WO2024060310A1

WO2024060310A1 - Methods and apparatuses for multiple channel access for sidelink transmission on unlicensed spectrum

Info

Publication number: WO2024060310A1
Application number: PCT/CN2022/123273
Authority: WO
Inventors: Zhennian SUN; Haipeng Lei; Xiaodong Yu; Xin Guo
Original assignee: Lenovo Beijing Ltd
Current assignee: Lenovo Beijing Ltd
Priority date: 2022-09-30
Filing date: 2022-09-30
Publication date: 2024-03-28
Anticipated expiration: 2025-03-30

Abstract

The present application relates to methods and apparatuses for multiple channel access for sidelink transmission on an unlicensed spectrum. One embodiment of the present disclosure provides a first UE for wireless communication, comprising: a transceiver; and a processor coupled with the transceiver and configured to: receive, from a second UE, a first indication indicating an RB set associated with a type 1 LBT procedure performed by the second UE; and perform resource selection for SL transmission based on the first indication.

Description

METHODS AND APPARATUSES FOR MULTIPLE CHANNEL ACCESS FOR SIDELINK TRANSMISSION ON UNLICENSED SPECTRUM

TECHNICAL FIELD

The present disclosure relates to wireless communication, and particularly relates to methods and apparatuses for multiple channel access for sidelink transmission on an unlicensed spectrum.

BACKGROUND OF THE INVENTION

In an unlicensed spectrum, before any transmission, a base station (BS) or a user equipment (UE) may need to perform a listen before talk (LBT) procedure, and in the case that the LBT procedure is successful, the BS or the UE may perform the transmission, otherwise, the transmission cannot be performed. There are different types of LBT procedures, such as a type 1 LBT procedure or a type 2 LBT procedure.

For sidelink (SL) transmission on unlicensed spectrum, an SL UE may perform LBT procedure before any transmission. The frequency band for SL transmission may be 80MHz, which includes 4 resource block (RB) sets, each RB set with a bandwidth of 20MHz. The minimum granularity of an LBT procedure is one RB set, e.g., 20MHz. That is, the SL UE may perform an LBT procedure on one RB set, or more RB sets.

In some scenarios, an SL UE may perform SL transmission on multiple RB sets, may perform an LBT procedure on each of the RB sets, and may perform the SL transmission until the LBT procedure is successful on each of the RB sets occupied by the SL transmission.

Some issues exist in the multiple channel access for sidelink transmission on an unlicensed spectrum, and it is desirable to provide solutions for multiple channel access for sidelink on an unlicensed spectrum.

SUMMARY

One embodiment of the present disclosure provides a first UE for wireless communication, comprising: a transceiver; and a processor coupled with the transceiver and configured to: receive, from a second UE, a first indication indicating an RB set associated with a type 1 LBT procedure performed by the second UE; and perform resource selection for SL transmission based on the first indication.

In some embodiments, a selected resource is at least partially overlapped with the type 1 LBT procedure performed by the second UE in a time domain, and is in an RB set different from the RB set associated with the type 1 LBT procedure performed by the second UE.

In some embodiments, a resource is not selected in the case that the resource is at least partially overlapped with the type 1 LBT procedure performed by the second UE in a time domain, and is in a same RB set as the RB set associated with the type 1 LBT procedure performed by the second UE.

In some embodiments, the first indication is received via 1 ^st-stage sidelink control information (SCI) or 2 ^nd-stage SCI.

In some embodiments, the first indication further indicates a type of multiple channel access associated with the second UE.

In some embodiments, the processor is further configured to: select an RB set associated with a type 1 LBT performed by the first UE among at least one RB set randomly or based on a channel busy rate (CBR) measurement of each RB set, wherein a time duration for the type 1 LBT performed by the first UE in the at least one RB set is not overlapped with reserved resource (s) in a time domain.

In some embodiments, an RB set with a lowest CBR is selected.

In some embodiments, the processor is further configured to: transmit a second indication indicating the RB set associated with a type 1 LBT procedure performed by the first UE.

Another embodiment of the present disclosure provides a UE for wireless communication, comprising: a transceiver; and a processor coupled with the transceiver and configured to: select an RB set associated with a type 1 LBT procedure performed by the UE among at least one RB set, wherein a time duration for the type 1 LBT performed by the UE in the at least one RB set are not overlapped with time duration (s) of a reserved resource (s) in a time domain; and in the case that the type 1 LBT procedure is successful, perform a sidelink transmission.

In some embodiments, the processor is further configured to: select the RB set randomly or based on a CBR of each RB set.

In some embodiments, an RB set among the at least one RB set with a lowest CBR is selected.

In some embodiments, the processor is further configured to: not select an RB set in the case that the time duration for the type 1 LBT performed by the UE in the at least one RB set are overlapped with time duration (s) of a reserved resource (s) in the time domain.

In some embodiments, the processor is further configured to: transmit an indication indicating the RB set associated with a type 1 LBT procedure performed by the UE.

Yet another embodiment of the present disclosure provides a UE for wireless communication, comprising: a transceiver; and a processor coupled with the transceiver and configured to: receive a first indication indicating a resource (s) for sidelink transmission on at least one RB set, wherein the at least one RB set includes an RB set associated with a type 1 LBT procedure; and perform the sidelink transmission on the at least one RB set in the case that the type 1 LBT procedure is successful.

In some embodiments, the first indication further indicates an RB set associated with the type 1 LBT procedure.

In some embodiments, the first indication further indicates a type of multiple channel access associated with the UE.

In some embodiments, further comprising: transmit a second indication indicating a CBR of each RB set of the at least one RB set.

In some embodiments, the processor is further configured to: determine an RB set with a lowest CBR among the at least one RB set as the RB set associated with a type 1 LBT procedure.

Yet another embodiment of the present disclosure provides a method for multiple channel access performed by a first UE, comprising: receiving, from a second UE, a first indication indicating an RB set associated with a type 1 LBT procedure performed by the second UE; and performing resource selection for SL transmission based on the first indication.

Yet another embodiment of the present disclosure provides a method for multiple channel access, comprising: selecting an RB set associated with a type 1 LBT procedure performed by the UE among at least one RB set, wherein a time duration for the type 1 LBT performed by the UE in the at least one RB set are not overlapped with time duration (s) of a reserved resource (s) in a time domain; and in the case that the type 1 LBT procedure is successful, performing a sidelink transmission.

Yet another embodiment of the present disclosure provides a method for multiple channel access, comprising: receiving a first indication indicating a resource (s) for sidelink transmission on at least one RB set, wherein the at least one RB set includes an RB set associated with a type 1 LBT procedure; and performing the sidelink transmission on the at least one RB set in the case that the type 1 LBT procedure is successful.

BRIEF DESCRIPTION OF THE DRAWINGS

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

Fig. 1 illustrates a schematic diagram of a wireless communication system according to some embodiments of the present disclosure.

Fig. 2A illustrates a resource selection procedure according to some embodiments of the present disclosure.

Fig. 2B illustrates another resource selection procedure according to some embodiments of the present disclosure.

Fig. 3A illustrates a resource selection procedure according to some embodiments of the present disclosure.

Fig. 3B illustrates another resource selection procedure according to some embodiments of the present disclosure.

Fig. 4A illustrates a resource allocation by the BS according to some embodiments of the present disclosure.

Fig. 4B illustrates another resource allocation by the BS according to some embodiments of the present disclosure.

Fig. 5 illustrates a method performed by a first UE for multiple channel access for sidelink transmission on an unlicensed spectrum according to some embodiments of the present disclosure.

Fig. 6 illustrates a method performed by a UE for multiple channel access for sidelink transmission on an unlicensed spectrum according to some embodiments of the present disclosure.

Fig. 7 illustrates a method performed by a UE for multiple channel access for sidelink transmission on an unlicensed spectrum according to some embodiments of the present disclosure.

Fig. 8 illustrates a simplified block diagram of an apparatus according to some embodiments of the present disclosure.

DETAILED DESCRIPTION

The detailed description of the appended drawings is intended as a description of the currently preferred embodiments of the present invention, and is not intended to represent the only form in which the present invention 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 invention.

While operations are depicted in the drawings in a particular order, persons skilled in the art will readily recognize that such operations need not be performed in the particular order as shown or in a sequential order, or that all illustrated operations need be performed, to achieve desirable results; sometimes one or more operations can be skipped. Further, the drawings can schematically depict one or more example processes in the form of a flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In certain circumstances, multitasking and parallel processing can be advantageous.

Reference will now be made in detail to some embodiments of the present disclosure, 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 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 3 ^rd generation partnership project (3GPP) -based network, LTE, LTE-Advanced (LTE-A) , 3GPP 4G, 3GPP 5G NR, 3GPP Release 16 and onwards, a satellite communications network, a high altitude platform network, and so on. It is contemplated that along with the developments of network architectures and new service scenarios, all embodiments in the present disclosure are also applicable to similar technical problems; and moreover, the terminologies recited in the present disclosure may change, which should not affect the principle of the present disclosure.

UE under an NR SL-U scenario may be referred to as an SL UE (s) . An SL UE which transmits data on sidelink in an unlicensed spectrum may be referred to as a UE for transmitting, a transmitting UE, a transmitting SL UE, a Tx SL UE, a Tx UE, an SL Tx UE, an SL BWP Tx UE, a UE, or the like. An SL UE which receives data on sidelink in an unlicensed spectrum may be referred to as a UE for receiving, a receiving UE, a receiving SL UE, an Rx UE, an Rx SL UE, an SL Rx UE, a UE, or the like.

An SL UE (s) 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) , internet of things (IoT) devices, personal computer (PC) , game terminal, extended reality (XR) devices, or the like.

According to some embodiments of the present disclosure, an SL UE (s) 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.

According to some embodiments of the present disclosure, an SL UE (s) may include wearable devices, such as smart watches, fitness bands, optical head-mounted displays, or the like. Moreover, an SL UE (s) 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. An SL UE (s) may communicate directly with a BS(s) via communication signals.

A BS under an NR SL-U scenario may be referred to as a base unit, a base, an access point, an access terminal, a macro cell, a Node-B, an enhanced Node B (eNB) , a gNB, a Home Node-B, a relay node, a device, a remote unit, or by any other terminology used in the art. A BS may be distributed over a geographic region. Generally, a BS is a part of a radio access network that may include one or more controllers communicably coupled to one or more corresponding base stations.

A BS is generally communicably coupled to one or more packet core networks (PCN) , which may be coupled to other networks, like the packet data network (PDN) (e.g., the Internet) and public switched telephone networks, among other networks. These and other elements of radio access and core networks are not illustrated but are well known generally by those having ordinary skill in the art. For example, one or more BSs may be communicably coupled to a mobility management entity (MME) or an access and mobility management function (AMF) , a serving gateway (SGW) , a packet data network gateway (PGW) , and/or or a user plane function (UPF) .

A BS may serve a number of SL UEs within a serving area, for example, a cell or a cell sector via a wireless communication link. A BS may communicate directly with one or more SL UEs via communication signals. For example, a BS may serve SL UEs within a macro cell.

Sidelink communication between a Tx UE and a receiving (Rx) UE under an NR SL-U scenario includes groupcast communication, unicast communication, or broadcast communication.

Fig. 1 illustrates wireless communication system 100 (e.g., an SL-U communication system) in accordance with some embodiments of the present disclosure.

As shown in Fig. 1, the wireless communication system 100 includes a base station (e.g., BS 102) , and some UEs (e.g., UE 101-A, UE 101-B, UE 101-C, and UE 101-D) . UE 101-A and UE 101-B are within the coverage of BS 102, and UE 101-C and UE 101-D are outside the coverage of BS 102. UE 101-A, UE 101-B, UE 101-C, and UE 101-D may perform sidelink unicast transmission, sidelink groupcast transmission, or sidelink broadcast transmission in an unlicensed spectrum, such as the SL BWP. UE 101-A, UE 101-B, UE 101-C, and UE 101-D may be referred to as SL UEs. It is contemplated that, in accordance with some other embodiments of the present disclosure, an SL-U communication system may include more BSs and more or fewer SL UEs.

In addition, although the SL UEs as shown in Fig. 1 are illustrated in the shape of a cellphone, it is contemplated that an SL communication system may include any type of UE (e.g., a roadmap device, a cell phone, a computer, a laptop, an IoT device or other type of device) in accordance with some other embodiments of the present disclosure.

According to some embodiments of Fig. 1, UE 101-A may function as a Tx UE, and UE 101-B, UE 101-C, and UE 101-D may function as Rx UEs. UE 101-Amay exchange SL messages with UE 101-B or UE 101-C through a sidelink using, for example, NR technology or LTE technology, through PC5 interface as defined in 3GPP documents. UE 101-A may transmit information or data to another UE (s) within the SL-U communication system through sidelink unicast, sidelink groupcast, or sidelink broadcast. For instance, UE 101-A may transmit data to UE 101-B in a sidelink unicast session. UE 101-A may transmit data to UE 101-B and UE 101-C in a groupcast group by a sidelink groupcast transmission session. Also, UE 101-Amay transmit data to UE 101-B and UE 101-C by a sidelink broadcast transmission session.

Alternatively, according to some other embodiments of Fig. 1, UE 101-B or UE 101-C may function as a Tx UE and transmit information or data, and UE 101-Amay function as an Rx UE and receive information or data from UE 101-B or UE 101-C.

Both UE 101-A and UE 101-B in the embodiments of Fig. 1 may transmit information to BS 102 and receive control information from BS 102, for example, via a Uu interface. BS 102 may define one or more cells, and each cell may have a coverage area. As shown in Fig. 1, both UE 101-A and UE 101-B are within the coverage of BS 102, while UE 101-C and UE 101-D are not.

The BS 102 as illustrated and shown in Fig. 1 may not be a specific base station, but may be any base station (s) in the SL-U communication system. For example, assuming that the SL-U communication system includes two BSs, UE 101-A being within a coverage area of any one the two BSs may be called a case where UE 101-A is within the coverage of a BS in the SL-U communication system; and only UE 101-A being outside of a coverage area (s) of both BSs may be called a case where UE 101-A is outside of the coverage of a BS in the SL-U communication system.

UEs may operate in different modes. At least the following two sidelink resource allocation modes are defined for sidelink communication: resource allocation mode 1: a BS may schedule a sidelink resource (s) to be used by a UE for sidelink transmission (s) ; and resource allocation mode 2: a UE may determine a sidelink transmission resource (s) within sidelink resources configured by a BS or network, or pre-configured sidelink resources. In resource allocation mode 2, a BS may not schedule the sidelink resources for a UE. In Fig. 1, UE 101-A and UE 101-B may be in resource allocation mode 1, and UE 101-C and UE 101-D may be in resource allocation mode 2. In some other cases, UE 101-A and UE 101-B may also operate in resource allocation mode 2. Hereinafter in the present disclosure, "mode 1" may refer to resource allocation mode 1, and "mode 2" may refer to resource allocation mode 2.

In the R16 NR unlicensed spectrum (NR-U) , multiple-channel access is supported for both downlink (DL) transmission and uplink (UL) transmission, wherein for DL transmission, two types of multiple-channel access procedures are defined as follows:

Type A: the BS performs an independent type 1 LBT procedure on each RB set; and

Type B: the BS randomly selects an RB set for the type 1 LBT procedure and performs the type 2 LBT procedure on other RB sets.

For SL transmission, similar types of multiple-channel access procedures may be as follows:

Type A: the SL UE performs an independent type 1 LBT procedure on each RB set; and

Type B: the SL UE randomly selects an RB set for the type 1 LBT procedure and performs the type 2 LBT procedure on other RB sets.

The type 1 LBT procedure and type 2 LBT procedure are different, in particular, the type 1 LBT procedure may be longer than the type 2 LBT procedure in the time domain, for example, the type 1 LBT procedure may last for a number of slots, while the type 2 LBT procedure may last around 25μs. It is assumed that the type 2 LBT procedure may be performed during the gap between different transmissions, in other words, it is assumed that the resources for the type 2 LBT procedure may be used for other UEs to perform the SL transmission.

Different lengths of the type 1 LBT duration and the type 2 LBT duration may impact the resource selection for UEs in resource allocation mode 2, if the LBT duration is considered during the resource selection, and the different LBT durations may also impact UEs in resource allocation mode 1.

In the present disclosure, several issues and solutions for multiple-channel access in an unlicensed spectrum for UEs in both mode 1 and mode 2 are provided.

Issue 1:

For wideband operation, a UE, e.g., UE #1, may randomly select the RB set for the type 1 LBT procedure, but may not inform other UEs. For a UE in resource allocation mode 2, e.g., UE #2, UE #2 may exclude all the resources on all the RB sets which may block the type 1 LBT procedure of the reserved resources by UE #1.

In Fig. 2A, 4 RB sets, RB set #0, RB set #1, RB set #2, and RB set #3, are included in the SL frequency band.

UE #1 may perform a SL transmission with resources 201 on RB set #1, RB set #2, and RB set #3, and may reserve the resources 203 on RB set #1, RB set #2, and RB set #3. Before the SL transmission with resources 203, UE #1 may perform the type 1 LBT procedure on RB set #1, and perform the type 2 LBT procedure on RB set #2 and RB set #3. However, UE #1 does not indicate the RB set on which UE #1 may perform the type 1 LBT procedure. That is, UE #1 does not indicate to other UEs that it will perform the type 1 LBT procedure on RB set #1.

UE #2 may also perform a SL transmission, and may perform sensing before the resource selection for the SL transmission. UE #2 may detect that UE #1 has reserved resources 203 on RB set #1, RB set #2 and RB set #3. However, UE #2 does not know on which RB set UE #1 may perform the type 1 LBT procedure. To protect the type 1 LBT procedure of UE #1, UE #2 may not select the all the resources on RB set #1, RB set #2 and RB set #3 which overlap the type 1 LBT duration of UE #1, even when UE #1 may only perform the type 1 LBT procedure on RB set #1. That is, UE #2 may not select the resources indicated as 204 in Fig. 2A. Accordingly, spectrum efficiency is decreased.

Solution 1

The present disclosure proposes a solution for improving spectrum efficiency. In particular, it is proposed that the UE may indicate the RB set on which it will perform the type 1 LBT procedure, to assist the resource selection of other UEs.

UE #1 may perform SL transmission with resources 211 on RB set #1, RB set #2, and RB set #3, and may reserve resources 213 on RB set #1, RB set #2, and RB set #3. In Fig. 2B, in addition to transmitting the resource reservation, UE #1 may also transmit an indication, that indicates the RB set for the type 1 LBT procedure, e.g., indicating RB set #1 for the type 1 LBT procedure, which means that UE #1 may perform the type 1 LBT procedure on RB set #1. The indication may be transmitted in the SCI, for example, 1 ^st-stage SCI or 2 ^nd -stage SCI.

UE #2 may also perform SL transmission, and may perform sensing before the resource selection for the SL transmission. UE #2 may receive the resource reservation with multiple RB sets, furthermore, UE #2 may receive the indication indicating the RB set for the type 1 LBT procedure from the UE #1. UE #2 may not select the resource at least partially overlaps the type 1 LBT duration on the indicated RB set in the time domain, and may select the resources on the other RB sets that partially overlaps the type 1 LBT duration. For example, UE #2 may not select resource that at least partially overlaps the resource 212 on RB set #1, but may select the resources 214, which overlap resource 212 in the time domain, but are in a different RB set.

UE #1 may select the RB set for the type 1 LBT procedure based on random selection, and may transmit an indication indicating the randomly selected RB set. For example, UE #1 may randomly select one RB set from RB set #1, RB set #2, and RB set #3, and transmit the SCI indicating the selected RB set.

Alternatively, UE #1 may measure the CBR for each RB set for the multiple RB sets associated with the SL transmission, and select the RB set with the lowest CBR. For example, in Fig. 2B, UE #1 may perform SL transmission on 3 RB sets, RB set #1, RB set #2, and RB set #3, and UE #1 may measure the CBR for each RB set and select the RB set with the lowest CBR.

Issue 2:

The type B multiple channel access may be configured for an SL UE, that is, the SL UE may randomly select an RB set for the type 1 LBT procedure from multiple RB sets. During the resource selection procedure, the SL UE may not select a resource if the type 1 LBT procedure for the resource on any RB set of the multiple RB sets may be blocked by reserved resources.

The UE may be configured with type B multiple channel access, and may perform a resource selection procedure to select a resource with 3 RB sets. The UE may detect the reservation from another UE (s) , which may reserve resources 302 on RB set #1 and RB set #2. For resource 304 with 3 RB sets, if the UE selects resource 304, the UE needs to perform the type 1 LBT procedure (for the SL transmission on resource 304) on an RB set, which is randomly selected from RB set #1, RB set #2, and RB #3. However, as can be seen in Fig. 3A, the type 1 LBT procedure on RB set #1 and RB set #2 may overlap the reserved resources 302 on RB set #1 and RB set #2, respectively. In other words, the type 1 LBT procedure on RB set #1 and RB set #2 may be blocked by the reserved resources 302. According to type B multiple channel access, the UE may randomly select the RB set for the type 1 LBT procedure from all RB sets, which means the UE may perform the type 1 LBT procedure on RB set #1 or RB set #2, while the resources on RB set #1 or RB set #2 for the type 1 LBT procedure are blocked by reserved resources 302. Therefore, the UE cannot select resources 304 even though the UE may perform the type 1 LBT procedure on RB set #3 and perform the type 2 LBT procedure on RB set #1 and RB set #2.

Solution 2

In order to solve the above problem, the present disclosure proposes that the UE may select a resource with multiple RB sets in the case that the type 1 LBT procedure on at least one RB set among the multiple RB sets that are not be blocked by the reserved resources. The UE may further determine the RB set for the type 1 LBT procedure among the at least one RB set which is not blocked by the reserved re sources.

For example, in Fig. 3A, the UE may select RB set #3, and perform the type 1 LBT procedure on RB set #3, which is not blocked by the reserved resources.

UE #1 may perform SL transmission with resources 311 on RB set #1, and may reserve the resources 312 on RB set #1. UE #2 may select resources 314, because the type 1 LBT procedure (which is for the SL transmission on resources 314) on either RB set #2 or RB set #3 is not blocked by the reserved resource 312. UE #1 may select the RB set for the type 1 LBT procedure from RB set #2 and RB set #3 randomly, or based on the CBR, in particular, UE #1 may select an RB set with a lower CBR.

In some embodiments, after UE #2 has selected the resources for the type 1 LBT procedure, UE #2 may transmit an indication, e.g., SCI, to other UEs. Other UEs, may receive this indication, and may perform the operations as described in Fig. 5.

Issue 3:

In some embodiments, the SL UE may be in resource allocation mode 1, and the resources for sidelink transmission are scheduled or granted by the BS. When the SL UE is scheduled on resources with multiple RB sets, and the RB set for the type 1 LBT procedure is determined by the SL UE, the BS may always reserve a gap for the type 1 LBT procedure on all the allocated RB sets. According to type B multiple channel access, the SL UE may randomly select an RB set for the type 1 LBT procedure and performs the type 2 LBT procedure on other RB sets, therefore, the gap for the type 1 LBT procedure on other allocated RB sets may be wasted. The gap for the type 1 LBT procedure on all allocated RBs may decrease spectrum efficiency, especially for a long type 1 LBT duration, e.g., several slots.

The BS may allocate resource 402 on RB set #1, RB set #2 and RB set #3 for an SL UE for sidelink transmission. The BS may further reserve a gap for the type 1 LBT procedure on all the allocated RB sets, for example, the gap 401 on RB set #1, RB set #2 and RB set #3 for the type 1 LBT procedure of the SL UE. The BS may not allocate the resources that overlap the type 1 LBT procedure on RB set #1, RB set #2 and RB set #3, which may decrease spectrum efficiency especially for a long type 1 LBT duration, e.g., several slots.

Solution 3-1

In the case that resources on multiple RB sets are allocated to the SL UE in mode 1, the BS may transmit an indication which indicates the RB set among the multiple RB sets for the type 1 LBT procedure. The indication may be transmitted via DCI together with the resource allocation.

The BS may allocate resources 412 on RB set #1, RB set #2 and RB set #3 for an SL UE for sidelink transmission. The BS may further indicate the RB set for the type 1 LBT procedure, e.g., the BS may indicate RB set #1 for the type 1 LBT procedure.

In this way, the BS may still allocate resources on RB set #2 and RB set #3, for example, resources 413, although they overlaps the type 1 LBT duration for the UE in the time domain, they are on a different RB set from the RB set for the type 1 LBT procedure. Thus spectrum efficiency is improved.

Solution 3-2

In this solution, the BS may not indicate the RB set among the multiple RB sets for the type 1 LBT procedure.

The SL UE may transmit an indication to indicate a CBR of each RB set of the multiple RB sets. When the BS schedules resources on multiple RB sets for the SL UE, the BS may always assume that the SL UE may perform the type 1 LBT procedure on the RB set with the lowest CBR. At the SL UE side, after receiving resource allocation with multiple RB sets, the SL UE may always performs the type 1 LBT procedure on an RB set with the lowest CBR.

In this way, both the BS and the SL UE have the same understanding regarding the RB set for the type 1 LBT procedure of the SL UE. The BS may further allocate resources on other RB sets, which may overlap the RB set with the lowest CBR in the time domain for other use, thus spectrum efficiency is improved.

In some embodiments, the type A multiple channel access or the type B multiple channel access may be configured per resource pool, wherein the above embodiments are only applicable for the resource pool configured with type B multiple channel access.

In some other embodiments, the type A multiple channel access or the type B multiple channel access may be configured per UE or up to UE implementation. Therefore, in the same resource pool, there may be a UE (s) configured with type A multiple channel access, and a UE (s) configured with type B multiple channel access. In this case, in the SCI or DCI, the type may be indicated for the UE. In the case that the UE is configured with type B multiple channel access, the SCI or DCI may further indicate the RB set for the type 1 LBT procedure.

In operation 501, the first UE may receive, from a second UE, a first indication indicating an RB set associated with a type 1 LBT procedure performed by the second UE; and in operation 502, the first UE may perform resource selection for SL transmission based on the first indication. For example, as shown in Fig. 2B, the first UE may receive an indication indicating the second UE may perform a type 1 LBT procedure on RB set #1. The first UE may perform the resource selection based on the indication.

In some embodiments, a selected resource is at least partially overlapped with the type 1 LBT procedure performed by the second UE in a time domain, and is in an RB set different from the RB set associated with the type 1 LBT procedure performed by the second UE. For example, referring to Fig. 2B, a selected resource may include the resource indicated as 214, which overlaps the type 1 LBT procedure performed by the second UE in the time domain and in a different RB set.

In some embodiments, the first indication further indicates a type of multiple channel access associated with the second UE. For example, the first indication may indicate that the second UE is configured with type B multiple channel access.

In some embodiments, the first UE may select an RB set associated with a type 1 LBT performed by the first UE among at least one RB set randomly or based on a CBR measurement of each RB set, wherein a time duration for the type 1 LBT performed by the first UE in the at least one RB set are not overlapped with reserved resource (s) in a time domain. For example, in Fig. 3B, the first UE may select an RB set from RB set #2 and RB set #3 randomly, or RB set #3 when RB set #3 has a lower CBR measurement. In some embodiments, an RB set with a lowest CBR is selected.

In some embodiments, the first UE may transmit a second indication indicating the RB set associated with a type 1 LBT procedure performed by the first UE.

In operation 601, the UE may select an RB set associated with a type 1 LBT procedure performed by the UE among at least one RB set, wherein a time duration for the type 1 LBT performed by the UE in the at least one RB set are not overlapped with a time duration (s) of a reserved resource (s) in a time domain. In operation 602, in the case that the type 1 LBT procedure is successful, the UE may perform a sidelink transmission. For example, in Fig. 3B, the UE may select RB set #3, and the type 1 LBT procedure performed in RB set #3 does not overlap a time duration (s) of a reserved resource (s) in a time domain.

In some embodiments, the UE may select the RB set randomly or based on a CBR of each RB set. In some embodiments, an RB set among the at least one RB set with a lowest CBR is selected.

In some embodiments, the UE may not select an RB set in the case that the time duration for the type 1 LBT performed by the UE in the at least one RB set are overlapped with time duration (s) of a reserved resource (s) in the time domain.

In some embodiments, the UE may transmit an indication indicating the RB set associated with a type 1 LBT procedure performed by the UE.

In operation 701, the UE may receive a first indication indicating a resource (s) for sidelink transmission on at least one RB set, wherein the at least one RB set includes an RB set associated with a type 1 LBT procedure. In operation 702, the UE may and perform the sidelink transmission on the at least one RB set in the case that the type 1 LBT procedure is successful.

In some embodiments, the first indication further indicates a type of multiple channel access associated with the UE. In some embodiments, the UE may transmit a second indication indicating a CBR of each RB set of the at least one RB set.

In some embodiments, the UE may determine an RB set with a lowest CBR among the at least one RB set as the RB set associated with a type 1 LBT procedure.

As shown in Fig. 8, an example of the apparatus 800 may include at least one processor 804 and at least one transceiver 802 coupled to the processor 804. The apparatus 800 may be a UE, a BS, or any other device with similar functions.

Although in this figure, elements such as the at least one transceiver 802 and processor 804 are described in the singular, the plural is contemplated unless a limitation to the singular is explicitly stated. In some embodiments of the present disclosure, the transceiver 802 may be divided into two devices, such as a receiving circuitry and a transmitting circuitry. In some embodiments of the present disclosure, the apparatus 800 may further include an input device, a memory, and/or other components.

In some embodiments of the present disclosure, the apparatus 800 may be a UE. The transceiver 802 and the processor 804 may interact with each other so as to perform the operations of the UE described in any of Figs. 1-7.

In some embodiments of the present disclosure, the apparatus 800 may further include at least one non-transitory computer-readable medium.

For example, in some embodiments of the present disclosure, the non-transitory computer-readable medium may have stored thereon computer-executable instructions to cause the processor 804 to implement the method with respect to the UE as described above. For example, the computer-executable instructions, when executed, cause the processor 804 interacting with transceiver 802 to perform the operations of the UE described in any of Figs. 1-7.

In some embodiments of the present disclosure, the non-transitory computer-readable medium may have stored thereon computer-executable instructions to cause the processor 804 to implement the method with respect to the BS as described above. For example, the computer-executable instructions, when executed, cause the processor 804 interacting with transceiver 802 to perform the operations of the BS described in any of Figs. 1-7.

The method of the present disclosure can be implemented on a programmed processor. However, controllers, flowcharts, and modules may also be implemented on a general purpose or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an integrated circuit, a hardware electronic or logic circuit such as a discrete element circuit, a programmable logic device, or the like. In general, any device that has a finite state machine capable of implementing the flowcharts shown in the figures may be used to implement the processing functions of the present disclosure.

While the present disclosure has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in other embodiments. Also, all of the elements shown in each figure are not necessary for operation of the disclosed embodiments. For example, one skilled in the art of the disclosed embodiments would be capable of making and using the teachings of the present disclosure by simply employing the elements of the independent claims. Accordingly, the embodiments of the present 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 present disclosure.

In this disclosure, relational terms such as "first, " "second, " and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises, " "comprising, " or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises 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 comprises the element. Also, the term "another" is defined as at least a second or more. The terms "including, " "having, " and the like, as used herein, are defined as "comprising. "

Claims

A first user equipment (UE) for wireless communication, comprising:

a transceiver; and

a processor coupled with the transceiver and configured to:

receive, from a second UE, a first indication indicating a resource block (RB) set associated with a type 1 listen before talk (LBT) procedure performed by the second UE; and

perform resource selection for sidelink (SL) transmission based on the first indication.
The first UE of Claim 1, wherein a selected resource is at least partially overlapped with the type 1 LBT procedure performed by the second UE in a time domain, and is in an RB set different from the RB set associated with the type 1 LBT procedure performed by the second UE.
The first UE of Claim 1, wherein a resource is not selected in the case that the resource is at least partially overlapped with the type 1 LBT procedure performed by the second UE in a time domain, and is in a same RB set as the RB set associated with the type 1 LBT procedure performed by the second UE.
The first UE of Claim 1, wherein the first indication is received via 1 ^st-stage sidelink control information (SCI) or 2 ^nd-stage SCI.
The first UE of Claim 1, wherein the first indication further indicates a type of multiple channel access associated with the second UE.
The first UE of Claim 1, wherein the processor is further configured to:

select an RB set associated with a type 1 LBT performed by the first UE among at least one RB set randomly or based on a channel busy rate (CBR) measurement of each RB set, wherein a time duration for the type 1 LBT performed by the first UE in the at least one RB set is not overlapped with reserved resource (s) in a time domain.
The first UE of Claim 6, wherein an RB set with a lowest CBR is selected.
The first UE of Claim 6, wherein the processor is further configured to:

transmit a second indication indicating the RB set associated with a type 1 LBT procedure performed by the first UE.
A user equipment (UE) for wireless communication, comprising:

a transceiver; and

a processor coupled with the transceiver and configured to:

select a resource block (RB) set associated with a type 1 listen before talk (LBT) procedure performed by the UE among at least one RB set, wherein a time duration for the type 1 LBT performed by the UE in the at least one RB set is not overlapped with time duration (s) of reserved resource (s) in a time domain; and

in the case that the type 1 LBT procedure is successful, perform a sidelink transmission.
The UE of Claim 9, wherein the processor is further configured to:

select the RB set randomly or based on a channel busy rate (CBR) of each RB set.
The UE of Claim 10, wherein an RB set among the at least one RB set with a lowest CBR is selected.
The UE of Claim 9, wherein the processor is further configured to:

not select an RB set in the case that the time duration for the type 1 LBT performed by the UE in the at least one RB set is overlapped with time duration (s) of reserved resource (s) in the time domain.
The UE of Claim 9, wherein the processor is further configured to:

transmit an indication indicating the RB set associated with a type 1 LBT procedure performed by the UE.
A user equipment (UE) for wireless communication, comprising:

a transceiver; and

a processor coupled with the transceiver and configured to:

receive a first indication indicating resource (s) for sidelink transmission on at least one resource block (RB) set, wherein the at least one RB set includes an RB set associated with a type 1 listen before talk (LBT) procedure; and

perform the sidelink transmission on the at least one RB set in the case that the type 1 LBT procedure is successful.
The UE of Claim 14, wherein the first indication further indicates an RB set associated with the type 1 LBT procedure.