s sidelink capability set is included in at least a predetermined percentage of the one or more UEs 2’sidelink capability sets, the capability is determined as a member of the capability subset.

The predetermined percentage may be service specific. That is, different services may have different predetermined percentages for determining the capability subset. Further, the predetermined percentage may be set depending on the way by which the one or more UEs 2’sidelink capability sets are determined, such as depending on whether they are detected from SCI or from (e) V2X message, or whether they are directly detected based on the capability indication or deduced from the supported (e) V2X services, or the like. The predetermined percentage may be set in the UE, or may be configured by the network and informed to the UE through suitable ways such as via SIB or dedicated signaling.

As an example, the predetermined percentage may be set as a high value. In this way, backward compatibility can be ensured. As another example, the predetermined percentage may be set as a low value. In this way, simple forward compatibility can be achieved.

To sum up, if some or all of the detected capability indications indicate that certain sidelink capabilities are supported, the UE 1 may select to adopt some or all of those detected sidelink capabilities which it also supports when performing sidelink transmission. In this way, UEs with different sidelink capability sets can be enabled to properly perform sidelink communication with each other. Thereby, the benefit of the new sidelink feature (s) can be exploited whenever possible and desired, while the communication between the UEs with different sidelink capability sets is not undesirably affected.

Optionally, in case the position related information is acquired from step 202’c, the capability subset may be determined based further on the acquired position related information. This determination is similar to the above determination based merely on the capability related information. The difference between them lies in that the one or more UEs 2 in the above determination are replaced with at least one UE 2 whose position related information meets a predetermined condition.

In case the position related information is S-RSRP, the predetermined condition may be that the S-RSRP is above a predetermined threshold. In case the position related information is a position indication, the predetermined condition may be that the UE 2’s position is within a predetermined distance range of the UE 1.

The predetermined threshold or the predetermined distance range may be service specific. That is, different services may have different predetermined thresholds or predetermined distance ranges. The predetermined threshold or the predetermined distance range may be set in the UE, or may be configured by the network and informed to the UE through suitable ways such as via SIB or dedicated signaling.

In addition to

steps

202c, 204 and 206, the UE 1 may optionally transmit its capability related information, as the UE 2 does in step 202a. As an option, before step 202c is performed for the first time (that is, the UE 1 does not know anything about its surrounding UEs’sidelink capability sets) , the UE 1 may transmit its capability related information with a legacy sidelink format. For example, only legacy L1/L2 format may be used for SCI and/or (e) V2X message, if the UE 1 knows nothing about the sidelink capability of the surrounding UE (s) . After step 206 is performed, the UE 1 may transmit its capability related information with a sidelink format compatible with the determined capability subset. For example, short TTI may be used if some or all of the surrounding UE (s) support short TTI, while new radio access technology (RAT) may be adopted if some or all of the surrounding UE (s) support that.

In other words, if the UE 1 does not know whether certain sidelink capabilities are supported by the surrounding UEs, it transmits the sidelink capability indication in a sidelink format without using those sidelink capabilities. For example, the UE 1 may just transmit the capability indication by using the reserved bits in SCI and/or (e) V2X message (header or body) , and using the L1/L2 format corresponding to compatible capabilities. In this way, the L1/L2 format and/or the content of the indication may be adapted depending on the knowledge of sidelink capabilities supported by the surrounding UEs.

As another option, this transmission step, the obtaining step 202c, the determining step 204 and the determining step 206 may be performed sequentially and iteratively. In each iteration, a portion of capability indications may be transmitted with a sidelink format compatible with the capabilities indicated by the portion. The portion of capability indications transmitted in one iteration may be a superset of the portion in previous iteration (s) .

For example, initially (e.g. for the first iteration) , only a first portion of supported capabilities may be transmitted using L1/L2 format compatible with the first portion of capabilities. By this first portion, the UE 1 may just indicate part of its supported sidelink capabilities, or may just indicate whether it is a legacy Release or a new Release UE. Then, steps 202c, 204 and 206 are performed for this first iteration.

Later on (e.g. for the subsequent iteration) , the UE 1 may transmit more supported capabilities with compatible L1/L2 format, for example, if the determination result of step 206 in the first iteration shows that some or all of the surrounding UEs are new Release UEs, which can understand the new format of SCI/ (e) V2x message (header or body) that contains the sidelink capability indication. Likewise, steps 202c, 204 and 206 are performed for this subsequent iteration. In this way, the capability subset for use in sidelink transmission can be iteratively determined.

Optionally, a legacy UE may not transmit its capability related information such as capability indication and/or the presence bit/Release indication bit. Thus, a UE can be deemed as a legacy UE that does not support any new sidelink capability, if the sidelink capability indication or the indication presence bit/Release indication bit is not transmitted, and no (e) V2X message indicates that relevant new (e) V2X services are supported.

FIG. 3 is a diagram illustrating a second solution of the disclosure. There are shown three entities, UE 1, UE 2 and network (NW) , in this solution. The NW may be represented by a base station serving the UE 1 and the UE 2. This solution is similar to the first solution except that the capability related information and optionally the position related information are transmitted over Uu instead of sidelink. Thus, only this difference is described below for brevity.

Specifically, at step 302a, the UE 2 transmits its capability related information over Uu uplink (UL) . Then, at step 302b, the NW forwards the UE 2’s capability related information to the UE 1. Thus, at step 302c, the UE 1 receives the UE 2’s capability related information over Uu downlink (DL) .

The capability related information may be a capability indication or a service indication as described above. It may be transmitted in the body of a message such as a general or special (e) V2X message. It should be noted that the NW redistributes the message to the other UEs in the system although only UE 1 is shown as the recipient.

Optionally, at step 302’a, the UE 2 transmits its position related information over Uu UL. Then, at step 302’b, the NW forwards the UE 2’s position related information to the UE 1. Thus, at step 302’c, the UE 1 receives the UE 2’s position related information over Uu DL. The position related information may be a position indication as described above. It may be transmitted in the body of a message such as a general or special (e) V2X message.

FIG. 4 is a diagram illustrating a third solution of the disclosure. As shown, this solution is a combination of the first and second solutions. Specifically, at step 402, the UE 2 transmits its capability related information to the UE 1. This may be done over sidelink, or Uu, or a combination thereof. Optionally, at step 402’, the UE 2 transmits its position related information to the UE 1. This may also be done over sidelink, or Uu, or a combination thereof. Then, steps 404 and 406 are performed to determine the capability subset. This may be done as described above with respect to steps 204 and 206, and thus their details are omitted here for brevity.

In the first to third solutions above, it should be noted that how to decode SCI and/or (e) V2X message is based on L1/L2 format, resource allocation, modulation and coding scheme (MCS) and so on, but not capability indication. For instance, although a UE supports short TTI, it may still temporarily transmit with normal TTI. From SCI, a short TTI capable UE could know whether short or normal TTI is used in certain frequency/time resource (s) , and adopt the appropriate decoding scheme in that resource (s) .

FIG. 5 is a diagram illustrating a fourth solution of the disclosure. The differences between this solution and the first to third solutions mainly lie in that the determination of the capability subset is performed by the NW but not the UE 1. In this solution, the NW may be a base station or a central node, as described later.

At step 502a, the UE 2 transmits its capability related information to the network over Uu UL. At step 502b, the UE 1 transmits its capability related information to the network over Uu UL.

Steps

502a and 502c may be performed one after another or simultaneously.

The capability related information may be a capability indication or a service indication as described above. It may be transmitted via Uu UL in various ways. As a first option, a capability indication may be transmitted in radio resource control (RRC) signaling. As a second option, a capability indication may be transmitted in the body of a message such as a general or special (e) V2X message. As a third option, a service indication may be transmitted in the body of a message such as a general or special (e) V2X message. The above first to third options may be used in any combination.

Then, at step 502c, the NW receives the capability related information. In this way, the NW can collect the capability related information of the UE 1 and the one or more UEs 2. In case the UE 1 and the one or more UEs 2 are located in a same cell, the NW can be represented by the base station of this cell. In this case, the base station collects the capability related information directly from these UEs.

In case the UE 1 and the one or more UEs 2 are located in multiple neighboring cells and belong to the same network operator, the NW can be represented by the base station serving the UE 1. In this case, for some UEs 2, the base station collects their capability related information directly. For the other UEs 2, the base station collects their capability related information from neighboring base stations.

In case the UE 1 and the one or more UEs 2 belong to different network operators, the NW can be represented as a central node such as a V2X server. In this case, the central node collects these UEs’capability related information from the multiple neighboring base stations. The central node could also be applied in the case where the UE 1 and the one or more UEs 2 belong to the same network operator.

Optionally, at step 502’a, the UE 2 transmits its position related information to the network over Uu UL. At step 502’b, the UE 1 transmits its position related information to the network over Uu UL. Steps 502’a and 502’c may be performed one after another or simultaneously. Further, steps 502’a and 502a may be performed one after another or simultaneously. The position related information may be a position indication as described above. It may be transmitted in the body of a message such as a general or special (e) V2X message.

Then, at step 502’c, the network receives the position related information. In this way, the NW can collect the position related information of the UE 1 and the one or more UEs 2. Similar to step 502c, the NW can be represented by a base station or a central node.

Then, at step 504, the NW determines sidelink capability sets of the UE 1 and the one or more UEs 2 from the obtained capability related information. Then, at step 506, the NW determines, from the UE 1’s sidelink capability set, a capability subset for use in its sidelink transmission to the UE 2, based on the determined sidelink capability sets of the one or more second terminal devices. Optionally, the determination may be performed based further on the position related information acquired from step 502’c. Steps 504 and 506 are similar to steps 204 and 206 except that the determination is made by the NW instead of the UE 1. Thus, their details are omitted here for brevity.

Then, at step 508a, the network informs the UE 1 of the determined capability subset over Uu DL. Correspondingly, at step 508b, the UE 1 receives the determined capability subset over Uu DL. In this way, the UE can be relieved from the burden of making the determination.

FIG. 6 is a flowchart illustrating a method at terminal device side according to an embodiment of the disclosure. At step 602, a first terminal device with a first sidelink capability set obtains capability related information of one or more second terminal devices. This step may be performed as described above with respect to

steps

202c, 302c and 402.

Then, at step 604, the first terminal device determines sidelink capability sets of the one or more second terminal devices from the obtained capability related information. This step may be performed as described above with respect to

steps

204, 304 and 404. Then, at step 606, the first terminal device determines, from the first sidelink capability set, a capability subset for use in sidelink transmission to a second terminal device, based at least on the determined sidelink capability sets. This step may be performed as described above with respect to steps 206, 306 and 406.

FIG. 7 is a flowchart illustrating a method at terminal device side according to another embodiment of the disclosure. At step 702, a first terminal device with a first sidelink capability set obtains capability related information of one or more second terminal devices. This step is the same as step 602. At step 703, the first terminal device acquires position related information of the one or more second terminal devices. This step may be performed as described above with respect to steps 202’c, 302’c and 402’.

Then, at step 704, the first terminal device determines sidelink capability sets of the one or more second terminal devices from the obtained capability related information. This step is the same as step 604. Then, at step 706, the first terminal device determines, from the first sidelink capability set, a capability subset for use in sidelink transmission to a second terminal device, based on the determined sidelink capability sets and the acquired position related information. This step may be performed as described above with respect to step 206, 306 and 406.

FIGs. 8A and 8B are flowcharts each illustrating a method at terminal device side according to an embodiment of the disclosure. In the method of FIG. 8A, at step 810-1, the first terminal device transmits its capability related information with a legacy sidelink format. Then, steps 602-606 or 702-706 are performed. As a result, the capability subset for use in sidelink transmission is determined. Then, at step 810-2, the first terminal device transmits its capability related information with a sidelink format compatible with the determined capability subset. This method has been described above with reference to FIG. 2 and its details are omitted here for brevity.

In the method of FIG. 8B, at step 810-3, the first terminal device transmits a first portion of its capability indications with a sidelink format compatible with the capabilities indicated by the first portion. As described above, the first portion may just indicate part of the supported sidelink capabilities, or may just indicate whether the first terminal device is a legacy Release or a new Release terminal device. Then, steps 602-606 or 702-706 are performed. For example, the determination result of

step

606 or 706 may indicate that some or all of the surrounding terminal devices are new Release terminal devices.

Then, at step 810-4, the first terminal device transmits a second portion of its capability indications with a sidelink format compatible with the capabilities indicated by the second portion. As described above, the second portion may indicate more supported capabilities. Additionally, the capabilities indicated by the second portion may include some or all of those capabilities indicated by the first portion. That is, the second portion is a superset of the first portion. Then, steps 602-606 or 702-706 are performed. In this way, the capability subset for use in sidelink transmission can be iteratively determined. It should be noted that three or more iterations may be carried out although only two iterations are shown in FIG. 8B.

FIG. 9 is a flowchart illustrating a method at network side according to an embodiment of the disclosure. At step 902, a network device, which may be a base station (e.g. an eNB or a gNB) or a central node (e.g. a V2X server) , obtains capability related information of a plurality of terminal devices. The plurality of terminal devices comprises a first terminal device and one or more second terminal devices. Step 902 may performed as described above with respect to step 502c.

At step 904, the network device determines sidelink capability sets of the plurality of terminal devices from the obtained capability related information. This step may be performed as described above with respect to step 504.

At step 906, the network device determines, from a first sidelink capability set of the first terminal device, a capability subset for use in sidelink transmission from the first terminal device to a second terminal device, based at least on the determined sidelink capability sets of the one or more second terminal devices. This step may be performed as described above with respect to step 506. Then, at step 908, the network device informs the first terminal device of the determined capability subset. This step may be performed as described above with respect to step 508a.

FIG. 10 is a flowchart illustrating a method at network side according to another embodiment of the disclosure. At step 1002, a network device obtains capability related information of a plurality of terminal devices. The plurality of terminal devices comprises a first terminal device and one or more second terminal devices. Step 1002 is the same as step 902.

At step 1003, the network device acquires position related information of the plurality of terminal devices. This step may be performed as described above with respect to step 502’c.

At step 1004, the network device determines sidelink capability sets of the plurality of terminal devices from the obtained capability related information. Then, at step 1006, the network device determines, from a first sidelink capability set of the first terminal device, a capability subset for use in sidelink transmission from the first terminal device to a second terminal device, based at least on the determined sidelink capability sets and the acquired position related information of the one or more second terminal devices. This step may be performed as described above with respect to step 506. Then, at step 1008, the network device informs the first terminal device of the determined capability subset. This step is the same as step 908.

FIG. 11 is a block diagram illustrating a terminal device according to an embodiment of the disclosure. As shown, the terminal device 1100 comprises a processor 1102 and a memory 1104. Although only one processor and only one memory are shown in FIG. 11, the number of each of them may be more than one. The memory 1104 contains instructions which may be executed by the processor 1102 to cause the terminal device 1100 to perform the method steps described above with reference to FIGs. 6 to 8. Besides, the other configurations of the terminal device 1100 may be well known to those skilled in the art, and thus the detailed description thereof is omitted here.

FIG. 12 is a block diagram illustrating a network device according to an embodiment of the disclosure. As shown, the network device 1200 comprises a processor 1202 and a memory 1204. Although only one processor and only one memory are shown in FIG. 12, the number of each of them may be more than one. The memory 1204 contains instructions which may be executed by the processor 1202 to cause the network device 1200 to perform the method steps described above with reference to FIGs. 9 and 10. Besides, the other configurations of the network device 1200 may be well known to those skilled in the art, and thus the detailed description thereof is omitted here.

FIG. 13 is a block diagram illustrating a terminal device according to another embodiment of the disclosure. As shown, the terminal device 1300 may comprise an obtaining module 1302, a first determination module 1304 and a second determination module 1306. The obtaining module 1302 is configured to obtain capability related information of one or more second terminal devices. The obtaining module 1302 may be implemented as described above with respect to step 602. The first determination module 1304 is configured to determine sidelink capability sets of the one or more second terminal devices from the obtained capability related information. The first determination module 1304 may be implemented as described above with respect to step 604. The second determination module 1306 is configured to determine, from a first sidelink capability set of the first terminal device, a capability subset for use in sidelink transmission to a second terminal device, based at least on the determined sidelink capability sets. The second determination module 1306 may be implemented as described above with respect to step 606. Optionally, the terminal device 1300 may comprise an acquisition module configured to acquire position related information of the one or more second terminal devices. The second determination module may be configured to determine the capability subset based further on the acquired position related information. The modules described above may be implemented by hardware, or software, or a combination of both.

FIG. 14 is a block diagram illustrating a network device according to another embodiment of the disclosure. As shown, the network device 1400 may comprise an obtaining module 1402, a first determination module 1404, a second determination module 1406 and an informing module 1408. The obtaining module 1402 is configured to obtain capability related information of a plurality of terminal devices. The plurality of terminal devices comprises a first terminal device and one or more second terminal devices. The obtaining module 1402 may be implemented as described above with respect to step 902. The first determination 1404 module is configured to determine sidelink capability sets of the plurality of terminal devices from the obtained capability related information. The first determination 1404 may be implemented as described above with respect to step 904. The second determination module 1406 is configured to determine, from a first sidelink capability set of the first terminal device, a capability subset for use in sidelink transmission from the first terminal device to a second terminal device, based at least on the determined sidelink capability sets of the one or more second terminal devices. The second determination module 1406 may be implemented as described above with respect to step 906. The informing module 1408 is configured to inform the first terminal device of the determined capability subset. The informing module 1408 may be implemented as described above with respect to step 908. Optionally, the network device may comprise an acquisition module configured to acquire position related information of the plurality of terminal devices. The second determination module may be configured to determine the capability subset based further on the acquired position related information. The modules described above may be implemented by hardware, or software, or a combination of both.

In general, the various exemplary embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the disclosure is not limited thereto. While various aspects of the exemplary embodiments of this disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

As such, it should be appreciated that at least some aspects of the exemplary embodiments of the disclosure may be practiced in various components such as integrated circuit chips and modules. It should thus be appreciated that the exemplary embodiments of this disclosure may be realized in an apparatus that is embodied as an integrated circuit, where the integrated circuit may comprise circuitry (as well as possibly firmware) for embodying at least one or more of a data processor, a digital signal processor, baseband circuitry and radio frequency circuitry that are configurable so as to operate in accordance with the exemplary embodiments of this disclosure.

It should be appreciated that at least some aspects of the exemplary embodiments of the disclosure may be embodied in computer-executable instructions, such as in one or more program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types when executed by a processor in a computer or other device. The computer executable instructions may be stored on a computer readable medium such as a hard disk, optical disk, removable storage media, solid state memory, RAM, etc. As will be appreciated by one of skill in the art, the function of the program modules may be combined or distributed as desired in various embodiments. In addition, the function may be embodied in whole or in part in firmware or hardware equivalents such as integrated circuits, field programmable gate arrays (FPGA) , and the like.

References in the present disclosure to “one embodiment” , “an embodiment” and so on, indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It should be understood that, although the terms “first” , “second” and so on 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 the disclosure. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed terms.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present disclosure. 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. It will be further understood that the terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” , when used herein, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof.

The present disclosure includes any novel feature or combination of features disclosed herein either explicitly or any generalization thereof. Various modifications and adaptations to the foregoing exemplary embodiments of this disclosure may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings. However, any and all modifications will still fall within the scope of the non-Limiting and exemplary embodiments of this disclosure.

Claims

A method implemented at a first terminal device with a first sidelink capability set, comprising:

obtaining (602) capability related information of one or more second terminal devices;

determining (604) sidelink capability sets of the one or more second terminal devices from the obtained capability related information; and

determining (606) , from the first sidelink capability set, a capability subset for use in sidelink transmission to a second terminal device, based at least on the determined sidelink capability sets.
The method according to claim 1, wherein determining (606) the capability subset comprises:

when a capability in the first sidelink capability set is included in at least a predetermined percentage of the sidelink capability sets of the one or more second terminal devices, determining the capability as a member of the capability subset.
The method according to claim 1 or 2, wherein the capability related information comprises a capability indication that indicates a sidelink capability set of a second terminal device; and/or

wherein the capability related information comprises a service indication that indicates a service set suppored by a second terminal device, and

determining (604) the sidelink capability sets of the one or more second terminal devices comprises deducing the sidelink capability sets of the one or more second terminal devices from the service indications of the one or more second terminal devices.
The method according to claim 1 or 3, further comprising:

acquiring (703) position related information of the one or more second terminal devices; and

wherein determining (606) the capability subset is performed based further on the acquired position related information.
The method according to claim 4, wherein determining (606) the capability subset comprises:

selecting, from the one or more second terminal devices, at least one second terminal device whose position related information meets a predetermined condition; and

when a capability in the first sidelink capability set is included in at least a predetermined percentage of the sidelink capability set of the selected at least one second terminal device, determining the capability as a member of the capability subset.
The method according to claim 4 or 5, wherein the position related information comprises a sidelink reference signal received power, S-RSRP, from a second terminal device, and the predetermined condition is that the S-RSRP is above a predetermined threshold; and/or

wherein the position related information comprises a position indication that indicates a position of a second terminal device, and the predetermined condition is that the position of the second terminal device is within a predetermined distance range of the first terminal device.
The method according to any of claims 2 to 6, wherein the predetermined percentage is set in the first terminal device, or is signaled from a base station serving the first terminal device; and

wherein the predetermined percentage is set depending on at least one of:

the service to which the predetermined percentage is to apply; and

the way by which the sidelink capability sets of the one or more second terminal devices are determined.
The method according to claim 6, wherein the predetermined threshold or the predetermined distance range is set in the first terminal device, or is signaled from a base station serving the first terminal device; and

wherein the predetermined threshold or the predetermined distance range is set depending on the service to which the predetermined threshold or the predetermined distance range is to apply.
The method according to any of claims 3 to 8, wherein the obtaining (602) comprises at least one of:

detecting a capability indication from sidelink control information, SCI, over sidelink;

detecting a capability indication from a message header over sidelink;

detecting a capability indication from a message body over sidelink or downlink;

detecting a service indication from a message body over sidelink or downlink; and

retrieving capability related information of a second terminal device from a memory of the first terminal device based on an identity, ID, of the second terminal device, wherein previously obtained capability related information and ID of the second terminal device are stored in association in the memory of the first terminal device.
The method according to any of claims 6 to 9, wherein the acquiring (703) comprises at least one of:

measuring an S-RSRP; and

detecting, over sidelink or downlink, a position indication from a message body which is the same or different than that for the capability related information.
The method according to any of claims 1 to 10, further comprising:

transmitting (810-1, 810-2, 810-3, 810-4) capability related information of the first terminal device.
The method according to claim 11, wherein before the obtaining (602) , the transmitting (810-1) is performed with a legacy sidelink format; and

wherein after determining (606) the capability subset, the transmitting (810-2) is performed with a sidelink format compatible with the determined capability subset.
The method according to claim 11, wherein the transmitting (810-3, 810-4) , obtaining (602) , determining (604) the sidelink capability sets and determining (606) the capability subset are performed sequentially and iteratively;

wherein in each iteration, a portion of capability indications is transmitted with a sidelink format compatible with the capabilities indicated by the portion; and

wherein the portion of capability indications in one iteration is a superset of the portion in previous iteration (s) .
The method according to claim 11, wherein the transmitting (810-1, 810-2, 810-3, 810-4) is performed periodically or in response to a trigger event;

wherein the periodicity, or the periodicity configuration rule, or the trigger event is predefined in the first terminal device, or is signaled from a base station serving the first terminal device; and

wherein the periodicity is set depending on at least one of a speed and a carrier frequency of the first terminal device, and the trigger event is set depending on at least one of a speed and a position of the first terminal device.
A method implemented at a network device, comprising:

obtaining (902) capability related information of a plurality of terminal devices, wherein the plurality of terminal devices comprises a first terminal device and one or more second terminal devices;

determining (904) sidelink capability sets of the plurality of terminal devices from the obtained capability related information;

determining (906) , from a first sidelink capability set of the first terminal device, a capability subset for use in sidelink transmission from the first terminal device to a second terminal device, based at least on the determined sidelink capability sets of the one or more second terminal devices; and

informing (908) the first terminal device of the determined capability subset.
The method according to claim 15, wherein determining (906) the capability subset comprises:

when a capability in the first sidelink capability set is included in at least a predetermined percentage of the sidelink capability sets of the one or more second terminal devices, determining the capability as a member of the capability subset.
The method according to claim 15 or 16, wherein the capability related information comprises a capability indication that indicates a sidelink capability set of a terminal device; and/or

wherein the capability related information comprises a service indication that indicates a service set suppored by a terminal device, and

determining (904) the sidelink capability sets of the plurality of terminal devices comprises deducing the sidelink capability sets of the plurality of terminal devices from the service indications of the plurality of terminal devices.
The method according to claim 15 or 17, further comprising:

acquiring (1003) position related information of the plurality of terminal devices; and

wherein determining (906) the capability subset is performed based further on the acquired position related information.
The method according to claim 18, wherein determining (906) the capability subset comprises:

selecting, from the one or more second terminal devices, at least one second terminal device whose position related information meets a predetermined condition; and

when a capability in the first sidelink capability set is included in at least a predetermined percentage of the sidelink capability set of the selected at least one second terminal device, determining the capability as a member of the capability subset.
The method according to claim 18 or 19, wherein the position related information comprises a position indication that indicates a position of a terminal device, and the predetermined condition is that the position of the second terminal device is within a predetermined distance range of the first terminal device.
The method according to any of claims 17 to 20, wherein the obtaining (902) comprises at least one of:

detecting a capability indication from a message body over uplink;

detecting a service indication from a message body over uplink; and

detecting a capability indication from radio resource control (RRC) signaling over uplink.
The method according to claim 20 or 21, wherein the acquiring (1003) comprises detecting, over uplink, a position indication from a message body which is the same or different than that for the capability related information.
The method according to any of claims 15 to 22, wherein the network device is a base station serving the first terminal device; and

wherein the obtaining (902) comprises at least one of:

receiving capability related information from a second terminal device; and

receiving, from a neighboring base station, capability related information of a second terminal device.
The method according to any of claims 15 to 22, wherein the network device is a central server; and

wherein capability related information of the plurality of terminal devices is obtained from a plurality of base stations serving the plurality of terminal devices.
A first terminal device (1100) , comprising:

at least one processor (1102) ; and

at least one memory (1104) , the at least one memory (1104) containing instructions executable by the at least one processor (1102) , whereby the first terminal device (1100) is operative to:

obtain capability related information of one or more second terminal devices;

determine sidelink capability sets of the one or more second terminal devices from the obtained capability related information; and

determine, from a first sidelink capability set of the first terminal device, a capability subset for use in sidelink transmission to a second terminal device, based at least on the determined sidelink capability sets.
The first terminal device (1100) according to claim 25, wherein the first terminal device (1100) is operative to perform the method of any of claims 2 to 14.
A network device (1200) , comprising:

at least one processor (1202) ; and

at least one memory (1204) , the at least one memory (1204) containing instructions executable by the at least one processor (1202) , whereby the network device (1200) is operative to:

obtain capability related information of a plurality of terminal devices, wherein the plurality of terminal devices comprises a first terminal device and one or more second terminal devices;

determine sidelink capability sets of the plurality of terminal devices from the obtained capability related information;

determine, from a first sidelink capability set of the first terminal device, a capability subset for use in sidelink transmission from the first terminal device to a second terminal device, based at least on the determined sidelink capability sets of the one or more second terminal devices; and

inform the first terminal device of the determined capability subset.
The network device (1200) according to claim 27, wherein the network device (1200) is operative to perform the method of any of claims 16 to 24.
A computer readable storage medium comprising instructions which when executed by at least one processor, cause the at least one processor to perform the method according to any of claims 1 to 14.
A computer readable storage medium comprising instructions which when executed by at least one processor, cause the at least one processor to perform the method according to any of claims 15 to 24.