Method and apparatus for radio sidelink operation over shared spectrum

Patent metadata

Field	Value
Publication number	US-2025038807-A1
Application number	US-202218710790-A
Country	US
Kind code	A1
Filing date	Nov 16, 2022
Priority date	Nov 16, 2021
Publication date	Jan 30, 2025
Grant date	—

Abstract

Methods and apparatuses are described herein to address issues at the MAC layer resulting from potential Listen-Before-Talk (LBT) failures and delayed transmission. For example, a wireless transmit/receive unit (WTRU) may monitor a plurality of TX resource pools within a sidelink bandwidth part (BWP) for LBT events. The WTRU may cause, based on determining that an LBT failure has occurred, a corrective action associated with a sidelink MAC procedure. The WTRU may determine, based on the LBT failure, that a total number or consecutive number of detected LBT failures for one of the monitored TX resource pools exceeds a threshold, indicating a consistent LBT failure. The WTRU may, based on the consistent LBT failure, send an indication of the consistent LBT failure for the TX resource pool to peer WTRUs. and an indication of the consistent LBT failure for the TX resource pool to a serving cell.

First claim

1 - 20 . (canceled)

21 . A wireless transmit/receive unit (WTRU), comprising:
a processor configured to: receive a request for channel state information (CSI) associated with a sidelink (SL) bandwidth; start an SL CSI time period based on receiving the request for the CSI; during the SL CSI time period,
perform a listen before talk (LBT) associated with a set of resources of the SL bandwidth, and
determine an LBT success associated with the set of resources; and
end the SL CSI time period based on the LBT success.

22 . The WTRU of claim 21 , wherein the processor is further configured to send the CSI on the set of resources of the SL bandwidth before the end of the SL CSI time period.

23 . The WTRU of claim 22 , wherein the set of resources is a first set of resources, and the processor is further configured to:
perform an LBT on a second set of resources associated with the SL bandwidth to determine a number of LBT failures associated with the second set of resources; determine, based on the number of LBT failures being equal to or greater than a CSLF threshold, that the second set of resources is associated with a consistent SL LBT failure (CSLF); and send an indication of the CSLF associated with the second set of resources.

24 . The WTRU of claim 23 , wherein the processor is further to:
receive an uplink (UL) grant; and generate an SL LBT failure medium access control (MAC) control element (CE), wherein the SL LBT failure MAC CE indicates the CSLF associated with the second set of resources, wherein the SL LBT failure MAC CE is sent according to the UL grant.

25 . The WTRU of claim 21 , wherein the processor is further configured to:
receive SL control information (SCI), wherein the SCI indicates the request for the CSI and triggers an SL CSI reporting procedure; and cancel the SL CSI reporting procedure based on the LBT success.

26 . The WTRU of claim 21 , wherein the WTRU is a first WTRU, and the request is received from a second WTRU, and wherein the first WTRU and the second WTRU are connected via a PC5 connection.

27 . The WTRU of claim 21 , wherein the processor is further configured to:
determine that an SL logical channel (LCH) comprising SL data is to be transmitted; determine that an SL BSR is to be sent on a first uplink (UL) resource to indicate a buffer status of the SL LCH; determine an LBT failure associated with the first UL resource; and send a scheduling request (SR) for a grant of a second UL resource to send the SL BSR.

28 . The WTRU of claim 21 , wherein the processor is further configured to:
receive configuration information indicating a threshold number of SL transmissions associated with a hybrid automatic repeat request (HARQ) procedure; determine a number of SL transmissions associated with the HARQ procedure, wherein the number of SL transmissions includes a first SL transmission and excludes a second SL transmission, and wherein the first SL transmission is sent on a resource associated with an LBT success, and the second SL transmission is sent on a resource associated with an LBT failure; and based on the number of SL transmissions associated with the HARQ procedure being equal to or greater than the threshold number of SL transmissions indicated in the configuration information, reset a HARQ buffer associated with the HARQ procedure.

29 . A method performed by a wireless transmit/receive unit (WTRU), comprising:
receiving a request for channel state information (CSI) associated with a sidelink (SL) bandwidth; starting an SL CSI time period based on receiving the request for the CSI; during the SL CSI time period,
performing a listen before talk (LBT) associated with a set of resources of the SL bandwidth, and
determining an LBT success associated with the set of resources; and
ending the SL CSI time period based on the LBT success.

30 . The method of claim 29 , wherein the method comprises sending the CSI on the set of resources of the SL bandwidth before the end of the SL CSI time period.

31 . The method of claim 30 , wherein the set of resources is a first set of resources, and the method further comprises:
performing an LBT on a second set of resources associated with the SL bandwidth to determine a number of LBT failures associated with the second set of resources; determining, based on the number of LBT failures being equal to or greater than a CSLF threshold, that the second set of resources is associated with a consistent SL LBT failure (CSLF); and sending an indication of the CSLF associated with the second set of resources.

32 . The method of claim 31 , wherein the method further comprises:
receiving an uplink (UL) grant; and generating an SL LBT failure medium access control (MAC) control element (CE), wherein the SL LBT failure MAC CE indicates the CSLF associated with the second set of resources, wherein the SL LBT failure MAC CE is sent according to the UL grant.

33 . The method of claim 29 , further comprising:
receiving SL control information (SCI), wherein the SCI indicates the request for the CSI and triggers an SL CSI reporting procedure; and cancelling the SL CSI reporting procedure based on the LBT success.

34 . The method of claim 29 , wherein the WTRU is a first WTRU, and the request is received from a second WTRU, and wherein the first WTRU and the second WTRU are connected via a PC5 connection.

35 . The method of claim 29 , further comprising:
determining that an SL logical channel (LCH) comprising SL data is to be transmitted; determining that an SL BSR is to be sent on a first uplink (UL) resource to indicate a buffer status of the SL LCH; determining an LBT failure associated with the first UL resource; and sending a scheduling request (SR) for a grant of a second UL resource to send the SL BSR.

36 . The method of claim 29 , further comprising:
receiving configuration information indicating a threshold number of SL transmissions associated with a hybrid automatic repeat request (HARQ) procedure; determining a number of SL transmissions associated with the HARQ procedure, wherein the number of SL transmissions includes a first SL transmission and excludes a second SL transmission, and wherein the first SL transmission is sent on a resource associated with an LBT success, and the second SL transmission is sent on a resource associated with an LBT failure; and based on the number of SL transmissions associated with the HARQ procedure being equal to or greater than the threshold number of SL transmissions indicated in the configuration information, resetting a HARQ buffer associated with the HARQ procedure.

Assignees

• Interdigital Patent Holdings Inc

Inventors

• Di Girolamo Rocco
• Adjakple Pascal
• Pan Kyle
• Tsai Allan
• Li Yifan

Classifications

• H04W74/0833

  Random access procedures, e.g. with 4-step access · CPC title

• H04L1/1896

  ARQ related signaling · CPC title

• H04W72/25

  between terminals via a wireless link, e.g. sidelink · CPC title

• H04B7/0626 Primary

  Channel coefficients, e.g. channel state information [CSI] · CPC title

• H04W76/14

  Direct-mode setup · CPC title