CN117643142A

CN117643142A - Method and apparatus for inter-User Equipment (UE) cooperation in side-link (SL) communication

Info

Publication number: CN117643142A
Application number: CN202280049023.4A
Authority: CN
Inventors: 岳国森; 布莱恩·克拉松; 维普尔·德赛
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-08-05
Filing date: 2022-08-04
Publication date: 2024-03-01

Abstract

According to an embodiment, a first UE (e.g., UE a) receives side uplink control information (sidelink control information, SCI) from a second UE (e.g., UE B) in a first time slot. The SCI includes resource reservation of a shared channel. The resource reservation indicates a set of frequency resources and a time resource allocation. The first UE sends a collision indicator to the second UE on a resource of a feedback channel. The resources of the feedback channel include a second time slot for transmitting the collision indicator. The location of the second time slot is based on one of the following time slots: the first time slot or the time slot indicated by the time resource allocation. The conflict indicator indicates a potential resource conflict or a detected resource conflict on at least one of the following objects: a set of frequency resources of the resource reservation indication or a time resource allocation of the resource reservation indication.

Description

Method and apparatus for inter-User Equipment (UE) cooperation in side-link (SL) communication

Cross Reference to Related Applications

The present patent application claims priority from U.S. provisional application No. 63/230,548 entitled "method and apparatus for inter-UE collaboration in side-uplink communications (Method and Apparatus of Inter UE Coordinations in Sidelink Communications)" filed on 8 th month 6 of 2021, and U.S. provisional application No. 63/229,866 entitled "method and apparatus for inter-UE collaboration in side-uplink communications (Method and Apparatus of Inter UE Coordinations in Sidelink Communications)" filed on 5 th month 2021, the contents of which are incorporated herein by reference as if fully reproduced herein.

Technical Field

The present disclosure relates generally to wireless communications, and in particular embodiments, to techniques and mechanisms for inter-UE collaboration in Sidelink (SL) communications.

Background

The third generation partnership project (third generation partnership project,3 GPP) has been developing and standardizing some features related to the fifth generation (5G) new air interface (NR) access technology. In Release-16, a work item of NR internet of things (V2X) wireless communication was completed with the aim of providing a high-speed reliable connection compatible with 5G for vehicle communication. The work item provides the basis for NR-side uplink communications for security systems and autopilot applications. High data rates, low latency, and high reliability are some of the key aspects of research and standardization.

Disclosure of Invention

Embodiments of the present disclosure describe a method and apparatus for power saving UEs to conduct side-link communications in a shared resource pool, generally achieving technical advantages.

In some embodiments, the collision indicator may indicate a sensed-based potential resource collision on the time resource allocation or a detected resource collision on the time resource allocation, or the collision indicator may indicate a sensed-based potential resource collision on the set of frequency resources or a detected resource collision on the set of frequency resources. In some embodiments, the location of the second time slot may be immediately after the first time slot plus a time interval. In some embodiments, the location of the second time slot may be the shortest time before the time slot of the time resource allocation indication. In some embodiments, the location of the second time slot based on one of the first time slot or the time slot indicated by the time resource allocation may be configured by a base station or predefined. In some embodiments, the first UE may be a destination of the shared channel transmitted from the second UE. In some embodiments, the feedback channel may be a physical side uplink feedback channel (physical sidelink feedback channel, PFSCH). In some embodiments, the enablement of transmitting the conflict indicator may be configured by higher layer signaling. In some embodiments, the SCI may further include 1-bit information indicating that the second UE is capable of receiving the collision indicator from the first UE. In some embodiments, the SCI may include fewer reserved bits when the second UE is to transmit the 1-bit information. In some embodiments, the first UE may monitor a set of frequency resources indicated by the time resource allocation in the SCI. In some embodiments, the feedback channel may include a first set of resources and a second set of resources. The first set of resources may carry an Acknowledgement (ACK) or a Negative ACK (NACK) for a received shared channel, and the second set of resources may include resources of the feedback channel carrying the collision indicator. In some embodiments, the first set of resources and the second set of resources may be located on different frequency resources. In some embodiments, the first UE may send the collision indicator to the second UE according to a priority indicated in the SCI.

According to an embodiment, a second UE (e.g., UE B) sends side uplink control information (sidelink control information, SCI) to a first UE (e.g., UE a) in a first time slot. The resource reservation indicates a set of frequency resources and a time resource allocation. The second UE receives a collision indicator from the first UE on a resource of a feedback channel. The resources of the feedback channel include a second time slot for receiving the collision indicator. The location of the second time slot is based on one of the following time slots: the first time slot or the time slot indicated by the time resource allocation. The conflict indicator indicates a potential resource conflict or a detected resource conflict on at least one of the following objects: a set of frequency resources of the resource reservation indication or a time resource allocation of the resource reservation indication.

In some embodiments, the collision indicator may indicate a sensed-based potential resource collision on the time resource allocation or a detected resource collision on the time resource allocation, or the collision indicator may indicate a sensed-based potential resource collision on the set of frequency resources or a detected resource collision on the set of frequency resources. In some embodiments, the location of the second time slot may be immediately after the first time slot plus a time interval. In some embodiments, the location of the second time slot may be the shortest time before the time slot of the time resource allocation indication. In some embodiments, the location of the second time slot based on one of the first time slot or the time slot indicated by the time resource allocation may be configured by a base station or predefined. In some embodiments, the first UE may be a destination of the shared channel transmitted from the second UE. In some embodiments, the feedback channel may be a physical side uplink feedback channel (physical sidelink feedback channel, PFSCH). In some embodiments, the enablement of receiving the conflict indicator may be configured by higher layer signaling. In some embodiments, the SCI may further include 1-bit information indicating that the second UE is capable of receiving the collision indicator from the first UE. In some embodiments, the SCI may include fewer reserved bits when the second UE is to transmit the 1-bit information. In some embodiments, the feedback channel includes a first set of resources that may carry an Acknowledgement (ACK) or a Negative ACK (NACK) for a received shared channel and a second set of resources that may include resources of the feedback channel that carry the collision indicator. In some embodiments, the first set of resources and the second set of resources may be located on different frequency resources. In some embodiments, the second UE may receive the collision indicator from the first UE according to a priority indicated in the SCI.

The above aspects solve the technical problems described in the present disclosure, thereby reducing resource conflicts, improving resource utilization efficiency, improving side-uplink communication performance, and reducing side-uplink power consumption.

Drawings

For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic diagram of an exemplary communication system;

FIG. 2 is a schematic diagram of an exemplary in-coverage (IC) scenario and out-of-coverage (OOC) scenario in side-link communications;

FIG. 3 is a schematic diagram of an exemplary resource pool;

fig. 4 is a schematic diagram of exemplary resources for a physical side uplink control channel (physical sidelink control channel, PSCCH), a physical side uplink shared channel (physical sidelink shared channel, PSSCH), and a physical side uplink feedback channel (physical sidelink feedback channel, PSFCH);

FIGS. 5A and 5B illustrate how resources provided by some embodiments are associated with PSFCH;

FIG. 6A illustrates one example of a hidden node problem;

FIG. 6B illustrates one example of an exposed node problem;

FIG. 6C illustrates one example of a half-duplex problem;

Fig. 6D shows an example of a continuous packet loss problem;

FIG. 7 illustrates slot-subchannel assignments for PSFCH or PSFCH-like channels provided by some embodiments using PSFCH associated with an originally scheduled PSSCH as a reference for collaborative information transmission;

fig. 8 illustrates alternative slot-subchannel assignments for PSFCH or PSFCH-like channels provided by some embodiments for cooperative information transmission;

FIG. 9 illustrates virtual PSSCH concepts of resource allocation of PSFCH or PSFCH-like channels for collaborative information transfer provided by some embodiments;

fig. 10 illustrates a process provided by some embodiments for inter-UE collaboration over a feedback channel;

fig. 11 illustrates selection of PSFCH among two PSFCH PRB sets provided by some embodiments;

FIG. 12 illustrates PSFCH resource partitioning in the code domain provided by some embodiments;

FIG. 13 illustrates PSFCH resource partitioning in the frequency domain provided by some embodiments;

FIG. 14 illustrates exemplary collaboration information in a MAC-CE provided by some embodiments;

fig. 15A illustrates a flow chart of a method for inter-UE collaboration in SL communication provided by some embodiments;

fig. 15B illustrates a flow chart of a method for inter-UE collaboration in SL communication provided by some embodiments;

FIG. 16 is a schematic diagram of another exemplary communication system;

FIG. 17A is a schematic diagram of an exemplary End Device (ED);

FIG. 17B is a schematic diagram of an exemplary base station;

FIG. 18 is a block diagram of an exemplary computing system.

Corresponding numerals and symbols in the various drawings generally indicate corresponding parts unless otherwise indicated. The figures are drawn for clarity of illustration of relevant aspects of the embodiments and are not necessarily drawn to scale.

Detailed Description

The making and using of the embodiments of the present disclosure are discussed in detail below. However, it should be understood that the concepts disclosed herein may be embodied in a wide variety of specific contexts and that the specific embodiments discussed herein are merely illustrative and are not intended to limit the scope of the claims. Further, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims.

In Release-17, a sidelink enhanced work item is approved to further enhance the capabilities and performance of sidelink communications. One of the goals of this work item is to introduce a UE collaboration mechanism, where one UE (e.g., UE a) provides information about resources to another UE (e.g., UE B) for UE B to make resource selections.

In this disclosure, several techniques are described that support inter-UE collaboration. Although these techniques may be used for all UEs, they are particularly applicable to Public Safety (PS) UEs. More detail is provided below.

Fig. 1 is a schematic diagram of an exemplary communication system 100. Communication system 100 includes an access node 110 having a coverage area 101. Access node 110 serves User Equipment (UE), e.g., UE 120. The access node 110 is connected to a backhaul network 115, the backhaul network 115 providing connectivity to services and the internet. In a first mode of operation, communications to and from the UE pass through the access node 110. In the second mode of operation, communications to and from the UE do not pass through the access node 110, however, the access node 110 will typically allocate resources for the UE to communicate when specific conditions are met. Communication between pairs of UEs in the second mode of operation occurs over a side uplink 125 that includes a unidirectional communication link. The communication in the second mode of operation may be referred to as side-link communication. Communication between the UE and the access node pair also occurs over a unidirectional communication link, where the communication link from UE 120 to access node 110 is referred to as uplink 130 and the communication link from access node 110 to UE 120 is referred to as downlink 135.

An access Node may also be generally referred to as a Node B, evolved Node B (eNB), next Generation (NG) Node B (NG Node B, gNB), master eNB (MeNB), secondary eNB (SeNB), master nb (MgNB), secondary nb (sbb), network controller, control Node, base station, access point, transmission point (transmission point, TP), transmission-reception point (TRP), cell, carrier, macrocell, femtocell, picocell, etc. A UE may also be generally referred to as a mobile station, handset, terminal, user, subscriber, station, etc. The access node may provide wireless access according to one or more wireless communication protocols of the third generation partnership project (Third Generation Partnership Project,3 GPP) long term evolution (long term evolution, LTE), LTE-advanced (LTE-a), 5G LTE, 5G NR, sixth generation (6G), high speed packet access (High Speed Packet Access, HSPA), IEEE 802.11 series standards such as 802.11a/b/G/n/ac/ad/ax/ay/be, and the like. Although it will be appreciated that a communication system may use multiple access nodes capable of communicating with multiple UEs, only one access node and two UEs are shown for simplicity.

The side-link communications may be in the coverage area or outside the coverage area. For operation in mode 1, i.e., in-coverage (IC) operation, there may be a central node (e.g., access node, eNB, gNB, etc.) for managing the side links. For operation in mode 2, the operation of the system is fully distributed, with the UE selecting resources by itself. Operation in mode 2 is for out-of-coverage scenarios as well as for IC scenarios. Fig. 2 is a schematic diagram of an exemplary IC scenario 200 and an exemplary OOC scenario 250. In IC scenario 200, the gNB 202 is used to manage side-link communications between UEs 204 and 206 within the coverage of the gNB 202. UEs 204 and 206 may be considered mode 1 UEs. In OOC scenario 250, UEs 252 and 254 perform mutual sidelink communications without central node management and select resources for sidelink communications themselves. UEs 252 and 254 may be considered as mode 2 UEs. In one embodiment of the present disclosure, some UEs may be assisted or assisted in selecting respective resources for side-link communication.

For side-link communication, the concept of resource pool is introduced for LTE side-links, while the concept of NR side-link multiplexing. The resource pool is a collection of resources that can be used for side-link communications. The resources in the resource pool may be configured for different channels and signals, e.g., control channels, shared channels, feedback channels, broadcast channels (e.g., primary information blocks), synchronization signals, reference signals, and so forth. 3GPP TS 38.331v16.4.1"NR published 30.2021.3; radio Resource Control (RRC); the protocol specification (NR; radio Resource Control (RRC); protocol specification), the entire contents of which are incorporated herein by reference, defines rules on how to share resources in a resource pool and for a particular configuration of the resource pool. A UE performing a sidelink transmission may select one resource from a pool of resources configured for sidelink communication and transmit a signal in the resource through the sidelink.

The resource pool for side-link communication may be configured using physical resource blocks (physical resource block, PRBs) or subchannels in time slots and frequency domains in time domain. One sub-channel may include one or more PRBs. Fig. 3 is a diagram 300 of an exemplary resource pool in a time-frequency resource grid. Fig. 3 shows a resource pool 310 comprising a plurality of resources (hatched rectangle) in different time slots and PRBs/sub-channels.

3GPP TS 38.211v16.5.0"NR published under 2021, 3 and 30; physical channel and modulation (NR; physical channels and modulation) ", the entire contents of which are incorporated herein by reference, for NR mobile broadband (MBB), each physical resource block (physical resource block, PRB) in the grid is defined to comprise 12 consecutive subcarriers in the time domain and the time slot consisting of 14 consecutive orthogonal frequency division multiplexing (orthogonal frequency division multiplexing, OFDM) symbols, that is, each resource block comprises 12×14 Resource Elements (REs). Each RE includes one subcarrier. (PRB, when used as frequency domain unit, is 12 consecutive subcarriers.) when a conventional cyclic prefix is used, 14 symbols are included in a slot; when an extended cyclic prefix is used, 12 symbols are included in the slot. The duration of the symbol is inversely proportional to the subcarrier spacing (subcarrier spacing, SCS). For {15, 30, 60, 120} kHz SCS, the time slot durations are {1,0.5,0.25,0.125} ms, respectively. PRBs may be allocated for transmission of channels and/or signals, e.g., control channels, shared channels, feedback channels, reference signals, or a combination thereof. In addition, part of REs in PRBs may be reserved. The side-links may also use similar time-frequency resource structures. The communication resources used for side-uplink communication, etc., may be PRBs, PRB sets, codes (similar to codes used for physical uplink control channel (physical uplink control channel, PUCCH) if code division multiple access (code division multiple access, CDMA) is used), physical sequences, RE sets, or combinations thereof.

As described herein, a UE participating in a sidelink communication is referred to as a source UE or a transmitting UE when it is to transmit a signal to another UE on the sidelink. When a UE engaged in a side-link communication is to receive a signal from another UE on the side-link, the UE is referred to as a destination UE, a receiving (receiving/receiving) UE, or a recipient. Two UEs communicating with each other on the side-link are also referred to as a UE pair in side-link communication.

The physical side-link control channel (physical sidelink control channel, PSCCH) may carry side-link control information (sidelink control information, SCI). The source UE uses the SCI to schedule or reserve resources for data transmission on the physical side uplink shared channel (physical sidelink shared channel, PSSCH). The SCI may indicate time and frequency resources of the PSSCH and/or parameters for a hybrid automatic repeat request (hybrid automatic repeat request, HARQ) process, e.g., redundancy version, process ID (or ID), new data indicator, and resources for a physical side uplink feedback channel (physical sidelink feedback channel, PFSCH). The time and frequency resources of the PSSCH may be referred to as resource allocation (assignment) and may be indicated in a time resource allocation field and/or a frequency resource allocation field (i.e., resource location). The PFSCH may carry an indication (e.g., HARQ acknowledgement (HARQ-ACK) or negative acknowledgement (HARQ-NACK)) indicating whether the destination UE correctly decodes the payload carried on the PSSCH. The SCI may also carry a bit field that indicates or identifies the source UE. In addition, the SCI may carry a bit field that indicates or identifies the destination UE. The SCI may also include other fields to carry information such as modulation coding scheme used to encode the payload and modulate the encoded payload bits, demodulation reference signal (demodulation reference signal, DMRS) pattern, antenna port, priority of the payload (transmission), etc. The sensing UE performs sensing on the side-link, i.e. receives a PSCCH transmitted by another UE, decodes SCI carried in the PSCCH to obtain resource information reserved by the other UE, and determines resources used by the sensing UE for side-link transmission.

Fig. 4 is a block diagram for PSCCH, PSSCH and objectSchematic diagram 400 of an exemplary resource of a process-side uplink feedback channel (physical sidelink feedback channel, PSFCH). Fig. 4 shows the resources in time slot n and time slot n+1. In slot n, there is a resource region 402 of the PSCCH, a resource region 404 of the PSSCH (PSSCH as shown) _m ) Resource region 406 of the PSFCH. In slot n+1, there is a resource region 422 for PSCCH, a resource region 424 for PSSCH (PSSCH as shown) _k ) And a resource region 426 of the PSFCH.

In NR, there are two stages of SCI: a first stage SCI (shown below) and a second stage SCI. The first level SCI may indicate resources for the second level SCI. The first stage SCI may be transmitted in the PSCCH. The second stage SCI may be transmitted in the PSSCH. SCI may have the following format: SCI format 1-A, SCI format 2-a and SCI format 2-B.

SCI format 1-a: first stage SCI of a type

SCI format 1-a is used to schedule PSSCH and secondary SCI on the PSSCH (3GPP TS38.212v16.5.0"NR; multiplexing and channel coding (NR; multiplexing and channel coding) according to release 2021, 3, 30, the entire contents of which are incorporated herein by reference).

The following information is sent via SCI format 1-a:

-priority level: 3 bits as described in section 5.4.3.3 of TS23.287 and section 5.22.1.3.1 of TS 38.321.

-frequency resource allocation: when the value of the higher layer parameter sl-MaxNumPerReserve is configured to be 2A number of bits; otherwise, the value of the higher layer parameter sl-MaxNumPerReserve is configured to be 3Bits as described in section 8.1.5 of TS 38.214.

-time resource allocation: the value of the higher layer parameter sl-MaxNumPerReserve is 5 bits when 2 is configured; otherwise, the value of the higher layer parameter sl-MaxNumPerReserve is configured to 9 bits when 3, as described in section 8.1.5 of TS 38.214.

-resource reservation period: configured with higher-layer parameters sl-MultiReserve resourceBits, where N _{rsv_period} Is the number of entries in the higher layer parameter sl-resourceReserve PeriodList; otherwise, 0 bits, as described in 16.4 of TS 38.213.

-DMRS pattern:bits, where N _pattern Is the number of DMRS patterns configured by the higher layer parameter sl-PSSCH-DMRS-TimePatternList, as described in section 8.4.1.1.2 of TS 38.211.

Second level SCI format: 2 bits as described in table 8.3.1.1-1 of TS 38.212.

Beta_offset indicator: 2 bits as described in table 8.3.1.1-2 of the higher layer parameters sl-BetaOffsets2ndSCI and TS 38.212.

-DMRS port number: 1 bit as described in table 8.3.1.1-3 of TS 38.212.

-modulation coding scheme: 5 bits as described in section 8.1.3 of TS 38.214.

-an additional MCS table indicator: configuring 1 bit when an MCS Table through a high-level parameter sl-Additional-MCS-Table; 2 bits when two MCS tables are configured through a high-level parameter sl-Additional-MCS-Table; otherwise, 0 bits, as described in section 8.1.3.1 of TS 38.214.

-PSFCH overhead indication: 1 bit when higher layer parameter sl-PSFCH-period=2 or 4; otherwise, 0 bits, as described in section 8.1.3.2 of TS 38.214.

-reservation: the number of bits, determined by the higher layer parameter sl-numreservadbis, is set to zero.

TS 38.321 v16.4.0 "third Generation partnership project published on month 29 of 2021; technical specification group radio access network; NR; media Access Control (MAC) protocol specification (Release 16) (3rd Generation Partnership Project;Technical Specification Group Radio Access Network;NR;Medium Access Control (MAC) protocol specification (Release 16)) "ts23.287v16.5.0" third generation partnership project published under month 12 of 2020; technical specification group services and system aspects; the entire contents of the architecture enhancements (16 th edition) of the 5G system (5 GS) supporting the vehicle universal (V2X) service (3rd Generation Partnership Project;Technical Specification Group Services and System Aspects;Architecture enhancements for 5G System (5 GS) to support Vehicle-to-evaluation (V2X) services (Release 16)) are incorporated herein by reference.

SCI format 2-a: second stage SCI of a type

SCI format 2-a is used to decode the PSSCH, with HARQ operation when the HARQ-ACK information includes ACK or NACK, or when there is no feedback of HARQ-ACK information.

The following information may be sent over SCI format 2-a (according to 3gpp TS 38.212):

HARQ process number:section 16.4 "NR in bits, such as TS 38.213 v16.5.0 published 30 at 3/2021; the physical layer procedure for control (NR; physical layer procedures for control) ", the entire contents of which are incorporated herein by reference, is described.

-new data indication: 1 bit as described in section 16.4 of TS 38.213.

Redundancy version: 2 bits, such as section 16.4 "NR in TS 38.214 v16.5.0 published 30 at 3/2021; the physical layer procedure for data (NR; physical layer procedures for data) ", the entire contents of which are incorporated herein by reference, is described.

-source ID:8 bits as described in section 8.1 of TS 38.214.

-destination ID:16 bits as described in section 8.1 of TS 38.214.

-HARQ feedback enable/disable indicator: 1 bit as described in section 16.3 of TS 38.213.

-a transmission type indicator: 2 bits as described in table 8.4.1.1-1 of TS 38.212.

-CSI request: 1 bit as described in section 8.2.1 of TS 38.214.

Table 8.4.1.1-1 of TS 38.212 is provided below.

Table 8.4.1.1-1: transmission type indicator

Transmission type indicator value	Transmission type
		00	Broadcasting
01	Multicast
		10	Unicast of
11	Reservation

SCI format 2-B: another type of second stage SCI

SCI format 2-B is used to decode the PSSCH with HARQ operation when the HARQ-ACK information includes only NACK or when there is no feedback of HARQ-ACK information.

The following information may be sent via SCI format 2-B (according to TS 38.212):

HARQ process number:bits as described in section 16.4 of TS 38.213.

-new data indication: 1 bit as described in section 16.4 of TS 38.213.

Redundancy version: 2 bits as described in section 16.4 of TS 38.214.

-source ID:8 bits as described in section 8.1 of TS 38.214.

-destination ID:16 bits as described in section 8.1 of TS 38.214.

Region ID:12 bits as described in section 5.8.1.1 of TS 38.331, the entire contents of which are incorporated herein by reference.

-communication range requirements: 4 bits as described in TS 38.331.

TS 38.331 specifies higher layer messages for configuring the PSCCH and specifies the cells (information element, IE) SL-PSCCH-Config-r16 as follows:

SL-PSCCH-Config-r16::＝SEQUENCE{

sl-TimeResourcePSCCH-r16 ENUMERATED{n2,n3}OPTIONAL,--Need M

sl-FreqResourcePSCCH-r16 ENUMERATED{n10,n12,n15,n20,n25}OPTIONAL,--Need M

sl-DMRS-ScrambleID-r16 INTEGER(0..65535)OPTIONAL,--Need M

sl-NumReservedBits-r16 INTEGER(2..4)OPTIONAL,--Need M

...

}

in release 16, 3GPP introduced NR-side downlink communications between devices such as UEs in addition to typical downlink and uplink transmissions. Devices supporting side-link communications may exchange control information/data information with each other periodically.

In release 16, to reduce collision probability and improve packet rate (packet reception ratio, PRR) performance, two mechanisms of re-evaluation and preemption are introduced in side-uplink communications.

Re-evaluation mechanism: after the transmitting UE selects a side-link resource and reserves the selected side-link resource, the sensing procedure may continue to be performed to check whether the reserved resource is still available. To this end, the UE may continuously monitor the SCI on the side-uplink resources and perform a resource selection procedure, e.g., as described in section 8.1.4 of TS 38.214, to perform a resource exclusion procedure in a reduced resource selection window according to the sensing result to form an available resource set. If the reserved resources are not in the set of available resources, the UE performs a resource reselection and selects new resources to avoid any potential collision. For example, the UE may determine a set of resources from the resource pool that the UE may use for side-link communication. The UE may select one resource from the set of available resources and reserve the selected resource. The UE may then re-determine the set of resources by: for example, one or more unavailable resources are excluded (e.g., SCI reserved by another UE according to the received indication) or one or more available resources are added. The UE may check whether the selected resources are included in the re-determined set of resources (or referred to as an updated set of resources). If the selected resource is not included in the re-determined set of resources (which may indicate that the resource is no longer available to the UE), the UE may reselect one resource from the re-determined set of resources for sidelink communications.

Preemption mechanism: after the transmitting UE (e.g., UE 1) selects and reserves the side-link resources, the sensing procedure may continue to check whether the reserved resources are still available, as described above. In one example, UE1 may discover that the reserved resource is not included in the updated set of available resources and is occupied by another UE (e.g., UE 2) by: for example, SCI 1-A from UE2 is decoded. UE2 may be referred to as a conflicting UE. In this case, UE1 may detect the priority of data to be transmitted by UE 2. If the priority of the data to be transmitted by UE1 (referred to as the sensing UE when performing the sensing procedure) is lower than the priority of the data of UE2, the sensing UE (UE 1) may release its reserved resources and reselect one resource in a resource selection window (e.g., in the updated set of available resources). If the data of UE1 has a higher priority, UE1 may continue to reserve the resource and transmit its own data on the sidelink using the reserved resource.

The side-uplink data traffic has 8 packet priorities, 1, 2 … … indicated by the 3-bit number P in the priority field in SCI format 1-a. The value of p is from 0 to 7, and the value of priority (priority/priority level) is equal to p+1. It should be noted that, according to TS23.303 "proximity services (ProSe) in 16.0.0 published 7/9/2020; stage2 (ProSe; stage 2), the entire contents of which are incorporated herein by reference, a smaller (small/lower) value (p+1) of priority indicates a higher priority (priority/priority level). The minimum value 1 of the priorities indicates the highest priority, and the maximum value 8 of the priorities indicates the lowest priority.

The priority of the side-uplink data may be set by the application layer and provided to the physical layer.

For unicast and multicast, acknowledgement (ACK)/Negative ACK (NACK) feedback may be configured and transmitted in a physical side uplink feedback channel (physical sidelink feedback channel, PSFCH). At this time, associated PSFCH resources are transmitted for each physical side uplink shared channel (physical sidelink shared channel, PSSCH). Fig. 5A and 5B illustrate the manner in which resources are associated with a PSFCH. Fig. 5A shows PRB set allocation and PRB to PFSCH mapping. The period of the PSFCH is n=4, and the PRB set for the PSFCH is 4 per subchannel. The minimum number of slots for PSFCH latency is k=2. In one example, the PSSCH may occupy 2 sub-channels (N _sub =2). FIG. 5B shows a mapping of PSFCH, where M _S Number of cyclic shifts n=5 PRBs per PRB resource set _CS ＝2。

As shown in fig. 5A, each PSSCH transmission is associated with one PSFCH or set of PSFCHs. The resources for the PSFCH may be configured to be available once every N slots, where N is the PSFCH period (n=4 in fig. 5A). There is also processing delay. Therefore, the interval between the slot for the PSFCH and the corresponding PSSCH slot is not less than K. In the example shown in fig. 5A, k=2. Since n=4, there are 4 PRB resources per subchannel Sets, each set corresponding to a PSFCH association. If PSSCH transmission occupies more than one sub-channel, e.g. N _sub Sub-channel, PSFCH can be selected from N _sub And selecting from the PRB resource sets. As shown in fig. 5A, one PSSCH transmission occupies two sub-channels (on PSSCH sets 5 and 9 of PRB resources). The corresponding PSFCH may be from N _sub The set of PRB resources is selected, i.e. the last set 5 and 9 to be used for PSFCH association. Alternatively, if PSSCH occupies N _sub >1 subchannel, the UE may still select one PRB resource set for PSFCH allocation, i.e. based on the starting subchannel. For the same example shown in fig. 5A, the PSFCH may be associated only in set 5 by two sub-channels. M is present in each PRB resource set _S Each PRB may be allocated for one PSFCH transmission. In addition, the same PRBs may be multiplexed for additional PSFCH transmissions by different cyclic shifts of the sequence for HARQ-ACKs. The number of times N of cyclic shift of multiplexing factor _CS And (5) determining. N (N) _CS May be configured according to {1,2,3,6 }. Thus, for occupying N _sub PSSCH of sub-channel if N of PRB resource is used _sub The PSFCH sets share l=n _sub *M _S *N _CS The PSFCH resources, if one PRB resource set corresponding to the PSSCH starting subchannel is used, share l=m _S *N _CS And PSFCH resources. In the example of FIG. 5B, M _S ＝5，N _CS =2, the two PRB resource sets correspond to the PSSCH with 2 subchannels in fig. 5. There are 20 PSFCH resources in total. The rule defined in release 16 of 5G NR is that the receiving UE selects the jth PSFCH resource according to the following equation:

j＝(T _ID +R _ID )mod L

in the above equation, T _ID Is the layer 1ID of the transmitting UE (i.e., source ID in the second level SCI), R is for unicast ACK/NACK feedback or multicast option 1 NACK feedback only _ID =0. For multicast option 2 ACK/NACK feedback, R _ID Is the receiver ID in the multicast from the higher layer. As shown in fig. 5B, in an exemplary case, j=7.

The NCS and corresponding cyclic shift pair index configuration is as described in table 16.3-1 of TS 38.213, and is reversed as follows.

Table 163-1: cyclic shift pair set (picking TS 38213)

The HARQ-ACK 1 bit message is also carried by sequences comprising different cyclic shifts. The mapping of cyclic shift indexes to ACK/NACKs is as described in table 16.3-2 of TS 38.213, i.e., 0 represents NACK and 6 represents ACK. For multicast option 1HARQ, only NACK messages are sent on the PSFCH, requiring only one NACK state. A mapping of NACK messages, i.e. 0 for NACK, is provided in table 16.3-3 of TS 38.213, which coincides with the value of ACK/NACK feedback.

Table 16.3-2: mapping of HARQ-ACK information bit values to cyclic shifts in cyclic shift pairs of sequences for PSFCH transmission when the HARQ-ACK information includes an ACK or NACK

HARQ-ACK values	0(NACK)	1(ACK)
			Cyclic shift of sequences	0	6

Table 16.3-3: mapping of HARQ-ACK information bit values to cyclic shifts in cyclic shift pairs of sequences for PSFCH transmission when the HARQ-ACK information includes only NACKs

HARQ-ACK values	0(NACK)	1(ACK)
			Cyclic shift of sequences	0	N/A

On the ranp#86 conference, release 17 work item (RP-193257) was agreed on regarding side-uplink enhancements, the goals of resource allocation enhancements for improving side-uplink reliability are as follows:

● Considering PRR and Packet Inter-Reception (PIR) as described by TR 37.885 (ran#91), one or more enhanced feasibility and benefits of enhancing reliability and reducing delay in mode 2 are studied and a certain scheme is specified where considered feasible and beneficial [ RAN1, RAN2].

inter-UE collaboration including:

■ UE a determines a set of resources. The set is sent to UE B in mode 2 and UE B considers this when selecting resources for its own transmissions.

In release 16 NR V2X side uplinks, mode 2 UEs transmit and receive information without network management. The UE allocates resources from the resource pool itself for side-uplink transmission. However, since in release 16 the transmitter performs sensing and resource selection, there are several technical problems that degrade the side-link performance, such as:

● Hidden node problem

● Exposed node problem

● Half duplex problem

● And continuously packet loss.

Fig. 6A shows an example of a hidden node problem. In fig. 6A, UE B604 selects resources for data transmission to UE a 602. Since the resource selection is performed by UE B604 based on its own sensing result, if UE C606 is not within coverage area 605 of UE B604, UE B604 will not detect the reservation of resources by UE C606. Then, when UE B604 and UE C606 select the same resources (e.g., the same resources in the time and frequency domains) for their respective transmissions, collisions may occur. Since the transmission of UE C606 may interfere, UE a 602 may not be able to receive the transmission of UE B604, whether UE a 602 is the recipient of the transmission of UE C606 or not.

Fig. 6B illustrates one example of an exposed node problem. In fig. 6B, both UE B614 and UE C616 select resources and transmit to UE a 612 and UE D618, respectively. Since UE B614 and UE C616 are within coverage of each other, UE B614 and UE C616 may select different resources (e.g., different resources in the time and/or frequency domains) to avoid collisions based on their sensing results. However, since UE a 612 is outside the coverage area of UE C616 and UE D618 is outside the coverage area of UE B614, it is acceptable for UE B614 and UE C616 to reserve the same resources for the respective transmissions. Thus, such exposed node problems may lead to reduced resource utilization and to more serious resource conflicts with other UEs.

Fig. 6C shows an example of half duplex problem. In fig. 6C, if UE B624 sends a data packet to UE a 622 on some resources in a time slot, UE a 622 may not be able to receive such a transmission because UE a 622 may be sending to another UE (e.g., UE C626). This is a half duplex problem because, according to current standards, one device cannot transmit and receive on the same carrier. Another scenario for this problem is that when UE B624 sends a side uplink transmission, there is an uplink transmission of UE a 622 to the base station scheduled on the same time slot.

Fig. 6D shows an example of the continuous packet loss problem. In fig. 6D, two UEs have the same traffic period or the period of one UE is a multiple of the period of the other UE, and when the two UEs reserve the same resources, the initial collision is repeated, resulting in continuous packet loss (e.g., possibly caused by half duplex or hidden mode problems) until the resources are reselected.

In order to solve the above technical problems and improve reliability of the side uplink transmission, inter-UE cooperation may be considered, in which a UE (UE a) transmits cooperation information (e.g., a set of resources) to a transmitting UE (e.g., UE B) to assist the UE B in resource selection, thereby avoiding resource collision in the above scenario. The side-uplink enhanced work item in standardization of release 17 of 3GPP has agreed upon and encompasses inter-UE collaboration.

In release 17 (and the RANs 1#104-e conference), the three types of "resource sets" described by the work item description (RP-193257) have been agreed to be used for inter-UE collaboration in mode 2.

● Type a: UE a sends to UE B a set of resources preferred for UE B transmission (e.g., based on the sensing result of UE a).

● Type B: UE a sends to UE B a set of resources that are not preferred for UE B transmission (e.g., based on UE a's sensing results and/or expected/potential resource conflicts).

● Type C: UE a sends to UE B a set of resources for which a resource conflict is detected.

In release 17 (and the RANs 1#104b-e conference), release 17 was also agreed to support the following two inter-UE collaboration schemes.

● inter-UE cooperation scheme 1:

the collaboration information sent from UE a to UE B includes a set of resources that are preferred and/or non-preferred for UE B transmission.

■ The details to be studied (FFS) include the possibility to choose down between a preferred set of resources and a non-preferred set of resources, whether any additional information other than time/frequency indicating the resources within the set is included in the collaboration information,

■ One or more FFS conditions of scheme 1 are used.

● inter-UE cooperation scheme 2:

the collaboration information that UE a sends to UE B includes whether there is an expected/potential and/or detected resource conflict on the resources indicated by the SCI of UE B.

■ FFS details include the possibility to choose down between anticipated/potential conflicts and detected resource conflicts.

One or more FFS conditions of scheme 2 are used.

The present disclosure investigates inter-UE cooperation scheme 2. However, the described methods and designs may not be limited to scheme 2, and at least some methods and designs may be applied to inter-UE cooperation scheme 1 when appropriate (e.g., cooperation triggering/configuration).

In inter-UE cooperation scheme 2 for side-link, the cooperation information sent by UE a to UE B (UE B selects resources for side-link transmission) indicates whether there is an expected/potential and/or detected resource collision on the resources indicated by SCI of UE B. Then, UE B considers the cooperation information when selecting resources for its own transmission. The resource conflict may be due to another UE reserving the same resources (as in the case of the hidden node) or UE a (or another receiving UE) scheduling the same resources for its own transmissions.

As generally understood, scheme 1 differs from scheme 2 in that in scheme 2, the cooperating UE (e.g., UE a) generates the cooperation information after receiving the SCI for resource allocation from UE B (e.g., transmitting UE), whereas in scheme 1, the cooperation information is generated before receiving the SCI including side-uplink resource selection.

For scheme 2, one exemplary method is for UE a to send a 1-bit indicator to let UE B know if a collision (or possibly) has occurred. In scheme 2, a PSFCH or PSFCH-like channel may be used for collision indication.

The present disclosure provides an efficient design of resource allocation and mapping of PSFCH or PSFCH-like channels for collision indication, including how to allocate the time slot/subchannel/PRB set used by the PSFCH and which channel in the PSFCH PRB set to use for the cooperation information. PSFCH resource partitions are provided to avoid or reduce PSFCH collisions. A modified PSFCH format is provided for indicating a collision or carrying additional information.

In addition, the medium access control (medium access control, MAC) -control element (MAC control element, MAC-CE) may be used to carry cooperative information, which may be more flexible and may carry more information. The disclosure also provides a collaborative triggering manner.

As detailed below, the present disclosure provides efficient resource allocation and mapping rules for a PSFCH or PSFCH-like channel for collision indication, which may include:

● Efficient PSFCH association is achieved by one or a set of configurable parameters,

● A PSFCH selection offset is introduced in the PSFCH PRB set to handle potential PSFCH collisions,

● Resource association is specified by the association between the PSFCH and the virtual PSSCH, and most of the existing association rules are multiplexed.

As described in detail below, embodiments of the present disclosure also provide a modified PSFCH format or a new format for collision indication using a PSFCH, which may include:

● One or more states are added to the existing PSFCH format to carry collaboration information (e.g., collision indication, collision type, etc.),

● Using the new generic format of the existing PSFCH,

● Base sequence configurations are added to avoid collisions and/or to carry more bits.

The disclosed embodiments also provide techniques for transmitting cooperative information over a PSFCH or PSFCH-like channel in scheme 2 to avoid anticipated/potential collisions and detected collisions. The collaboration information may be 1 bit or 1 state in the mapping table of the PSFCH format that represents only the collision indication, or the collaboration information may be multiple bits for carrying the collision indicator and other collaboration information.

For the expected/potential collision, UE a may send the cooperative information such as the collision indication before transmitting the scheduled PSSCH, so that UE B may reselect the resources, avoiding the expected/potential collision. Thus, the collision indicator has no associated PSFCH resource. Resource allocation rules for the PSFCH or PSFCH-like channel that is used to transmit the collaboration information may be specified. An efficient method is provided for sub-channel and frequency allocation and PRB set allocation. Specific PSFCH allocations are described below.

Fig. 7 illustrates slot-subchannel assignments for PSFCH or PSFCH-like channels provided by some embodiments using the PSFCH associated with the originally scheduled PSSCH as a reference for cooperative information transmission.

Fig. 7 shows the use of SCI slot 700, where UE a acquires the scheduling resources of UE B and uses them as reference slots. As shown in fig. 7, UE a may be (pre) configured (e.g., predefined or configured by a base station) with one or more PSFCH slots 702 prior to a scheduled PSSCH transmission 704 to transmit the cooperation information. The configuration may be a value or set of values S ₁ ,S ₂ ,……,S _Ms Indicates a time slot difference between a reference time slot 706 (e.g., time slot 706 of a PSFCH associated with an initially scheduled PSSCH transmission 704), where M _s Is the maximum number of points in time at which the collaboration information is transmitted. Note that M _s Can be configured to be 1, or can be set to be 1 by default, which indicates that: only one slot with the PSFCH is configured to transmit the cooperation information, and UE B detects only the PSFCH for the cooperation information. Further, without losing generality, assume S ₁ <S ₂ <……<S _Ms . Although a strict inequality is used here, in the next subsection, if multiple PSFCHs are configured in one slot and combined for a joint set of resource indications, equality is also possible, i.e. S ₁ ≤S ₂ ≤……≤S _Ms 。

Assume that the PSFCH of the initially scheduled PSSCH 704 is at slot t ₀ 706, UE a may transmit via slot 702: t is t ₀ –S ₁ ,t ₀ –S ₂ ,……,t ₀ –S _Ms The PSFCH resource on one slot in (a) transmits the cooperation information. Since the PSFCH period is N, any two S _i The difference between the values must be a multiple of N, i.e. S _j –S _i =l×n, l is an integer. Due to S _j Is a timing offset indicating the time slot before the reference time slot 706 and can therefore be considered a timing advance parameter. In addition, to allow enough time for UE B to react to the cooperative information (e.g., sensing and resource reselection), it may be specified thatOr configure minimum S _min Or minimum timing advance for cooperative information and must be at time slot t ₀ –S _min The collaboration information or collision indication is previously or last sent from UE a. This results in S ₁ ≥S _min . Since reference slot 706 is a PSFCH slot and the slot indicated by the timing advance parameter is also a PSFCH slot, S _j Also a multiple of N. At this time { S } may not be arranged _j But is configured { s } _j ＝S _j Value of/N.

Fig. 8 illustrates alternative slot-subchannel assignments for PSFCH or PSFCH-like channels provided by some embodiments for cooperative information transmission. Fig. 8 shows the use of SCI slots 800, where UE a takes the resources scheduled by UE B and uses them as reference slots. As shown in FIG. 8, { S } 'may be specified' ₁ ,S′ ₂ ,……,S′ _Ms The set of values is used to indicate the slot difference from SCI transmission slot 800, where UE a receives the PSSCH resource reservation (i.e., SCI transmission) and uses it as a reference slot. Assume that the reference slot 800 for SCI transmission is t' ₀ UE a may pass through slot t' ₀ +S′ ₁ ,t′ ₀ +S′ ₂ ,……,t′ ₀ +S′ _Ms The PSFCH resource on one slot in (a) transmits the cooperation information. Although there may be no PSFCH on SCI slot 800, S 'may be adjusted' _i Such that time slot t' ₀ +S′ _j May be a time slot with a PSFCH. However, due to time slot t' ₀ Is dynamic, in order to configure time slot t 'on PSFCH time slots' ₀ +S′ _j ，S′ _j And also needs to be dynamic. However, in view of the large signal overhead, signaling { S 'in the physical layer (PHY)' _j There may be high costs. If S' _j With higher layer semi-static configuration, then time slot t' ₀ +S′ _j May not be a PSFCH slot. To address this problem, a rule may be specified such that each PSFCH slot 804 allocated for cooperative information transmission is a later but closest slot t' ₀ +S′ _j Is allocated to the PSFCH slot of (a). If enough sensing results are available for UE A, or UE A already knows some of UE A's schedulingTransmission (e.g., half duplex problem explained above), the following simple rule may be specified. After UE a receives the scheduling resources from UE B, UE a transmits the cooperation information such as the collision indication on the first available slot with the PSFCH. The sub-channels and PRB sets may be obtained by the same rules described below, and the associated PSFCHs in the PSFCH PRB sets may be obtained according to the rules/methods described below.

Alternatively, the sub-channel of the PSFCH carrying the cooperation information may be configured by an offset on the explicit sub-channel position or reference sub-channel, which may be, for example, a sub-channel of the PSFCH sub-channel or SCI associated with the initially scheduled PSSCH. For example, f ₀ Represented as a reference subchannel index. The subchannels of one or more PSFCHs for cooperation may be offset by a subchannel offset Δf ₁ ,……,Δf _Ms Specifying (i.e. (f) ₀ +Δf ₁ )％F _Tot ,……,(f ₀ +Δf _Ms )％F _Tot ) Wherein F is _Tot Is the total number of subchannels in the resource pool,% represents modulo arithmetic.

Once the subchannels and slots of the PSFCH are specified, certain PSFCH PRB sets may be specified for the PSFCH mapping as shown in fig. 5A and 5B. As also shown in fig. 5A and 5B, the PSFCH PRB set may be determined according to the PSSCH allocation. For transmission of the cooperation information, the PSFCH PRB set may be specified according to one of the following options:

● Based on timing advance setting (e.g., { S ₁ ,S ₂ ,……,S _Ms The cooperating PSFCH PRB set on the configured slots/subchannels may be the same as the set of PSFCH slots/subchannels of the initially scheduled PSSCH.

● Based on timing advance setting (e.g., { S ₁ ,S ₂ ,……,S _Ms }) may be determined according to the specific configuration of the higher layer or by dynamic signaling sent in the SCI.

Alternatively, a time window may be specified or (pre-) configured between the resource reservation slot and the initially scheduled TX PSSCH slot. After UE B transmits SCI for resource reservation information, UE B is inThe feedback channel for the collaboration information is monitored over a time window. UE a must transmit the cooperation information within the time window. The time window may be determined by reference to time slot t ₀ Two timing offsets S ₁ ^* And S is ₂ ^* Designation, i.e. [ t ] ₀ –S ₂ ^* ，t ₀ –S ₁ ^* ]. The association of feedback channels in the time domain for transmitting the cooperation information may be specified on each PSFCH slot within the time window. The sub-channel/PRB set positions can be deduced by the same principle as described above. The configured parameters may then be reduced to the lowest of the two parameters at the slot-only position.

Container for timing parameter settings: time slot timing advance { S } ₁ ,S ₂ ,……,S _Ms Or { S' ₁ ,S′ ₂ ,……,S′ _Ms The information may be configured by higher layers, e.g. by RRC parameter configuration or sent in SCI (especially second level SCI). If UE B sends a slot timing advance through SCI, the slot timing advance may be encapsulated in SCI including initial resource reservation. As well as the subchannel offset and/or PSFCH PRB set index, if desired.

Fig. 9 illustrates virtual PSSCH concepts of resource allocation for PSFCH or PSFCH-like channels for collaborative information transfer provided by some embodiments. Fig. 9 shows the use of SCI slots 900, where UE a takes the resources scheduled by UE B and uses them as reference slots. The above-described resource configuration or association of PSFCH or PSFCH-like channels for cooperation information may be interpreted using the virtual PSSCH concept. Since each PSFCH is associated with a particular PSSCH, the PSFCHs allocated for the cooperation information may be on the same set of PSFCH PRBs, or even on the same PSFCH associated with the PSSCH transmission. Thus, as shown in fig. 9, the slot and subchannel allocations for the cooperative PSFCH may be considered as a PSFCH associated with a mirrored or virtual PSSCH transmission 902 prior to the initially scheduled PSSCH 904. Thus, one or more PSFCHs for cooperation may be configured by scheduling the virtual PSSCH 902 using an existing SCI with a new bit for indicating that PSSCH resources are reserved for referencing a feedback channel for transmitting cooperation. Alternatively, PSFCH for collaboration The allocation may be configured by the timing advance of the virtual PSSCH 902 on the initially scheduled PSSCH 904 as the reference point, which may also be S _j Wherein j=1, … …, M _S . In addition, by the virtual PSSCH concept, the PSFCH PRB set may also be determined from the mapping between the PSFCH PRB set and the virtual PSSCH position in release 16 shown in fig. 5A and 5B. Thus, the process can be summarized as follows:

● Assume the slot index t of the initially reserved PSSCH 904 ₀ Then according to the configured timing advance S ₁ ,……,S _Ms Time slot 902 of virtual PSSCH is obtained: t is t ₀ –S ₁ ,t ₀ –S ₂ ,……,t ₀ –S _Ms ，

● The sub-channel of the virtual PSSCH 902 is acquired, similar to above, where the sub-channel may be aligned with the sub-channel of the reserved PSSCH, the sub-channel of the SCI, or the sub-channel of the reserved PSSCH, with an offset,

● The PSFCH PRB set of the virtual PSSCH 902 is obtained according to the same rule of the real PSSCH on the same resource.

Timing advance value S through virtual PSSCH configuration _j May be arbitrary, which means: in general, S _j Or S _j –S _i And need not be a multiple of the PSFCH period N. This feature facilitates high-level semi-static configuration. However, S may still be specified for simple PSFCH conflict management _j Or S _j –S _i Rules that are multiples of N.

According to the above embodiment, the process of UE B and UE a performing inter-UE cooperation through a feedback channel may be summarized in fig. 10. In the present disclosure, unless otherwise specified, UE a represents a cooperative UE (e.g., UE a in fig. 6A to 6C, or UE D in fig. 6B), and UE B represents a transmitting UE (e.g., UE B in fig. 6A to 6C, or UE C in fig. 6B). As shown in fig. 10, at the UE B end, in operation 1002, the UE B may transmit a resource reservation for a data packet in the SCI. In operation 1004, UE B may monitor the set of (pre) configured feedback channels in a (pre) configured time window to receive a collision indication from UE a. In operation 1006, UE B may receive a collision indication on the resources of the feedback channel. These resources may be associated with a resource reservation, a UE B ID, a UE a ID, and/or a type of collision indication. In operation 1008, UE B may reselect resources and transmit a SCI including scheduling information for the data packet, where the resources for the data packet may be selected according to the collision indication.

On the UE a side, in operation 1052, UE a may receive a resource reservation in SCI from UE B. In operation 1054, UE a may monitor and detect whether there is a collision on reserved resources indicated in the resource reservation of UE B within a (pre) configured time window. If a collision is detected, in operation 1056, UE a may select resources of the (pre) configured feedback channel according to UE B ID, UE a ID, resource pool, and/or type of collision observed on the resource reservation. In operation 1058, UE a may transmit a collision indication to UE B over the selected feedback channel according to the time window. If no collision is detected, in operation 1060, UE a does not transmit any content or may transmit a collision-free signal to UE B through the selected feedback channel according to the configuration or specification rules.

For the detected collision, UE a may transmit the cooperation information such as the collision indication after transmitting the scheduled PSSCH transmission. If the PSFCH can be overloaded with more information, the same PSFCH associated with PSSCH transmission can be used for collision indication. Embodiments of the present disclosure provide rules for the sub-channels and time slots or PRB sets of the PSFCH for cooperation information, which may be one of the following options.

● The sub-channels and time slots of the PSFCH for the cooperation information may be the same as those of the PSFCH associated with the transmitted PSSCH.

● The PRB set may be the same as the set of PSFCHs associated to the transmitted PSSCH.

● The PRB set may be located on a different time slot and/or a different subchannel with the PSFCH associated to the transmitted PSSCH, the different time slot or subchannel being defined by a (pre) configured timing offset parameter { S' ₁ ,S′ ₂ ,……,S′ _Ms And/or frequency offset parameters (Δf) ₁ ,Δf ₂ ,……,Δf _Ms And is indicated by the letter "x",wherein the PSFCH associated with the transmitted PSSCH is used as a reference point (e.g., the original PSFCH associated with the transmitted PSSCH).

● The location of a slot, sub-channel or PRB set may be indicated by configuring one or more virtual PSSCHs, where the virtual PSSCH may be indicated by SCI or timing offset value S 'on a reference resource' ₁ ,S′ ₂ ,……,S′ _Ms And/or frequency offset parameters (Δf) ₁ ,Δf ₂ ,……,Δf _Ms Dynamically configured, the reference resource may be an initially scheduled PSSCH.

Once the PSFCH PRB set is determined, one or more PSFCHs may be selected in the PRB set. As shown in fig. 5B and the following description, the index of the PSFCH in the PSFCH PRB set may be determined by:

j＝(T _ID +R _ID )mod L

l is the total number of resources in the PRB set, T _ID Is the layer 1ID of the transmitting UE (i.e., source ID in the second level SCI), R is for unicast ACK/NACK feedback or multicast option 1 NACK feedback only _ID ＝0。

For expected/potential collisions, regardless of how the sub-channel/slot/PRB set is determined as described above, once the PRB set is determined, the same rules as described above can be multiplexed to select the PSFCH. Fig. 11 illustrates the selection of PSFCHs among two PSFCH PRB sets provided by some embodiments. In FIG. 11, N _sub ＝2，M _S =5 PRBs/set. N (N) _CS =2. If the index is unchanged, the PSFCH of index j=7 is selected. If an offset of Δ=7 is included, PSFCH of index j=14 is selected. As shown in fig. 11, the PSFCH of index j=7 is selected for transmitting the cooperation information or the collision indicator. For expected/potential collisions, there is no explicit PSFCH collision if UE B does not transmit anything on the resources (e.g., considered virtual PSSCH) associated with the same PSFCH PRB set, since the location of the PSFCH in one or more PRB sets is related to the transmitting UE ID for unicast and multicast option 1. There may be a PSFCH collision with other UEs. But such PSFCH collision is opportunistic in that index j is determined by the transmit ID. Furthermore, motifs of different UEs or sidelines The columns may be different and thus the interference caused by the collision depends on the correlation between the two base sequences. However, if UE B occupies the exact same PSSCH resources as the virtual PSSCH resources for other transmissions, whether unicast or multicast and only NACK using HARQ option-1, then the exact same PSFCH resources may be selected if the same rules are multiplexed. PSFCH collisions may occur.

Similarly, for detected collisions, there are PSFCHs allocated for HARQ feedback in unicast and multicast transmissions. If there are no additional PSFCHs in the other slots/subchannels/PRB sets, then the collision will again occur.

To solve such collision problems or reduce interference, one of the following options may be considered:

(1) Using the modified PSFCH format,

(2) Using a different PSFCH sequence,

(3) Different PSFCHs are selected in the same PRB set.

Options (1) and (2) relate to the PSFCH format or definition described below. In option (3), a different PSFCH resource allocation is specified. An efficient approach is to add an offset in the following expression for the PSFCH index j:

j＝(T _ID +R _ID +Δ)mod L

the value of offset delta may be fixed, indicated by higher layer configuration or by physical layer signaling (e.g., SCI). As shown in fig. 11, when Δ=7, the PSFCH resource 14 is selected for the collaboration message.

As described above, if some or all of the rules and principles described in release 16 are multiplexed to allocate PSFCH resources to transmit cooperation information, there may be some PSFCH collisions. Another approach is to partition the PSFCH resources into two pools, one for HARQ ACK/NACK and the other for cooperative information transmission. Here, two PSFCH resource pool partitions, namely, a code domain partition and a frequency domain partition, are taken as an example.

For code domain partitioning, one common partitioning method may be that for SL PSFCH, the PRB set shares l=n _sub *M _S *N _CS The individual resources are used for PSSCH selection. Can specify a parameter L ₁ For partitioning resources into two PSFCH resource pools, one of size L ₁ Another size is L-L ₁ . Without loss of generality, the former L ₁ The PSFCH resources may be used for legacy HARQ feedback. Residual L-L ₁ The PSFCH resources may be used for collaboration messages such as collision indications. However, this arbitrary partitioning may create problems for legacy UE support, e.g., legacy UEs cannot be supported in multicast transmissions for release 17 transmitting UEs through this new PSFCH resource partitioning.

For the partitioning method that does not affect legacy UEs, it can be assumed that the PSFCH resource configuration for HARQ feedback is the same as before. PSFCH for HARQ may be from l=n _sub *M _S *N _CS And selecting from the resources. For transmitting a collaboration message such as a collision indication, the number of cyclic shift sets may be N' _CS >N _CS The new value is configured to expand the PSFCH resource pool. At this time, the total number of PSFCH resources increases from L to L' =n _sub *M _S *N′ _CS . At this time, additional L' -L resources may be used to allocate PSFCH for the collaboration message. Since legacy UE knows N _CS And therefore unaffected, and the PSFCH allocation is in the same pool as in release 16.

Fig. 12 illustrates PSFCH resource partitioning in the code domain provided by some embodiments. As shown in fig. 12, N _CS =2 is initially configured for HARQ feedback, with resource indices of 0 to 19. Then, N 'can be configured' _CS =3, so that more than 10 PSFCH resources (index 20 to 29) are available for the collaboration message.

To allocate the PSFCH for the collaboration message, the index j may be determined according to the following equation.

j＝L+((T _ID +R _ID +Δ)mod(L-L′)

N′ _cs The value of (2) may be arbitrarily selected from {2, … …,6}, as long as N' _CS >N _CS . To minimize standard impact, the values specified in release 16 (i.e., N 'can be multiplexed' _cs E {2,3,6 }) such that no new N is needed _CS The value specifies a cyclic shift index.

However, the aboveThe proposed method may not be applicable to the initially configured N _CS =6, because all resources are in the PSFCH pool for HARQ feedback.

For frequency domain partitioning, one common partitioning method may be to define M _PRB ＝N _sub *M _S . At this time, the PRB set shares l=n _sub *M _S ×N _CS ＝M _PRB *N _CS The PSFCH resources are used for PSFCH selection. Can specify the parameter M _PRB,1 For partitioning resources in the frequency domain into two PSFCH resource pools, one of size M _PRB,1 *N _CS Another size is (M _PRB –M _PRB,1 )*N _CS . One part of the resource pool can be used for HARQ feedback, and the other part of the resource pool can be used for cooperative messages such as conflict indication and the like. Also, such partitioning may present problems in supporting legacy UEs.

In order to partition without affecting legacy UEs, a method is provided herein that does not affect legacy UEs. As described above, when the PSSCH is allocated with resources on a plurality of sub-channels (i.e., N _sub >1) When, PSFCH selection may be performed using multiple PRB sets on different subchannels. However, an alternative option described in release 16 is that the PSFCH may select from one PRB set on the starting subchannel of the PSSCH. According to this feature, N _sub >The resources in case 1 may be partitioned as shown in fig. 13. Fig. 13 illustrates PSFCH resource partitioning in the frequency domain provided by some embodiments. The UE is configured with a PSFCH selected from one PRB set aligned with the starting subchannel of the PSSCH for HARQ feedback. Other PSFCH resources may then be used for PSFCH allocation to send the collaboration information. The PSFCH channel index for cooperation can be obtained according to the following equation.

j＝M _s *N _CS +((T _ID +R _ID +Δ)mod((N _sub -1)*Mx*N _CS )

In the above equation, Δ may be set to 0 or some other value in combination with the method proposed above. As shown in fig. 12, the PSFCH index j may be one of {10, … …,19} in the PRB set.

For use for initial schedulingIf N _sub >1, the disclosed technique performs well. For both expected/potential conflicts and detected conflicts, one can determine the conflict by specifying N _sub >1, regardless of the subchannel size of the initially scheduled PSSCH.

For the modified PSFCH format with single-state/1-bit feedback, for ACK/NACK feedback, 1-bit information or two states (ACK and NACK) may be represented by two cyclic shifts of the sequence. In the exemplary modified PSFCH format, a state, i.e., a "collision" or "NACK-collision" state, may be added to indicate an expected/potential collision or detected collision.

Since the ACK/NACK messages are represented by different cyclic shifts of the same sequence, the new NACK-collision status may also be represented by another collision shift C ₁ Indicating that the collision shift is different from that for ACK/NACK, as shown in Table 1, C ₁ Not equal to 0 or 6. On the other hand, if the same base sequence is used, C can be selected ₁ To avoid collisions with other PSFCHs on the same PRB resource represented by different cyclic shifts.

Since the length of the sequence is 12, the total number of cyclic shifts is 12, including shift 0. As shown in Table 16.3-1 of TS 38.213, when N _CS When=6, all 12 cyclic shifts are used for ACK/NACK transmission. Additional cyclic shifts cannot be used to indicate collisions. However, when N _CS When=1, 2, 3, some unused cyclic shifts may be used to represent the NACK-collision state. Can be N of each kind _CS Configuration specification C ₁ Values. By examining the cyclic shift index in table 16.3-1 of TS 38.213 in the existing table, for all three N _CS Configuration, one C may be selected from {1,5,7, 11} ₁ Values.

Table 1: modified PSFCH mapping for HARQ ACK/NACK with collision indication

HARQ-ACK values	0(NACK)	1(ACK)	2 (NACK-collision)
				Cyclic shift of sequences	0	6	C ₁

Similarly, for HARQ option 1 with NACK only, a state may also be added, such as with cyclic shift C ₂ Is shown in table 2 of (c).

Table 2: modified PSFCH mapping for HARQ NACK-only with collision indication

HARQ-ACK values	0(NACK)	1(ACK)	2 (NACK-collision)
				Cyclic shift of sequences	0	N/A	C ₂

When the use of the modified PSFCH format is indicated for a detected collision, the same PSFCH resource allocation can be multiplexed without any change. UE B may detect the PSFCH to see if there is a collision. Furthermore, if a modified PSFCH is used, triggering of inter-UE cooperation may be omitted, since the UE may always detect the PSFCH from the modified PSFCH format for the incoming NACK-collision. However, for UEs that do not require cooperation, the present embodiment may unnecessarily increase complexity.

For PSFCH channel allocation, the PSFCH format is not changed, but rather the PSFCH may be allocated by using the same HARQ ACK/NACK mapping format for collision indication or transmitting cooperation information in general. In order to carry 1 bit of information, a PSFCH channel allocation is required. One of the states (i.e., ACK or NACK state) may be used for collision indication. For expected/potential collisions or detected collisions, PSFCH channel allocations for cooperative information are described in this disclosure.

For the modified PSFCH format with multi-state/multi-bit feedback, note that for the modified ACK/NACK after adding one cyclic shift for NACK-collision state, as shown in Table 1, when N _CS When=1, 2, and 3, the cyclic indexes 9, 6, and 3 remain unused. More states may be added to the table to carry more information. When N is _CS When=1, 2 and 3, additional states 9, 3 and 1 may be added. As shown by way of example in table 3, more states (additional states 1, 2, 3, … …) may be included in the table, including one state for conflict indication. Each state is represented using a cyclic shift. In addition to the collision indication, additional information such as the type of collision described in this disclosure may be included in the feedback.

Table 3: modified PSFCH mapping for HARQ ACK/NACK with collision indication

Similarly, for HARQ only NACK PSFCH, table 2 can be extended by adding more states in the PSFCH format, as shown in table 4 below.

Table 4: modified PSFCH mapping for HARQ NACK-only with collision indication

For PSFCH channel allocation, the same PSFCH format carrying 1-bit/2-state information in each PSFCH may be used to transmit the cooperation information. For multi-bit feedback, more than one PSFCH is allocated as described in this disclosure.

For PSFCH channel allocations with a modified PSFCH format, if a dedicated PSFCH is allocated for cooperation, as described in this disclosure, the information mapping of the PSFCH may be redefined to carry cooperation information including a collision indication. As shown in table 5, a mapping table of 2 bits/4 states may be provided, each state may be represented using a cyclic shift. Without loss of generality, state 1 may represent a collision indication.

Table 5: modified PSFCH mapping of collaboration information (2 bits/4 states)

Status value	State 1 (NACK-collision)	State 2	State 3	State 4
					Bit value	(b ₁ ,b ₂ )＝(0,0)	(b ₁ ,b ₂ )＝(1,0)	(b ₁ ,b ₂ )＝(0,1)	(b ₁ ,b ₂ )＝(1,1)
Cyclic shift of sequences	C _3,1	C _3,2	C _3,3	C _3,4

As shown herein, PSFCH channel allocation for a 1-bit message for collision indication is a special case of this approach. The mapping of ACK/NACKs may be multiplexed to represent states 1 and 2 to carry some kind of cooperation information (e.g., collision indication).

For PSFCH sequence configuration, both the messages carried in the PSFCH and the PSFCH multiplexing are achieved by different cyclic shifts of the base sequence. NR designates a total of 30 base sequences of length 12. Using the same first base sequence configured as u=0, or using u=n _ID A base sequence of mod 30, wherein n _ID Configured by the upper layer parameter sl-PSFCH-HopID. Thus, for the PSFCH or PSFCH-like channel used for the collaboration message, another sl-PSFCH-HopID, which may be referred to as sl-PSFCH-HopID-Coord, may be configured. The new sl-PSFCH-HopID-chord may be configured alone at the upper layer or specified using an offset on the original sl-PSFCH-HopID configured for HARQ feedback (i.e., sl-PSFCH-HopID-chord=sl-PSFCH-hopid+Δ) _HopID )。+Δ _HopID The value of (2) may be a fixed value or may be configured in an upper layer.

The collision indication for collaboration information carried in a container with 1 bit of information or just one state is described above. Also as described above, more collaboration information may be carried in the PSFCH or PSFCH-like channel.

The collision type indication included in the cooperation information may help UE B avoid further collisions in resource re-selection. Among all collision types, half duplex induced collisions may be one example of information for resource reselection in the event of an expected/potential collision. For half duplex problems, the entire time slot of UE a or receiving UE for UE B's scheduling PSSCH may be excluded from resource reselection. If UE B does not know the type of collision, when UE B performs a resource reselection after receiving the collision indication, UE B may select resources on the same time slot as the initially reserved resources, thereby generating a new collision. Thus, it may be better to include an indication of half-duplex collisions in the collaboration information using the multi-state/multi-bit feedback method described above.

In addition, the time slots scheduled for the transmission of UE a may be included in the collaboration message sent to UE B.

When PSSCH uses resources on multiple sub-channels for scheduling, not every sub-channel will collide unless it is a half-duplex collision. Then, a subchannel indicating that a collision was detected may avoid unnecessary resource reselection. No colliding sub-channels may still be used for PSSCH transmission. The new SCI may be sent to reserve these subchannels using the new modulation and coding scheme, and so on. The additional information for each sub-channel collision indication may be transmitted using the multi-state/multi-bit feedback method described above.

When a PSFCH or PSFCH-like channel is used to transmit a collision indication or other cooperation information, there may be a collision due to the PSFCH being transmitted and/or received simultaneously on the same time slot. Such collision also occurs with the PSFCH used for HARQ feedback. In release 16, to resolve this collision, the UE transmits HARQ feedback according to the priority order of transmitting data in the PSSCH. To resolve conflicts with PSFCH or PSFCH-like channels for collaboration, the exemplary technique may assign a priority value for the PSFCH or PSFCH-like channel carrying collaboration information by one of the following options:

● The same priority as the priority associated with the scheduled PSSCH or transmitted PSSCH is assigned,

● A new priority is assigned on the PSFCH, where the priority may be indicated by a higher layer semi-static configuration or in the SCI for the original PSSCH.

In addition to the PSFCH or PSFCH-like channel, the cooperation information may be transmitted through the MAC-CE. The MAC-CE may transmit on the PSSCH. The message size or number of information bits carried in the MAC-CE is much larger than the PHY signal. More information may be sent to UE B. In addition to collision indication, the additional information described in this disclosure may also be easily carried in the MAC-CE.

For example, a bitmap for a subchannel collision may be included in the MAC-CE for a collision indication for each subchannel.

However, since the MAC-CE transmits in the PSSCH, additional sensing, PSSCH resource selection and transmission may be required, which may also occur some collisions.

In addition to the collision indication, UE a may also send a preferred set of resources and/or a non-preferred set of resources to UE B in the macce for UE B to perform resource reselection (i.e., both scheme 1 and scheme 2 may be). UE a may also select a resource and signal the resource to UE B through the MAC CE. Depending on the configuration or properties of UE a and B (e.g., fleet lead and end trucks in truck fleet scenarios) or the operation or use of the collaboration information by UE B (e.g., fully following the collaboration information of UE a), UE B may use it as a resource reservation for data packet transmission. In this case, more like UE B transmitting using UE a's side-uplink grant, UE a performs re-evaluation/preemption on UE B after UE B selects resources.

Since the transmission of MAC-CEs is typically delayed more than PHY signals, it may be desirable to specify timing requirements. Fig. 14 illustrates exemplary collaboration information in a MAC-CE provided by some embodiments. As shown in fig. 14, the expiration 1402 of the collision indication and other cooperation information transmitted in the MAC-CE may be designated as the expiration of the transmitting MAC-CE by a timing advance slot offset 1404 from the initially scheduled transmitting PSSCH slot 1406 for the intended/potential collision. For a detected collision, a maximum delay 1408 after the scheduled PSSCH 1410 is transmitted may be specified so that a collision indication can be received in time. Such a maximum delay may be designated as a packet delay budget for transmitting the collaboration information.

Can replaceThe deadline may be, in turn, by a delay bound (i.e., the maximum delay S after UE B sends the SCI using the resources selected for PSSCH _LB ) To specify. Such delay bound may be sent from UE B to UE a (e.g., via PC 5-RRC). Suppose UE B is at t ₀ SCI is sent up, then UE a sends a message at the delay bound (i.e., t ₀ +S _LB ) The cooperation information including the collision indication is previously transmitted, which may be configured by a higher layer or transmitted by the UE B in the PHY through the SCI (e.g., the same SCI transmitted for resource reservation).

For the joint PSFCH and MAC CE for the cooperation information, note that the PFSCH and MAC CE may both be used for the cooperation information in the same UE B resource selection procedure. In general, when the PSFCH and the MAC CE are used together for cooperation of the same UE B resource selection procedure, cooperation information may be split and carried by the PSFCH and the MAC CE, respectively. SCI for resource reservation sent by UE B may be used to support cooperative feedback.

For example, the PSFCH may be used for collision indication and an indication that the MAC CE carries additional cooperation information for the same UE B resource selection procedure. The cooperation information may be a collision type, a preferred set of resources, a non-preferred set of resources, or a preferred set of resources for a side-link grant in case one or more resources of UE B are to be used for its transmission resource selection (reselection) based on the received cooperation information only.

Similar to the MAC CE, the cooperation information may be transmitted via the PHY signal SCI, including a collision indication and/or a preferred or non-preferred set of resources. The maximum delay or delay bound may be specified for the collaboration information carried by the SCI that UE a sends to UE B, which may be configured at a higher layer. Such delay bound may be sent from UE B to UE a (e.g., via PC 5-RRC). At UE B at t ₀ After sending the SCI, UE a may then send a message at a configured delay bound (e.g., t ₀ +S _LB ) The cooperation information including the collision indication is previously transmitted, which may be configured by a higher layer or transmitted by the UE B in the PHY through the SCI (e.g., the same SCI transmitted for resource reservation).

In addition to the collision indication, UE a may also send a preferred set of resources and/or a non-preferred set of resources to UE B using SCI for UE B to perform resource reselection (i.e., both scheme 1 and scheme 2 may be used). UE a may also select a resource and signal the resource to UE B through the SCI. The resources used by UE B for its transmission resource selection (reselection) may be based solely on the received cooperation information, and SCI for coordinated feedback from UE a to UE B may carry the selected resources as a preferred set of resources for UE B, depending on the configuration or properties of UE a and UE B, or the operation or use of the cooperation information by UE B. UE B may then use it as a resource reservation for data packet transmissions. In this case, UE a uses SCI as the cooperative information feedback, wherein the feedback includes reserved resources as SL grant for UE B so that UE B can reserve resources of UE a for transmission. This can be seen as UE a performing re-evaluation/preemption of UE B after UE B selects resources.

Although the modified PSFCH format is employed, there may be no need to trigger or configure inter-UE cooperation, as the collision indication carried in the modified PSFCH may act as an implicit cooperation trigger. However, in case of explicit triggers or higher layers being configured, the configured UE B may desire to send out some cooperation information from UE a. Collaboration may be triggered by one of the following options.

● UE B may explicitly trigger cooperation using the SCI signal (e.g., by reserving bits using SCI format 1). SCI sent by UE B for initial resource reservation may be used to support a trigger and/or an indicated/activated cooperative feedback including one or more of the following: for example, PSFCH, MAC CE, PSFCH+MAC CE, SCI, PSFCH+MAC CE, and so forth.

● inter-UE cooperation may be determined by higher layer configuration (e.g., activation/deactivation without explicit triggering).

● The cooperation may be triggered and initiated by the UE a when certain conditions are met.

Fig. 15A illustrates a flow chart of a method 1500 for inter-UE collaboration in SL communication, provided by some embodiments. The method 1500 may be implemented or performed by a first UE (e.g., UE a). The method 1500 may also be implemented or performed by routines, subroutines, or software modules executed by one or more processing units. The method 1500 may also be implemented or performed by hardware, software, or a combination of hardware and software. It is fully within the scope of the present disclosure for one of ordinary skill in the art to encode software for implementing or performing the method 1500. The method 1500 may include more or fewer operations than those shown and described, and may be implemented or performed in a different order. The computer readable code or instructions of the software executable by the one or more processing units may be stored in a non-transitory computer readable medium, for example, in a memory of the first UE.

The method 1500 begins at operation 1502: the first UE (e.g., UE a) receives side uplink control information (sidelink control information, SCI) from a second UE (e.g., UE B) in a first time slot. The SCI includes resource reservation of a shared channel. The resource reservation indicates a set of frequency resources and a time resource allocation. In operation 1504, the first UE transmits a collision indicator to the second UE on a resource of a feedback channel. The resources of the feedback channel include a second time slot for transmitting the collision indicator. The location of the second time slot is based on one of the following time slots: the first time slot or the time slot indicated by the time resource allocation. The conflict indicator indicates a potential resource conflict or a detected resource conflict on at least one of the following objects: a set of frequency resources of the resource reservation indication or a time resource allocation of the resource reservation indication.

In some embodiments, the collision indicator may indicate a sensed-based potential resource collision on the time resource allocation or a detected resource collision on the time resource allocation, or the collision indicator may indicate a sensed-based potential resource collision on the set of frequency resources or a detected resource collision on the set of frequency resources. In some embodiments, the location of the second time slot may be immediately after the first time slot plus a time interval. In some embodiments, the location of the second time slot may be the shortest time before the time slot of the time resource allocation indication. In some embodiments, the location of the second time slot based on one of the first time slot or the time slot indicated by the time resource allocation may be configured by a base station or predefined. In some embodiments, the first UE may be a destination of the shared channel transmitted from the second UE. In some embodiments, the feedback channel may be a physical side uplink feedback channel (physical sidelink feedback channel, PFSCH). In some embodiments, the enablement of transmitting the collision indicator may be configured by higher layer signaling. In some embodiments, the SCI may further include 1-bit information indicating that the second UE is capable of receiving the collision indicator from the first UE. In some embodiments, the SCI may include fewer reserved bits when the second UE is to transmit the 1-bit information. In some embodiments, the first UE may monitor a set of frequency resources indicated by the time resource allocation in the SCI. In some embodiments, the feedback channel may include a first set of resources and a second set of resources. The first set of resources may carry an Acknowledgement (ACK) or a Negative ACK (NACK) for a received shared channel, and the second set of resources may include resources of the feedback channel carrying the collision indicator. In some embodiments, the first set of resources and the second set of resources may be located on different frequency resources. In some embodiments, the first UE may send the collision indicator to the second UE according to a priority indicated in the SCI.

Fig. 15B illustrates a flow chart of a method 1550 provided by some embodiments for inter-UE collaboration in SL communication. Method 1550 may be implemented or performed by a second UE (e.g., UE B). Method 1550 may also be implemented or performed by routines, subroutines, or software modules executed by one or more processing units. The method 1550 may also be implemented or performed by hardware, software, or a combination of hardware and software. It is well within the scope of the present disclosure for one of ordinary skill in the art to encode software for implementing or performing the method 1550. Method 1550 may include more or fewer operations than those shown and described and may be implemented or performed in a different order. The computer readable code or instructions of the software executable by the one or more processing units may be stored in a non-transitory computer readable medium, for example, in a memory of the second UE.

Method 1550 begins at operation 1552: the second UE (e.g., UE B) transmits side uplink control information (sidelink control information, SCI) to the first UE (e.g., UE a) in a first time slot. The resource reservation indicates a set of frequency resources and a time resource allocation. In operation 1554, the second UE receives a collision indicator from the first UE on a resource of a feedback channel. The resources of the feedback channel include a second time slot for receiving the collision indicator. The location of the second time slot is based on one of the following time slots: the first time slot or the time slot indicated by the time resource allocation. The conflict indicator indicates a potential resource conflict or a detected resource conflict on at least one of the following objects: a set of frequency resources of the resource reservation indication or a time resource allocation of the resource reservation indication.

In some embodiments, the collision indicator may indicate a sensed-based potential resource collision on the time resource allocation or a detected resource collision on the time resource allocation, or the collision indicator may indicate a sensed-based potential resource collision on the set of frequency resources or a detected resource collision on the set of frequency resources. In some embodiments, the location of the second time slot may be immediately after the first time slot plus a time interval. In some embodiments, the location of the second time slot may be the shortest time before the time slot of the time resource allocation indication. In some embodiments, the location of the second time slot based on one of the first time slot or the time slot indicated by the time resource allocation may be configured by a base station or predefined. In some embodiments, the first UE may be a destination of the shared channel transmitted from the second UE. In some embodiments, the feedback channel may be a physical side uplink feedback channel (physical sidelink feedback channel, PFSCH). In some embodiments, the enablement of receiving the collision indicator may be configured by higher layer signaling. In some embodiments, the SCI may further include 1-bit information indicating that the second UE is capable of receiving the collision indicator from the first UE. In some embodiments, the SCI may include fewer reserved bits when the second UE is to transmit the 1-bit information. In some embodiments, the feedback channel includes a first set of resources that may carry an Acknowledgement (ACK) or a Negative ACK (NACK) for a received shared channel and a second set of resources that may include resources of the feedback channel that carry the collision indicator. In some embodiments, the first set of resources and the second set of resources may be located on different frequency resources. In some embodiments, the second UE may receive the collision indicator from the first UE according to a priority indicated in the SCI.

Fig. 16 is a schematic diagram of an exemplary communication system 1600. In general, the system 1600 enables multiple wireless or wireline users to send and receive data and other content. System 1600 can implement one or more channel access methods, such as code division multiple access (code division multiple access, CDMA), time division multiple access (time division multiple access, TDMA), frequency division multiple access (frequency division multiple access, FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), or non-orthogonal multiple access (NOMA).

In this example, communication system 1600 includes electronic devices (electronic device, ED) 1610 a-1610 c, radio access networks (radio access network, RAN) 1620 a-1620 b, core network 1630, public switched telephone network (public switched telephone network, PSTN) 1640, internet 1650, and other networks 1660. Although fig. 16 illustrates a number of these components or units, any number of these components or units may be included in system 1600.

ED 1610a through 1610c are used to operate or communicate in system 1600. For example, ED 1610a to 1610c are used for transmission or reception through a wireless communication channel or a wired communication channel. Each ED 1610 a-1610 c represents any suitable end-user device and may include the following devices (or may be referred to as): a User Equipment (UE), a wireless transmit or receive unit (wireless transmit or receive unit, WTRU), a mobile station, a fixed or mobile subscriber unit, a cellular telephone, a personal digital assistant (personal digital assistant, PDA), a smart phone, a notebook computer, a touch pad, a wireless sensor, or a consumer electronic device.

The RANs 1620 a-1620 b here include base stations 1670 a-1670 b, respectively. Base stations 1670 a-1670 b are each used to wirelessly connect with one or more EDs 1610 a-1610 c to enable access to a core network 1630, PSTN 1640, internet 1650, or other network 1660. For example, the base stations 1670 a-1670B may include (or may be) one or more of several well-known devices, such as a base transceiver station (base transceiver station, BTS), a node B (NodeB), an evolved NodeB (eNodeB), a Next Generation (NG) NodeB (NG NodeB, gNB), a Home NodeB (Home NodeB), a Home eNodeB, a site controller, an Access Point (AP), or a wireless router. ED 1610 a-1610 c are used to connect and communicate with the Internet 1650 and may access the core network 1630, PSTN 1640, or other networks 1660.

In the embodiment illustrated in fig. 16, base station 1670a forms part of RAN 1620a and RAN 1620a may include other base stations, units, and/or devices. Likewise, the base station 1670b forms part of the RAN 1620b, and the RAN 1620b may include other base stations, units, or devices. Base stations 1670a through 1670b each transmit and/or receive wireless signals within a particular geographic area or region (sometimes referred to as a "cell"). In some embodiments, multiple-input multiple-output (MIMO) technology may be employed such that multiple transceivers are used for each cell.

Base stations 1670 a-1670 b communicate with one or more EDs 1610 a-1610 c over one or more air interfaces 1690 using a wireless communication link. Air interface 1690 may utilize any suitable radio access technology.

It is contemplated that system 1600 may employ multi-channel access functionality, including the schemes described above. In a specific embodiment, the base station and ED implement a 5G New Radio (NR), LTE-A or LTE-B. Of course, other multiple access schemes and wireless protocols may be used.

RANs 1620a and 1620b communicate with core network 1630 to provide voice, data, applications, voice over internet protocol (Voice over Internet Protocol, voIP) or other services to EDs 1610 a-1610 c. It is to be appreciated that the RANs 1620 a-1620 b or core network 1630 can communicate directly or indirectly with one or more other RANs (not shown). The core network 1630 may also serve as gateway access to other networks (e.g., PSTN 1640, internet 1650, and other networks 1660). In addition, some or all of EDs 1610 a-1610 c may include functionality to communicate with different wireless networks over different wireless links using different wireless technologies or protocols. Instead of (or in addition to) wireless communication, the ED may communicate with a service provider or switch (not shown) and with the Internet 1650 via a wired communication channel.

Although fig. 16 shows one example of a communication system, various modifications may be made to fig. 16. For example, communication system 1600 may include any number of EDs, base stations, networks, or other components in any suitable configuration.

17A and 17B illustrate exemplary devices that may implement the methods and guidance provided by the present disclosure. Specifically, fig. 17A shows an exemplary end device (ED/terminal device) 1710, and fig. 17B shows an exemplary base station 1770. These components may be used in system 1600 or any other suitable system.

As shown in fig. 17A, ED 1710 includes at least one processing unit 1700. The processing unit 1700 implements various processing operations of the ED 1710. For example, processing unit 1700 may perform signal encoding, data processing, power control, input/output processing, or any other function that enables ED 1710 to operate in system 1600. The processing unit 1700 also supports the methods and guidelines described in detail above. Each processing unit 1700 includes any suitable processing device or computing device for performing one or more operations. For example, each processing unit 1700 may include a microprocessor, microcontroller, digital signal processor, field programmable gate array, or application specific integrated circuit.

ED 1710 also includes at least one transceiver 1702. The transceiver 1702 is used to modulate data or other content for transmission through at least one antenna or network interface controller (Network Interface Controller, NIC) 1704. The transceiver 1702 is also operable to demodulate data or other content received via the at least one antenna 1704. Each transceiver 1702 includes any suitable structure for generating signals for wireless transmission or wired transmission or for processing signals received wirelessly or by wire. Each antenna 1704 includes any suitable structure for transmitting or receiving a wireless or wired signal 1790. One or more transceivers 1702 may be used in ED 1710, and one or more antennas 1704 may be used in ED 1710. Although the transceiver 1702 is shown as a separate functional unit, the transceiver 1702 may also be implemented using at least one transmitter and at least one separate receiver.

ED 1710 also includes one or more input/output devices 1706 or interfaces (e.g., a wired interface to the Internet 1650). The input/output devices 1706 support interactions with users or other devices in the network (network communications). Each input/output device 1706 includes any suitable structure for providing information to or receiving information from a user, such as a speaker, microphone, keypad, keyboard, display, or touch screen, including network interface communications.

In addition, ED 1710 includes at least one memory 1708. Memory 1708 stores instructions and data used, generated, or collected by ED 1710. For example, the memory 1708 may store software instructions or firmware instructions that are executed by the one or more processing units 1700, as well as data for implementing the exemplary methods. Each memory 1708 includes any suitable volatile or nonvolatile storage and retrieval device or devices. Any suitable type of memory may be used, such as random access memory (random access memory, RAM), read Only Memory (ROM), hard disk, optical disk, subscriber identity module (subscriber identity module, SIM) card, memory stick, secure Digital (SD) memory card, etc.

As shown in fig. 17B, the base station 1770 includes at least one processing unit 1750, at least one transceiver 1752 including functions of a transmitter and a receiver, one or more antennas 1756, at least one memory 1758, and one or more input/output devices or interfaces 1766. The scheduler is coupled to processing unit 1750 as will be appreciated by those skilled in the art. The scheduler may be included in the base station 1770 or may operate separately from the base station 1770. The processing unit 1750 performs various processing operations for the base station 1770, such as signal coding, data processing, power control, input/output processing, or any other function. Processing unit 1750 may also support the methods and guidelines detailed above. Each processing unit 1750 comprises any suitable processing device or computing device for performing one or more operations. For example, each processing unit 1750 may comprise a microprocessor, a microcontroller, a digital signal processor, a field programmable gate array, or an application specific integrated circuit.

Each transceiver 1752 includes any suitable structure for generating signals for wireless or wired transmission to one or more EDs or other devices. Each transceiver 1752 also includes any suitable structure for processing signals received from one or more EDs or other devices, either wirelessly or by wire. Although the transmitter and receiver are shown combined into transceiver 1752, the transmitter and receiver may be separate components. Each antenna 1756 comprises any suitable structure for transmitting or receiving wireless or wired signals 1790. Although a common antenna 1756 is shown here as being coupled to the transceivers 1752, one or more antennas 1756 may be coupled to one or more transceivers 1752 such that when the transmitter and receiver are configured as separate components, separate antennas 1756 may be coupled to the transmitter and receiver. Each memory 1758 includes any suitable volatile or nonvolatile storage and retrieval device or devices. Each input/output device 1766 supports interaction with users or other devices in the network (network communications). Each input/output device 1766 includes any suitable structure for providing information to or receiving/providing information from a user, including network interface communications.

Fig. 18 is a block diagram of a computing system 1800 that may be used to implement the devices and methods disclosed herein. For example, the computing system may be any entity in a UE, access Network (AN), mobility management (mobility management, MM), session management (session management, SM), user plane gateway (user plane gateway, UPGW), or Access Stratum (AS). A particular device may use all or only a subset of the components shown, and the level of integration may vary from device to device. Moreover, an apparatus may include multiple instances of components, e.g., multiple processing units, multiple processors, multiple memories, a sender, multiple receivers, etc. The computing system 1800 includes a processing unit 1802. The processing unit includes a central processing unit (central processing unit, CPU) 1814, a memory 1808, and may also include a mass storage device 1804, video adapter 1810, and I/O interface 1812 connected to bus 1820.

Bus 1820 may be one or more of any type of several bus architectures including a memory bus or memory controller, a peripheral bus, or a video bus. CPU 1814 may include any type of electronic data processor. The memory 1808 may include any type of non-transitory system memory, such as static random access memory (static random access memory, SRAM), dynamic random access memory (dynamic random access memory, DRAM), synchronous DRAM (SDRAM), read-only memory (ROM), or a combination thereof. In one embodiment, memory 1808 may include ROM for use at startup and DRAM for storing programs and data for use when executing programs. The memory 1808 may include instructions executable by the processing unit 1802.

The mass memory 1804 may include any type of non-transitory storage device for storing and making accessible via the bus 1820 data, programs, and other information. For example, mass memory 1804 may include one or more of a solid state disk, hard drive, magnetic disk drive, or optical disk drive.

The video adapter 1810 and the I/O interface 1812 provide an interface to couple external input and output devices to the processing unit 1802. As shown, examples of input and output devices include a display 1818 coupled to video adapter 1810 and a mouse, keyboard, or printer 1816 coupled to I/O interface 1812. Other devices may be coupled to the processing unit 1802 and additional or fewer interface cards may be used. For example, a serial interface such as a universal serial bus (universal serial bus, USB) (not shown) may be used to provide an interface for external devices.

The processing unit 1802 also includes one or more network interfaces 1806, which may include a wired link, e.g., an ethernet cable, or a wireless link to an access node or a different network. The network interface 1806 enables the processing unit 1802 to communicate with remote units over a network. For example, the network interface 1806 may provide wireless communication via one or more transmitter/transmit antennas and one or more receiver/receive antennas. In one embodiment, the processing unit 1802 is coupled to a local area network 1822 or wide area network for data processing and communication with other processing units, the Internet, or remote storage facilities, among other remote devices.

In some embodiments, computing system 1800 may include means for implementing embodiments of the disclosure. The processing unit 1802 may execute instructions stored in the memory 1808 to cause the apparatus to perform exemplary methods of the present disclosure.

All or part of the embodiments described above may be implemented by software, hardware, firmware, or any combination thereof. When software is used for implementation, the embodiments may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or a portion of the processes or functions will be generated in accordance with embodiments of the present disclosure. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. Computer instructions may be stored in a computer-readable storage medium or may be transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by a wired means (e.g., coaxial cable, fiber optic, or digital subscriber line), or wireless means (e.g., infrared, microwave, etc.). Computer-readable non-transitory media include all types of computer-readable media, including magnetic storage media, optical storage media, flash memory media, or solid-state storage media.

It should be understood that one or more steps of the embodiment methods provided herein may be performed by the corresponding units or modules. For example, the signal may be transmitted by a transmitting unit or a transmitting module. The signal may be received by a receiving unit or a receiving module. The signals may be processed by a processing unit or processing module. Other steps may be performed by the determining unit/module, the obtaining unit/module, the priority updating unit/module, the indicating unit/module, the resource selecting unit/module, the resource pool partitioning unit/module, the re-evaluating unit/module, the preemption unit/module, the resource reservation unit/module, and/or the priority mapping unit/module. The corresponding units or modules may be hardware, software or a combination thereof. For example, one or more of the units or modules may be an integrated circuit, such as a field programmable gate array (field programmable gate array, FPGA) or an application-specific integrated circuit (ASIC).

Although the present specification has been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims. Furthermore, the scope of the present disclosure is not limited to the particular embodiments described herein, as one of ordinary skill in the art will readily appreciate from the present disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein. Accordingly, it is the object of the appended claims to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

1. A method, comprising:

a first User Equipment (UE) receiving a side uplink control information (SCI) from a second UE in a first time slot, wherein the SCI comprises a resource reservation of a shared channel, the resource reservation indicating a set of frequency resources and a time resource allocation;

the first UE sends a collision indicator to the second UE on the resources of the feedback channel,

wherein the resources of the feedback channel include a second time slot for transmitting the collision indicator, the location of the second time slot being based on one of the following time slots: the first time slot or the time slot indicated by the time resource allocation,

the conflict indicator indicates a potential resource conflict or a detected resource conflict on at least one of the following objects: a set of frequency resources of the resource reservation indication or a time resource allocation of the resource reservation indication.

2. The method of claim 1, wherein the collision indicator indicates a sensing-based potential resource collision on the time resource allocation or a detected resource collision on the time resource allocation, or

The collision indicator indicates a sensing-based potential resource collision on the set of frequency resources or a detected resource collision on the set of frequency resources.

3. The method of claim 1, wherein the second time slot is located immediately after the first time slot plus a time interval.

4. The method of claim 1, wherein the location of the second time slot is a shortest time before the time slot of the time resource allocation indication.

5. The method of claim 1, wherein a location of the second time slot based on one of the first time slot or the time slot indicated by the time resource allocation is configured by a base station or predefined.

6. The method of claim 1, wherein the first UE is a destination of the shared channel transmitted from the second UE.

7. The method of claim 1, wherein the feedback channel is a physical side uplink feedback channel (PFSCH).

8. The method of claim 1, wherein the enabling of transmitting the collision indicator is configured by higher layer signaling.

9. The method of claim 1, wherein the SCI further comprises 1-bit information indicating that the second UE is capable of receiving the collision indicator from the first UE.

10. The method of claim 9, wherein the SCI includes fewer reserved bits when the second UE is to transmit the 1-bit information.

11. The method of claim 9 wherein the first UE monitors a set of frequency resources indicated by a time resource allocation in the SCI.

12. The method of claim 1, wherein the feedback channel comprises a first set of resources carrying an Acknowledgement (ACK) or a Negative ACK (NACK) for a received shared channel and a second set of resources comprising resources of the feedback channel carrying the collision indicator.

13. The method of claim 12, wherein the first set of resources and the second set of resources are located on different frequency resources.

14. The method of claim 1, wherein the transmitting a collision indicator comprises:

the first UE sends the collision indicator to the second UE according to the priority indicated in the SCI.

15. A method, comprising:

a second User Equipment (UE) transmitting side uplink control information (sidelink control information, SCI) to the first UE in a first time slot, wherein the SCI comprises a resource reservation of a shared channel, the resource reservation indicating a set of frequency resources and a time resource allocation;

The second UE receives a collision indicator from the first UE on a resource of a feedback channel,

wherein the resources of the feedback channel include a second time slot for receiving the collision indicator, the location of the second time slot being based on one of the following time slots: the first time slot or the time slot indicated by the time resource allocation,

16. The method of claim 15, wherein the collision indicator indicates a sensed-based potential resource collision on the time resource allocation or a detected resource collision on the time resource allocation or the collision indicator indicates a sensed-based potential resource collision on the set of frequency resources or a detected resource collision on the set of frequency resources.

17. The method of claim 15, wherein the second time slot is located immediately after the first time slot plus a time interval.

18. The method of claim 15, wherein the location of the second time slot is a shortest time before the time slot of the time resource allocation indication.

19. The method of claim 15, wherein a location of the second time slot based on one of the first time slot or the time slot indicated by the time resource allocation is configured by a base station or predefined.

20. The method of claim 15, wherein the first UE is a destination of the shared channel transmitted from the second UE.

21. The method of claim 15, wherein the feedback channel is a physical side uplink feedback channel (PFSCH).

22. The method of claim 15, wherein the enabling of receiving the collision indicator is configured by higher layer signaling.

23. The method of claim 15 wherein the SCI further comprises 1-bit information indicating that the second UE is capable of receiving the collision indicator from the first UE.

24. The method of claim 23, wherein the SCI comprises fewer reserved bits when the second UE is to transmit the 1-bit information.

25. The method of claim 15, wherein the feedback channel comprises a first set of resources carrying an Acknowledgement (ACK) or a Negative ACK (NACK) for a received shared channel and a second set of resources comprising resources of the feedback channel carrying the collision indicator.

26. The method of claim 25, wherein the first set of resources and the second set of resources are located on different frequency resources.

27. The method of claim 15, wherein the receiving a collision indicator comprises:

the second UE receives the collision indicator from the first UE according to the priority indicated in the SCI.

28. A first User Equipment (UE), comprising:

a non-transitory memory comprising instructions;

one or more processors in communication with the non-transitory memory, wherein the instructions, when executed by the one or more processors, cause the first UE to perform the method of any of claims 1-14.

29. A second User Equipment (UE), comprising:

a non-transitory memory comprising instructions;

one or more processors in communication with the non-transitory memory, wherein the instructions, when executed by the one or more processors, cause the second UE to perform the method of any of claims 15-28.