Sounding reference signal based uplink to downlink channel occupancy time sharing
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive, from a base station, a grant including information for triggering a clear channel assessment based sounding reference signal (SRS) transmission. The UE may perform the clear channel assessment for a channel based at least in part on receiving the grant. The UE may transmit, to the base station, the SRS that initiates a shared channel occupancy time (COT) on the channel based at least in part on performing the clear channel assessment. Numerous other aspects are provided.
1 . A method of wireless communication performed by a user equipment (UE), comprising:
receiving, from a base station, a grant including information for triggering a clear channel assessment based sounding reference signal (SRS) transmission, wherein the information includes downlink grant downlink control information (DCI) with a frequency domain resource allocation (FDRA) field indicating an invalid FDRA assignment;
performing the clear channel assessment for a channel based at least in part on receiving the grant;
transmitting, to the base station, the SRS that initiates an uplink to downlink shared channel occupancy time (COT) on the channel based at least in part on performing the clear channel assessment; and
receiving, from the base station, downlink data transmitted on the channel in the shared COT.
2 . The method of claim 1 ,
wherein the clear channel assessment is an extended clear channel assessment.
3 . The method of claim 1 ,
wherein the clear channel assessment is a listen-before-talk (LBT) procedure.
4 . The method of claim 3 ,
wherein the LBT procedure is a Category 4 LBT procedure.
5 . The method of claim 1 ,
wherein the DCI including an indication for triggering transmission of the SRS and an indication of a type of the clear channel assessment.
6 . The method of claim 1 ,
wherein the DCI includes an indication for triggering transmission of the SRS and does not include a valid physical downlink shared data channel (PDSCH) assignment.
7 . The method of claim 6 ,
wherein transmitting the SRS that initiates the shared COT on the channel comprises:
transmitting the SRS without transmitting a physical uplink control channel (PUCCH) communication based at least in part on the downlink grant DCI that includes the indication for triggering transmission of the SRS and does not include a valid PDSCH assignment.
8 . The method of claim 1 , further comprising:
receiving, from the base station, another information for triggering another clear channel assessment based SRS transmission, wherein the other information includes an uplink grant DCI that includes an indication for triggering transmission of the SRS and does not include a valid physical uplink shared data channel (PUSCH) assignment.
9 . The method of claim 1 ,
wherein the channel is in an unlicensed spectrum.
10 . The method of claim 1 ,
wherein the grant includes an indication of a time offset between the UE receiving the grant and the UE transmitting the SRS.
11 . A method of wireless communication performed by a base station, comprising:
transmitting, to a user equipment (UE), a grant including information for triggering a clear channel assessment based sounding reference signal (SRS) transmission, wherein the information includes downlink grant downlink control information (DCI) with a frequency domain resource allocation (FDRA) field indicating an invalid FDRA assignment;
receiving, from the UE, the SRS that initiates an uplink to downlink shared channel occupancy time (COT) on a channel based at least in part on the grant; and
transmitting downlink data to the UE on the channel in the shared COT.
12 . The method of claim 11 ,
wherein the clear channel assessment is an extended clear channel assessment.
13 . The method of claim 11 ,
wherein the clear channel assessment is a listen-before-talk (LBT) procedure.
14 . The method of claim 13 ,
wherein the LBT procedure is a Category 4 LBT procedure.
15 . The method of claim 11 ,
wherein the DCI includes an indication for triggering transmission of the SRS and an indication of a type of the clear channel assessment.
16 . The method of claim 11 ,
wherein the DCI includes an indication for triggering transmission of the SRS and does not include a valid physical downlink shared data channel (PDSCH) assignment.
17 . The method of claim 11 , further comprising:
transmitting, to the UE, another information for triggering another clear channel assessment based SRS transmission, wherein the other information includes an uplink grant DCI that includes an indication for triggering transmission of the SRS and does not include a valid physical uplink shared data channel (PUSCH) assignment.
18 . The method of claim 11 ,
wherein the channel is in an unlicensed spectrum.
19 . The method of claim 18 ,
wherein the grant includes an indication of a time offset between the UE receiving the grant and the UE transmitting the SRS.
20 . A user equipment (UE) for wireless communication, comprising:
a memory; and
one or more processors operatively coupled to the memory, the memory and the one or more processors configured to:
receive, from a base station, a grant including information for triggering a clear channel assessment based sounding reference signal (SRS) transmission, wherein the information includes downlink grant downlink control information (DCI) with a frequency domain resource allocation (FDRA) field indicating an invalid FDRA assignment;
perform the clear channel assessment for a channel based at least in part on receiving the grant;
transmit, to the base station, the SRS that initiates shared channel occupancy time (COT) on the channel based at least in part on performing the clear channel assessment; and
receive, from the base station, downlink data transmitted on the channel in the shared COT.
21 . The UE of claim 20 ,
wherein the DCI including an indication for triggering transmission of the SRS and an indication of a type of the clear channel assessment.
22 . The UE of claim 20 ,
wherein the DCI includes an indication for triggering transmission of the SRS and does not include a valid physical downlink shared data channel (PDSCH) assignment.
23 . The UE of claim 22 ,
wherein the one or more processors are further configured to:
transmit the SRS without transmitting a physical uplink control channel (PUCCH) communication based at least in part on the downlink grant DCI that includes the indication for triggering transmission of the SRS and does not include a valid PDSCH assignment.
24 . The UE of claim 20 ,
wherein the one or more processors are further configured to:
receive, from the base station, another information for triggering another clear channel assessment based SRS transmission, wherein the other information includes an uplink grant DCI that includes an indication for triggering transmission of the SRS and does not include a valid physical uplink shared data channel (PUSCH) assignment.
25 . The UE of claim 20 ,
wherein the clear channel assessment is a listen-before-talk (LBT) procedure.
26 . The UE of claim 20 ,
wherein the grant includes an indication of a time offset between the UE receiving the grant and the UE transmitting the SRS.
27 . A base station for wireless communication, comprising:
a memory; and
one or more processors operatively coupled to the memory, the memory and the one or more processors configured to:
transmit, to a user equipment (UE), a grant including information for triggering a clear channel assessment based sounding reference signal (SRS) transmission, wherein the information includes downlink grant downlink control information (DCI) with a frequency domain resource allocation (FDRA) field indicating an invalid FDRA assignment;
receive, from the UE, the SRS that initiates an uplink to downlink shared channel occupancy time (COT) on a channel based at least in part on the grant; and
transmit downlink data to the UE on the channel in the shared COT.
28 . The base station of claim 27 ,
wherein the DCI includes an indication for triggering transmission of the SRS and an indication of a type of the clear channel assessment.
29 . The base station of claim 27 ,
wherein the DCI includes an indication for triggering transmission of the SRS and does not include a valid physical downlink shared data channel (PDSCH) assignment.
30 . The base station of claim 27 ,
wherein the one or more processors are further configured to:
transmit, to the UE, another information for triggering another clear channel assessment based SRS transmission, wherein the other information includes an uplink grant DCI that includes an indication for triggering transmission of the SRS and does not include a valid physical uplink shared data channel (PUSCH) assignment.