WO2022061736A1

WO2022061736A1 - Methods and apparatuses for inter-ue coordination for a nr sidelink

Info

Publication number: WO2022061736A1
Application number: PCT/CN2020/117822
Authority: WO
Inventors: Zhennian SUN; Xiaodong Yu; Haipeng Lei; Haiming Wang
Original assignee: Lenovo (Beijing) Limited
Priority date: 2020-09-25
Filing date: 2020-09-25
Publication date: 2022-03-31

Abstract

Embodiments of the present disclosure relate to methods and apparatuses for inter-UE (user equipment) coordination for new radio (NR) sidelink under 3GPP (3rd Generation Partnership Project) 5G system. According to an embodiment of the present disclosure, a method includes: transmitting, to another UE, information regarding one or more candidate receivers; receiving, from the abovementioned another UE, signaling indicating a set of resources in at least one domain of time and frequency domains, wherein the set of resources corresponds to one candidate receiver or a subset of candidate receivers within the one or more candidate receivers; performing a resource selection procedure by taking the set of resources into account, to select a transmission resource; and transmitting, to the one candidate receiver, a data transmission on the selected transmission resource.

Description

METHODS AND APPARATUSES FOR INTER-UE COORDINATION FOR A NR SIDELINK

TECHNICAL FIELD

Embodiments of the present application are related to wireless communication technology, and more particularly, related to methods and apparatuses for inter-UE (user equipment) coordination for a new radio (NR) sidelink.

BACKGROUND

Vehicle to everything (V2X) has been introduced into 3GPP (3rd Generation Partnership Project) 5G wireless communication technology. In terms of a channel structure of V2X communication, a direct link between two UEs is called a sidelink. A sidelink is a long-term evolution (LTE) feature introduced in 3GPP Release 12, and enables a direct communication between proximal UEs, and data does not need to go through a base station (BS) or a core network.

3GPP 5G and/or NR networks are expected to increase network throughput, coverage, and robustness and reduce latency and power consumption. With the development of 3GPP 5G and/or NR networks, various aspects need to be studied and developed to perfect the 5G and/or NR technology.

SUMMARY

Some embodiments of the present application provide a method, which may be performed by a user equipment (UE) . The method includes: transmitting, to another UE, information regarding one or more candidate receivers; receiving, from the abovementioned another UE, signaling indicating a set of resources in at least one domain of time and frequency domains, wherein the set of resources corresponds to one candidate receiver or a subset of candidate receivers within the one or more candidate receivers; performing a resource selection procedure by taking the set of resources into account, to select a transmission resource; and transmitting, to the one candidate receiver or the subset of candidate receivers, a data transmission on the selected transmission resource. In an embodiment, the subset of candidate receivers corresponds to a sidelink broadcast session and a sidelink groupcast session.

Some embodiments of the present application provide a method, which may be performed by a UE. The method includes: receiving, from another UE, information regarding one or more candidate receivers; and transmitting, to the abovementioned another UE, signaling indicating a set of resources in at least one domain of time and frequency domains. The set of resources corresponds to one candidate receiver or a subset of candidate receivers within the one or more candidate receivers, and the set of resources is taken into account during a resource selection procedure, to select a transmission resource for a data transmission to the one candidate receiver or the subset of candidate receivers. In an embodiment, the subset of candidate receivers corresponds to a sidelink broadcast session and a sidelink groupcast session.

Some embodiments of the present application provide an apparatus. The apparatus includes: a non-transitory computer-readable medium having stored thereon computer-executable instructions, a receiving circuitry; a transmitting circuitry; and a processor coupled to the non-transitory computer-readable medium, the receiving circuitry and the transmitting circuitry, wherein the computer-executable instructions cause the processor to implement any of the abovementioned method performed by a UE.

The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which advantages and features of the present application can be obtained, a description of the present application is rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. These drawings depict only exemplary embodiments of the present application and are not therefore intended to limit the scope of the present application.

FIG. 1 illustrates an exemplary V2X communication system in accordance with some embodiments of the present application;

FIG. 2 illustrates an exemplary flow chart of a method for performing a resource selection procedure according to some embodiments of the present application;

FIG. 3 illustrates a further exemplary flow chart of a method for indicating a set of resources according to some embodiments of the present application;

FIG. 4 illustrates an exemplary diagram of indicating a set of resources according to some embodiments of the present application; and

FIG. 5 illustrates an exemplary block diagram of an apparatus according to some embodiments of the present application.

DETAILED DESCRIPTION

The detailed description of the appended drawings is intended as a description of preferred embodiments of the present application and is not intended to represent the only form in which the present application may be practiced. It should be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present application.

Reference will now be made in detail to some embodiments of the present application, examples of which are illustrated in the accompanying drawings. To facilitate understanding, embodiments are provided under specific network architecture and new service scenarios, such as 3GPP 5G, 3GPP LTE Release 8, B5G, 6G, and so on. It is contemplated that along with developments of network architectures and new service scenarios, all embodiments in the present application are also applicable to similar technical problems; and moreover, the terminologies recited in the present application may change, which should not affect the principle of the present application.

In a V2X communication system, a transmission UE may also be named as a transmitting UE, a Tx UE, a sidelink Tx UE, a sidelink transmission UE, or the like. A reception UE may also be named as a receiving UE, a Rx UE, a sidelink Rx UE, a sidelink reception UE, or the like.

FIG. 1 illustrates an exemplary V2X communication system in accordance with some embodiments of the present application.

As shown in FIG. 1, a wireless communication system 100 includes at least five user equipments (UEs) , including one coordination UE 101, one transmitting UE 102 (i.e., Tx UE 102 as shown in FIG. 1) , and three receiving UEs 103 (i.e., Rx UE 103a, Rx UE 103b, Rx UE 103c, and Rx UE 103d as shown in FIG. 1) for illustrative purpose. Although a specific number of UEs 101, 102, and 103 are depicted in FIG. 1, it is contemplated that any number of UEs 101, 102, and 103 may be included in the wireless communication system 100.

The V2X transmission implemented in the wireless communication system 100 of the embodiments of FIG. 1 includes unicast transmission, groupcast transmission, and broadcast transmission. For example, each of Rx UE 103c and Rx UE 103d represents Rx UEs for unicast transmission. Rx UE 103a and Rx UE 103b may form group#1 as shown in FIG. 1. The group#1 has a destination identity (ID) . The group#1 may correspond to a sidelink groupcast session for groupcast transmission. Tx UE 102 may transmit data to Rx UE 103a and Rx UE 103b in group#1 through a sidelink groupcast session. The group#1 may correspond to a sidelink broadcast session for broadcast transmission. Tx UE 102 may transmit data to Rx UE 103a and Rx UE 103b in group#1 through a sidelink broadcast session.

Each UE in FIG. 1 may include computing devices, such as desktop computers, laptop computers, personal digital assistants (PDAs) , tablet computers, smart televisions (e.g., televisions connected to the Internet) , set-top boxes, game consoles, security systems (including security cameras) , vehicle on-board computers, network devices (e.g., routers, switches, and modems) , or the like. According to some embodiments of the present application, a UE in FIG. 1 may include a portable wireless communication device, a smart phone, a cellular telephone, a flip phone, a device having a subscriber identity module, a personal computer, a selective call receiver, or any other device that is capable of sending and receiving communication signals on a wireless network.

In some embodiments of the present application, a UE in FIG. 1 is a pedestrian UE (P-UE or PUE) or a cyclist UE. In some embodiments of the present application, a UE in FIG. 1 includes wearable devices, such as smart watches, fitness bands, optical head-mounted displays, or the like. Moreover, a UE in FIG. 1 may be referred to as a subscriber unit, a mobile, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, a user terminal, or a device, or described using other terminology used in the art. A UE in FIG. 1 may communicate directly with a base station (BS) via LTE or NR Uu interface.

In some embodiments of the present application, each UE in FIG. 1 may be deployed an IoT application, an enhanced mobile broadband (eMBB) application and/or an ultra-reliable and low latency communication (URLLC) application. For instance, Tx UE 102 may implement an IoT application and may be named as an IoT UE, while Rx UE 103a may implement an eMBB application and/or a URLLC application and may be named as an eMBB UE, an URLLC UE, or an eMBB/URLLC UE. It is contemplated that the specific type of application (s) deployed in the UE in FIG. 1 may be varied and not limited.

According to some embodiments of FIG. 1, a UE may exchange V2X messages with another UE (s) through a sidelink, for example, PC5 interface as defined in 3GPP TS 23.303. The UE may transmit information or data to another UE (s) within the V2X communication system, through sidelink unicast, sidelink groupcast, or sidelink broadcast. For instance, Tx UE 102 transmits data to Rx UE 103a in a sidelink unicast session. Tx UE 102 may transmit data to Rx UE 103a, Rx UE 103b, Rx UE 103c, and Rx UE 103d and other UEs (not shown in FIG. 1) in a groupcast group (not shown in FIG. 1) by a sidelink groupcast transmission session. Also, Tx UE 102 may transmit data to Rx UE 103a, Rx UE 103b, Rx UE 103c, and Rx UE 103d and other UEs (not shown in FIG. 1) by a sidelink broadcast transmission session.

The wireless communication system 100 may be compatible with any type of network that is capable of sending and receiving wireless communication signals. For example, the wireless communication system 100 is compatible with a wireless communication network, a cellular telephone network, a Time Division Multiple Access (TDMA) -based network, a Code Division Multiple Access (CDMA) -based network, an Orthogonal Frequency Division Multiple Access (OFDMA) -based network, an LTE network, a 3GPP-based network, a 3GPP 5G network, a satellite communications network, a high altitude platform network, and/or other communications networks.

In some embodiments of the present application, the wireless communication system 100 is compatible with the 5G NR of the 3GPP protocol, wherein BS (s) (not shown in FIG. 1) transmit data using an OFDM modulation scheme on the downlink (DL) and the UE (s) in FIG. 1 transmit data on the uplink (UL) using a Discrete Fourier Transform-Spread-Orthogonal Frequency Division Multiplexing (DFT-S-OFDM) or cyclic prefix-OFDM (CP-OFDM) scheme. More generally, however, the wireless communication system 100 may implement some other open or proprietary communication protocols, for example, WiMAX, among other protocols.

Currently, two sidelink resource allocation modes are supported, i.e., Mode 1 and Mode 2. In Mode 1, the sidelink resource in time and frequency domains allocation is provided by a network or a BS. In Mode 2, a UE decides the SL transmission resources in time and frequency domains in a resource pool.

According to agreements of 3GPP standard documents, in a 3GPP 5G NR sidelink system or the like, inter-UE coordination can be used to enhance the reliability of a sidelink transmission. The definition of inter-UE coordination is that a set of resources is determined at a coordination UE (e.g., coordination UE 101 as illustrated and shown in FIG. 1) . This set of resources may be sent to a Tx UE in Mode 2 (e.g., Tx UE 102 as illustrated and shown in FIG. 1) , and the Tx UE in Mode 2 may take this set of resources into account during a resource selection procedure for its own transmission. At the side of the Tx UE in Mode 2, there may be multiple sessions or multiple transmissions towards different Rx UE (s) or different destinations. When the set of resources is sent to the Tx UE in Mode 2, this Tx UE should know that the set of resources is targeted for which session, which Rx UE (s) , or which destination.

Referring back to FIG. 1, Tx UE 102 may have multiple sessions to be transmitted to different Rx UEs (e.g., Rx UE 103a, Rx UE 103b, Rx UE 103c, or Rx UE 103d) . For different Rx UEs, interference conditions may be different. Thus, the set of resources transmitted by coordination UE 101 may be only suitable for a certain Rx UE (e.g., one of Rx UE 103a, Rx UE 103b, Rx UE 103c, and Rx UE 103d) . Tx UE 102 should understand for which Rx UE the set of resources is targeted. In particular, in step 1 as shown in FIG. 1, Tx UE 102 transmits trigger information or coordination information to coordination UE 101. In step 2 as shown in FIG. 1, coordination UE 101 transmits a set of resources in time and/or frequency domains to Tx UE 102.

Embodiments of the present application define specific procedures of how to coordinate between different UEs and how to determine a set of resources in time and/or frequency domains and will be specifically described below.

FIG. 2 illustrates an exemplary flow chart of a method for performing a resource selection procedure according to some embodiments of the present application.

The embodiments of FIG. 2 may be performed by a UE (e.g., Tx UE 102 illustrated and shown in FIG. 1 or UE (b) illustrated and shown in FIG. 4) . Although described with respect to a UE, it should be understood that other devices may be configured to perform a method similar to that of FIG. 2.

In the exemplary method 200 as shown in FIG. 2, in operation 201, a UE (e.g., Tx UE 102 illustrated and shown in FIG. 1) transmits, to another UE (e.g., coordination UE 101 illustrated and shown in FIG. 1) , information regarding one or more candidate receivers (e.g., one or more of Rx UE 103a, Rx UE 103b, Rx UE 103c, and Rx UE 103d illustrated and shown in FIG. 1) . A candidate receiver may also be named as an intended receiver, a targeted receiver, a candidate receiving UE, a candidate Rx UE, or the like.

The embodiments of FIG. 2 assume that the UE (e.g., Tx UE 102 illustrated and shown in FIG. 1) works in Mode 2. That is to say, a sidelink resource in the time and/or frequency domains for a sidelink transmission of the UE is decided by the abovementioned another UE. In the embodiments of FIG. 2, the UE functions as a Tx UE, the candidate receiver (s) functions as a Rx UE (s) , and the abovementioned another UE functions as a coordination UE.

According to some embodiments, the information regarding one or more candidate receivers transmitted in operation 201 includes a set of one or more identifiers (IDs) corresponding to the one or more candidate receivers. For instance, the set of one or more IDs includes destination IDs of the one or more candidate receivers.

According to some embodiments, the information regarding one or more candidate receivers transmitted in operation 201 is included in a sidelink buffer status report (BSR) . As specified in 3GPP TS38.321, a sidelink BSR medium access control element (MAC CE) may include the following fields: a destination index, a Logical Channel Group ID (LCG-ID) , and a buffer size.

In one example, the information regarding one or more candidate receivers may include one or more of the following:

(1) An identity (ID) of the candidate receiver (s) for each session, e.g., a destination ID of the candidate receiver (s) for each session.

(2) A priority of each session, e.g., LCG-ID.

(3) A buffer status.

For example, the abovementioned another UE may determine one candidate receiver or a subset of candidate receivers through a logical channel prioritization (LCP) procedure based on a sidelink BSR, which includes the information regarding one or more candidate receivers. A specific example is described in FIG. 4.

According to some embodiments, the information regarding one or more candidate receivers is transmitted or carried by at least one of physical channel information and high layer signaling of the UE (e.g., Tx UE 102 illustrated and shown in FIG. 1) . In particular:

(1) Physical channel. For instance, the information regarding one or more candidate receivers is transmitted in sidelink control information (SCI) , e.g., a 2nd stage SCI. For this case, according to 3GPP Release-16 agreements, the 1st stage SCI will indicate that its corresponding 2nd stage SCI is used to transmit the information of the candidate receiver (s) .

More specifically, one of two reserved values of “2nd -stage SCI format” in SCI format 1-A can be used to transmit the information regarding one or more candidate receivers.

(2) High layer signaling of the UE. For example, the information regarding one or more candidate receivers may be carried in sidelink RRC signaling or a sidelink MAC CE.

Referring back to FIG. 2, in operation 202, the UE receives signaling from the abovementioned another UE. The signaling indicates a set of resources in time and/or frequency domains. The set of resources corresponds to one specific candidate receiver or a subset of candidate receivers within the one or more candidate receivers. The subset of candidate receivers may correspond to a sidelink broadcast session or a sidelink groupcast session.

In operation 203, the UE performs a resource selection procedure by taking the set of resources into account, to select a transmission resource. In operation 204, the UE transmits, to the specific candidate receiver or the subset of candidate receivers, a data transmission on the selected transmission resource.

In an embodiment, if the one or more candidate receivers include only one candidate receiver (e.g., Rx UE 103b illustrated and shown in FIG. 1) and if the only one candidate receiver is within a sidelink unicast session, the set of resources corresponds to the only one candidate receiver.

In particular, with reference to FIG. 2, in operation 201, the UE (e.g., Tx UE 102 illustrated and shown in FIG. 1) transmits, to another UE (e.g., coordination UE 101 illustrated and shown in FIG. 1) , information regarding only one candidate receiver (i.e., Rx UE 103b illustrated and shown in FIG. 1) . The only one candidate receiver is within a sidelink unicast session. In operation 202, the UE receives, from the abovementioned another UE, signaling which indicates a set of resources in time and/or frequency domains, and the set of resources corresponds to the only one candidate receiver (i.e., Rx UE 103b illustrated and shown in FIG. 1) . In operation 203, the UE performs a resource selection procedure by taking the indicated set of resources into account. In operation 204, the UE transmits, to the only one candidate receiver (i.e., Rx UE 103b illustrated and shown in FIG. 1) , a data transmission in the sidelink unicast session on a transmission resource selected by the resource selection procedure of the UE.

In another embodiment, if the one or more candidate receivers transmitted by the UE in operation 201 includes only one candidate receiver and if the only one candidate receiver is within a sidelink broadcast session or a sidelink groupcast session, the set of resources corresponds to the sidelink broadcast session or the sidelink groupcast session.

In particular, with reference to FIG. 2, in operation 201, the UE (e.g., Tx UE 102 illustrated and shown in FIG. 1) transmits, to another UE (e.g., coordination UE 101 illustrated and shown in FIG. 1) , information regarding only one candidate receiver (e.g., Rx UE 103a illustrated and shown in FIG. 1) . The only one candidate receiver belongs to a sidelink broadcast session or a sidelink groupcast session (e.g., group#1 including Rx UE 103a and Rx UE 103b as illustrated and shown in FIG. 1) , and the information may include a destination ID of the sidelink broadcast session or the sidelink groupcast session. In operation 202, the UE receives, from the abovementioned another UE, signaling which indicates a set of resources in time and/or frequency domains, and the set of resources corresponds to the groupcast session or the broadcast session (i.e., group#1 as illustrated and shown in FIG. 1) . In operation 203, the UE performs a resource selection procedure by taking the indicated set of resources into account. In operation 204, the UE transmits, to all Rx UEs in the groupcast session or the broadcast session (i.e., Rx UE 103a and Rx UE 103b in group#1 as illustrated and shown in FIG. 1) , a data transmission in the groupcast session or the broadcast session on a transmission resource selected by the resource selection procedure of the UE.

In a further embodiment, if the one or more candidate receivers include two or more candidate receivers (e.g., Rx UE 103c and Rx UE 103d illustrated and shown in FIG. 1) , the abovementioned another UE (e.g., coordination UE 101 illustrated and shown in FIG. 1) may select one candidate receiver (e.g., Rx UE 103d illustrated and shown in FIG. 1) or a subset of candidate receivers (e.g., group#1 including Rx UE 103a and Rx UE 103b as illustrated and shown in FIG. 1) from these two or more candidate receivers. The UE (e.g., Tx UE 102 illustrated and shown in FIG. 1) may receive, from the abovementioned another UE, information regarding an ID of the selected one candidate receiver (e.g., a destination ID of Rx UE 103c illustrated and shown in FIG. 1) or an ID of the selected subset of candidate receivers (e.g., a destination ID of group#1 as illustrated and shown in FIG. 1) .

In particular, with reference to FIG. 2, after the UE transmits, to another UE, information regarding two or more candidate receivers in operation 201, the abovementioned another UE selects one candidate receiver from these two or more candidate receivers. In operation 202, the UE receives, from the abovementioned another UE, signaling which indicates a set of resources in time and/or frequency domains, and the set of resources corresponds to the selected one candidate receiver or the selected subset of candidate receivers. The UE also receives, from the abovementioned another UE, an ID (e.g., a destination ID) of the selected one candidate receiver or an ID (e.g., a destination ID) of the selected subset of candidate receivers. In operation 203, the UE performs a resource selection procedure by taking the indicated set of resources into account. In operation 204, the UE transmits, to the selected one candidate receiver or the selected subset of candidate receivers, a data transmission on a transmission resource selected by the resource selection procedure of the UE.

Details described in the embodiments as illustrated and shown in FIGS. 1 and 3-5, especially, contents related to receiving signaling indicating a set of resources in time and/or frequency domains, are applicable for the embodiments as illustrated and shown in FIG. 2. Moreover, details described in the embodiments of FIG. 2 are applicable for all the embodiments of FIGS. 1 and 3-5.

FIG. 3 illustrates a further exemplary flow chart of a method for indicating a set of resources according to some embodiments of the present application.

The embodiments of FIG. 3 may be performed by a UE (e.g., coordination UE 101 illustrated and shown in FIG. 1 or UE (a) illustrated and shown in FIG. 4) . Although described with respect to a UE, it should be understood that other devices may be configured to perform a method similar to that of FIG. 3.

In the exemplary method 300 as shown in FIG. 3, in operation 301, a UE (e.g., coordination UE 101 illustrated and shown in FIG. 1) receives, from another UE (e.g., Tx UE 102 illustrated and shown in FIG. 1) , information regarding one or more candidate receivers.

The embodiments of FIG. 3 assume that the abovementioned another UE (e.g., Tx UE 102 illustrated and shown in FIG. 1) works in Mode 2. That is to say, a sidelink resource in the time and/or frequency domains for a sidelink transmission of the abovementioned another UE is decided by the UE (e.g., coordination UE 101 illustrated and shown in FIG. 1) . In the embodiments of FIG. 3, the UE functions as a coordination UE, the candidate receiver (s) functions as a Rx UE (s) , and the abovementioned another UE functions as a Tx UE.

According to some embodiments, the information regarding one or more candidate receivers transmitted in operation 301 includes a set of one or more identifiers (IDs) corresponding to the one or more candidate receivers. For instance, the set of one or more IDs includes destination IDs of the one or more candidate receivers.

According to some embodiments, the information regarding one or more candidate receivers transmitted in operation 301 is included in a sidelink BSR. For example, the UE determines one candidate receiver or a subset of candidate receivers through a LCP procedure based on the sidelink BSR which includes the information regarding one or more candidate receivers. The subset of candidate receivers may correspond to a sidelink broadcast session or a sidelink groupcast session. A specific example is described in FIG. 4.

According to some embodiments, the information regarding one or more candidate receivers is transmitted or carried by at least one of physical channel information (e.g., a 2nd stage SCI) and high layer signaling (e.g., sidelink RRC signaling or a sidelink MAC CE) of the abovementioned another UE (e.g., Tx UE 102 illustrated and shown in FIG. 1) .

Referring back to FIG. 3, in operation 302, the UE transmits, to the abovementioned another UE, signaling which indicates a set of resources in time and/or frequency domains. The set of resources corresponds to one specific candidate receiver within the one or more candidate receivers. Then, the abovementioned another UE performs a resource selection procedure by taking the indicated set of resources into account to select a transmission resource and transmits, to the specific candidate receiver, a data transmission on the selected transmission resource.

In particular, with reference to FIG. 3, in operation 301, the UE (e.g., coordination UE 101 illustrated and shown in FIG. 1) receives, from another UE (e.g., Tx UE 102 illustrated and shown in FIG. 1) , information regarding only one candidate receiver (i.e., Rx UE 103b illustrated and shown in FIG. 1) . The only one candidate receiver is within a sidelink unicast session. In operation 302, the UE transmits, to the abovementioned another UE, signaling which indicates a set of resources in time and/or frequency domains corresponding to the only one candidate receiver (i.e., Rx UE 103b illustrated and shown in FIG. 1) . Then, the abovementioned another UE may perform a resource selection procedure by taking the set of resources into account, and transmit, to the only one candidate receiver (i.e., Rx UE 103b illustrated and shown in FIG. 1) , a data transmission in the sidelink unicast session on a transmission resource selected during the resource selection procedure.

In another embodiment, if the one or more candidate receivers received by the UE in operation 301 includes only one candidate receiver and if the only one candidate receiver is within a sidelink broadcast session or a sidelink groupcast session, the set of resources corresponds to the sidelink broadcast session or the sidelink groupcast session.

In particular, with reference to FIG. 3, in operation 301, the UE (e.g., coordination UE 101 illustrated and shown in FIG. 1) receives, from another UE (e.g., Tx UE 102 illustrated and shown in FIG. 1) , information regarding only one candidate receiver (e.g., Rx UE 103b illustrated and shown in FIG. 1) . The only one candidate receiver belongs to a sidelink broadcast session or a sidelink groupcast session (e.g., group#1 including Rx UE 103a and Rx UE 103b as illustrated and shown in FIG. 1) , and the information may include a destination ID of the sidelink broadcast session or the sidelink groupcast session. In operation 302, the UE transmits, to the abovementioned another UE, signaling which indicates a set of resources in time and/or frequency domains, and the set of resources corresponds to the groupcast session or the broadcast session (i.e., group#1 as illustrated and shown in FIG. 1) . Then, the abovementioned another UE may perform a resource selection procedure by taking the set of resources into account, and transmit, to all Rx UEs in the groupcast session or the broadcast session (i.e., Rx UE 103a and Rx UE 103b in group#1 as illustrated and shown in FIG. 1) , a data transmission in the groupcast session or the broadcast session on a transmission resource selected by the resource selection procedure of the UE.

In a further embodiment, if the one or more candidate receivers include two or more candidate receivers (e.g., Rx UE 103c and Rx UE 103d illustrated and shown in FIG. 1) , the UE (e.g., coordination UE 101 illustrated and shown in FIG. 1) may select one candidate receiver (e.g., Rx UE 103d illustrated and shown in FIG. 1) or a subset of candidate receivers (e.g., group#1 including Rx UE 103a and Rx UE 103b as illustrated and shown in FIG. 1) from these two or more candidate receivers. The UE may transmit, to the abovementioned another UE (e.g., Tx UE 102 illustrated and shown in FIG. 1) , information regarding an ID of the selected one candidate receiver (e.g., a destination ID of Rx UE 103c illustrated and shown in FIG. 1) or an ID of the selected subset of candidate receivers (e.g., a destination ID of group#1 as illustrated and shown in FIG. 1) .

In particular, with reference to FIG. 3, in operation 301, the UE receives, from the abovementioned another UE, information regarding two or more candidate receivers. Then, the UE selects one specific candidate receiver from these two or more candidate receivers. In operation 302, the UE transmits, to the abovementioned another UE, signaling which indicates a set of resources corresponding to the selected one candidate receiver or the selected subset of candidate receivers. The UE also transmits, to the abovementioned another UE, an ID (e.g., a destination ID) of the selected one candidate receiver or an ID (e.g., a destination ID) of the selected subset of candidate receivers. The abovementioned another UE performs a resource selection procedure by taking the set of resources into account, and transmits, to the selected one candidate receiver or the selected subset of candidate receivers, a data transmission on a transmission resource selected by the resource selection procedure.

Details described in the embodiments as illustrated and shown in FIGS. 1, 2, 4, and 5, especially, contents related to transmitting signaling indicating a set of resources in time and/or frequency domains, are applicable for the embodiments as illustrated and shown in FIG. 3. Moreover, details described in the embodiments of FIG. 3 are applicable for all the embodiments of FIGS. 1, 2, 4, and 5.

FIG. 4 illustrates an exemplary diagram of indicating a set of resources according to some embodiments of the present application.

The embodiments of FIG. 4 assume that UE (a) (e.g., coordination UE 101 illustrated and shown in FIG. 1) functions as a coordination UE, and UE (b) (e.g., Tx UE 102 illustrated and shown in FIG. 1) works in Mode 2 and functions as a Tx UE.

According to some embodiments, as shown in FIG. 4, in step 401, UE (b) , which functions as a Tx UE, transmits information regarding its candidate receiver (s) to UE (a) , which functions as a coordination UE. UE (a) may determine a set of resources according to the received information regarding the candidate receiver (s) . In step 402, UE (a) may send the set of resources to UE (b) with or without indicating the candidate receiver corresponding to the set of resources.

Specific Cases 1-4 of the embodiments of FIG. 4 are described as below.

Case 1

UE (b) transmits identity information (e.g., an ID) of only one candidate receiver to UE (a) . Then, UE (a) determines a set of resources in time and/or frequency domains for this candidate receiver of UE (b) ’s transmission. UE (a) transmits physical signaling or RRC signaling or a MAC CE indicating the set of resources to UE (b) . After receiving the physical signaling or RRC signaling or the MAC CE, UE (b) performs a resource selection procedure by taking the set of resources into account.

In short, in Case 1, since UE (b) transmits identity information of only one candidate receiver, UE (a) sends physical signaling or RRC signaling or a MAC CE indicating the set of resources corresponding to the only one candidate receiver to UE (b) , without needing to indicate or transmit the ID of the only one candidate receiver to which the set of resources corresponds. Based on the received physical signaling or RRC signaling or MAC CE, UE (b) may know or directly determine that the set of resources corresponds to the only one candidate receiver.

Case 2

UE (b) transmits identity information of two or more candidate receivers to UE (a) . For example, UE (b) transmits a set of index values of these two or more candidate receivers to UE (a) . UE (a) selects one candidate receiver or a subset of candidate receivers from these two or more candidate receivers, and determines a set of resources for this selected candidate receiver or the subset of candidate receivers of UE (b) ’s transmission. Then, UE (a) transmits physical signaling or RRC signaling or a MAC CE indicating the set of resources and also transmits the identity information of this selected candidate receiver or the subset of candidate receivers to UE (b) . For instance, UE (a) transmits a destination ID of this selected candidate receiver to UE (b) or a destination ID of the subset of candidate receivers. Alternatively, UE (a) transmits an index value of this selected candidate receiver or an index value of the subset of candidate receivers in the set of index values of these two or more candidate receivers.

In short, in Case 2, since UE (b) transmits identity information of two or more candidate receivers to UE (a) , besides sending physical signaling or RRC signaling or a MAC CE indicating a set of resources corresponding to the selected one candidate receiver to UE (b) , UE (a) needs to indicate or transmit the identity information of the selected one candidate receiver or the subset of candidate receivers to UE (b) . Based on the received physical signaling or RRC signaling or MAC CE and the received identity information, UE (b) may determine that the set of resources corresponds to the selected candidate receiver or the selected subset of candidate receivers.

Case 3

UE (b) transmits a sidelink BSR which includes identity information (e.g., an ID) of the candidate receiver (s) to UE (a) . According to the received sidelink BSR, UE (a) determines one candidate receiver of UE (b) ’s transmission by a LCP procedure. Then, UE (a) determines a set of resources for this determined one candidate receiver and transmits, to UE (b) , physical signaling or RRC signaling or a MAC CE indicating the set of resources. After receiving the physical signaling or RRC signaling or the MAC CE, UE (b) may perform a resource selection procedure by taking the set of resources into account.

In short, in Case 3, since UE (b) transmits a sidelink BSR which includes identity information of its candidate receiver (s) , UE (a) determines one candidate receiver based on the LCP procedure, and UE (b) may also determine the same candidate receiver based on the LCP procedure, UE (a) and UE (b) have the same understanding on the LCP procedure and the determined candidate receiver. Thus, UE (a) does not need to transmit the identity information of the determined candidate receiver to UE (b) . Based on the received physical signaling or RRC signaling or MAC CE, UE (b) may know or directly determine that the set of resources corresponds to the determined candidate receiver.

Case 4

UE (b) transmits a sidelink BSR which includes identity information of its candidate receiver (s) to UE (a) . For example, the sidelink BSR includes a set of index values of the candidate receiver (s) to UE (a) . According to the received sidelink BSR, UE (a) selects one candidate receiver from the candidate receiver (s) , and determines a set of resources for this selected candidate receiver. Then, UE (a) transmits physical signaling or RRC signaling or a MAC CE indicating the set of resources and also transmits the identity information of this selected candidate receiver to UE (b) . For instance, UE (a) transmits a destination ID of this selected candidate receiver to UE (b) . Alternatively, UE (a) transmits an index value of this selected candidate receiver in the set of index values of these two or more candidate receivers.

In short, in Case 4, since UE (b) transmits a sidelink BSR which includes identity information of its candidate receivers to UE (a) , besides sending physical signaling or RRC signaling or a MAC CE indicating a set of resources corresponding to the selected one candidate receiver to UE (b) , UE (a) needs to indicate or transmit the identity information of the selected one candidate receiver. Based on the received physical signaling or RRC signaling or MAC CE and the received identity information, UE (b) may determine that the set of resources corresponds to the selected candidate receiver.

Details described in the embodiments as illustrated and shown in FIGS. 1-3 and 5, especially, contents related to indicating a set of resources, are applicable for the embodiments as illustrated and shown in FIG. 4. Moreover, details described in the embodiments of FIG. 4 are applicable for all the embodiments of FIGS. 1-3 and 5.

FIG. 5 illustrates an exemplary block diagram of an apparatus according to some embodiments of the present application. In some embodiments of the present application, the apparatus 500 may be a UE, which can at least perform the method illustrated in any one of FIGS. 2-4.

As shown in FIG. 5, the apparatus 500 may include at least one receiver 502, at least one transmitter 504, at least one non-transitory computer-readable medium 506, and at least one processor 508 coupled to the at least one receiver 502, the at least one transmitter 504, and the at least one non-transitory computer-readable medium 506.

Although in FIG. 5, elements such as the at least one receiver 502, the at least one transmitter 504, the at least one non-transitory computer-readable medium 506, and the at least one processor 508 are described in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. In some embodiments of the present application, the at least one receiver 502 and the at least one transmitter 504 are combined into a single device, such as a transceiver. In certain embodiments of the present application, the apparatus 500 may further include an input device, a memory, and/or other components.

In some embodiments of the present application, the at least one non-transitory computer-readable medium 506 may have stored thereon computer-executable instructions which are programmed to implement the operations of the methods, for example as described in view of FIG. 2, FIG. 3, or FIG. 4, with the at least one receiver 502, the at least one transmitter 504, and the at least one processor 508.

Those having ordinary skills in the art would understand that the operations of a method described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. Additionally, in some aspects, the operations of a method may reside as one or any combination or set of codes and/or instructions on a non-transitory computer-readable medium, which may be incorporated into a computer program product.

While this disclosure has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations may be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in the other embodiments. Also, all of the elements of each figure are not necessary for operation of the disclosed embodiments. For example, those having ordinary skills in the art would be enabled to make and use the teachings of the disclosure by simply employing the elements of the independent claims. Accordingly, embodiments of the disclosure as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the disclosure.

In this document, the terms “includes, ” “including, ” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “a, ” “an, ” or the like does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element. Also, the term “another” is defined as at least a second or more. The term “having” and the like, as used herein, are defined as “including. ”

Claims

A method performed by a first user equipment (UE) , comprising:

transmitting, to a second UE, information regarding one or more candidate receivers;

receiving, from the second UE, signaling indicating a set of resources in at least one domain of time and frequency domains, wherein the set of resources corresponds to one candidate receiver or a subset of candidate receivers within the one or more candidate receivers;

performing a resource selection procedure by taking the set of resources into account, to select a transmission resource; and

transmitting, to the one candidate receiver or the subset of candidate receivers, a data transmission on the selected transmission resource.
The method of Claim 1, wherein the subset of candidate receivers corresponds to one of:

a sidelink broadcast session; and

a sidelink groupcast session.
The method of Claim 1, wherein:

in response to the one or more candidate receivers including only one candidate receiver and in response to the only one candidate receiver being within a sidelink unicast session, the set of resources corresponds to the only one candidate receiver; or

in response to the one or more candidate receivers including the only one candidate receiver and in response to the only one candidate receiver being within a sidelink broadcast session or a sidelink groupcast session, the set of resources corresponds to the sidelink broadcast session or the sidelink groupcast session; or

in response to the one or more candidate receivers including two or more candidate receivers:

the one candidate receiver or the subset of candidate receivers is selected, by the second UE, from the two or more candidate receivers, and

the method further comprises receiving information regarding an identity (ID) of the one candidate receiver or a ID of the subset of candidate receivers.
The method of Claim 1, wherein the information regarding one or more candidate receivers includes a set of destination IDs of the one or more candidate receivers.
The method of Claim 1, wherein the information regarding one or more candidate receivers is included in a sidelink buffer status report (BSR) .
The method of Claim 5, wherein the one candidate receiver or the subset of candidate receivers is determined by the second UE through a logical channel prioritization (LCP) procedure based on the sidelink BSR.
The method of Claim 1, wherein the information regarding one or more candidate receivers is transmitted in at least one of:

sidelink control information (SCI) ; and

high layer signaling of the first UE.
A method performed by a first user equipment (UE) , comprising:

receiving, from a second UE, information regarding one or more candidate receivers; and

transmitting, to the second UE, signaling indicating a set of resources in at least one domain of time and frequency domains, wherein the set of resources corresponds to one candidate receiver or a subset of candidate receivers within the one or more candidate receivers, and

wherein the set of resources is taken into account during a resource selection procedure, to select a transmission resource for a data transmission to the one candidate receiver or the subset of candidate receivers.
The method of Claim 8, wherein the subset of candidate receivers corresponds to one of:

a sidelink broadcast session; and

a sidelink groupcast session.
The method of Claim 8, wherein:

in response to the one or more candidate receivers including only one candidate receiver and in response to the only one candidate receiver being within a sidelink unicast session, the set of resources corresponds to the only one candidate receiver; or

in response to the one or more candidate receivers including the only one candidate receiver and in response to the only one candidate receiver being within a sidelink broadcast session or a sidelink groupcast session, the set of resources corresponds to the sidelink broadcast session or the sidelink groupcast session; or

in response to the one or more candidate receivers including two or more candidate receivers, the method further comprises:

selecting the one candidate receiver or the subset of candidate receivers from the two or more candidate receivers; and

transmitting information regarding an identity (ID) of the one candidate receiver or a ID of the subset of candidate receivers.
The method of Claim 8, wherein the information regarding one or more candidate receivers includes a set of destination IDs of the one or more candidate receivers.
The method of Claim 8, wherein the information regarding one or more candidate receivers is included in a sidelink buffer status report (BSR) .
The method of Claim 12, further comprising:

determining the one candidate receiver or the subset of candidate receivers through a logical channel prioritization (LCP) procedure based on the sidelink BSR.
The method of Claim 8, wherein the information regarding one or more candidate receivers is transmitted in at least one of:

sidelink control information (SCI) ; and

high layer signaling of the second UE.
An apparatus, comprising:

a non-transitory computer-readable medium having stored thereon computer-executable instructions;

a receiving circuitry;

a transmitting circuitry; and

a processor coupled to the non-transitory computer-readable medium, the receiving circuitry and the transmitting circuitry,

wherein the computer-executable instructions cause the processor to implement the method of any of Claims 1-14.