Beam switching after performing listen-before-talk
Apparatuses, methods, and systems are disclosed for receiver-assisted interference mitigation. One apparatus includes a processor and a transceiver that is operable on unlicensed spectrum, where the transceiver includes a plurality of UE panels. The processor generates a first TB for a first UL channel resource. Here, the first TB contains control signaling or data. The processor performs a directional LBT procedure for a first panel associated with the first UL channel resource and transmits request information to a RAN node using the first UL channel resource in response to successful directional LBT. The processor receives feedback information from the RAN node in response to the request information and transmits the first TB using the first UL channel resource in response to receiving the feedback information.
1. A method performed by a user equipment (“UE”), the method comprising:
generating a first transport block (“TB”) for a first uplink (“UL”) channel resource;
performing a directional listen-before-talk (“LBT”) procedure for a first beam associated with the first UL channel resource;
transmitting, to a radio access network (“RAN”) node, request information using the first UL channel resource in response to successful directional LBT, wherein the request information comprises a previously configured sounding reference signal (“SRS”) sequence;
receiving, from the RAN node, feedback information in response to the request information; and
transmitting the first TB using the first UL channel resource in response to receiving the feedback information.
2. The method of claim 1 , further comprising receiving a first message that configures a plurality of UL channel resources, wherein each UL channel resource is associated with a beam at the UE.
3. The method of claim 2 , wherein the first message is a UE-specific radio resource control (“RRC”) message.
4. The method of claim 2 , wherein the UL channel resources include at least one physical uplink control channel (“PUCCH”) resource and/or at least one physical uplink shared channel (“PUSCH”) resource, where a spatial relation for the PUCCH resource is indicated by medium access control (“MAC”) Control Element (“CE”) and a spatial relation for the PUSCH resource is based on one of: the spatial relation for the PUCCH resource, or a downlink reference signal.
5. The method of claim 1 , further comprising;
initiating a timer in response to transmitting the request information, wherein the timer defines a period for monitoring for the feedback information; and
stopping transmission of the first TB if no feedback information is received before expiry of the timer.
6. The method of claim 5 , wherein the request information comprises first request information, the method further comprising:
switching to a second beam in response determining that no feedback information was received before expiry of the timer;
performing a second directional LBT procedure for the second beam; and
transmitting second request information using the second beam in response to successful direction LBT for the second beam.
7. The method of claim 6 , wherein transmitting the second request information comprises using a same configured grant (“CG”) resource as used to transmit the first request information.
8. The method of claim 6 , wherein transmitting the second request information comprises using a different configured grant (“CG”) resource than used to transmit the first request information.
9. The method of claim 1 , wherein performing the directional LBT procedure for the first beam comprises performing multiple directional LBT procedures simultaneously for a plurality of beams and selecting a set of beams after LBT success, the set of beams comprising the first beam, wherein transmitting the request information comprises transmitting request information simultaneously on the set of beams.
10. The method of claim 1 , wherein the request information comprises a single bit.
11. The method of claim 1 , wherein the request information comprises one or more of: a beam identifier (“ID”), a configured grant (“CG”) resource configuration, a channel access priority class, or a LBT type.
12. The method of claim 1 , wherein the request information comprises a demodulation reference signal (“DM-RS”).
13. The method of claim 1 , wherein the request information is scrambled using a beam identifier corresponding to the first beam.
14. The method of claim 1 , further comprising transmitting muting information in sidelink to one or more neighboring UEs.
15. A user equipment (“UE”) for wireless communication, comprising:
a transceiver operable on unlicensed spectrum, wherein the transceiver comprises a plurality of UE panels;
at least one memory; and
at least one processor coupled with the at least one memory and configured to cause the UE to:
generate a first transport block (“TB”) for a first uplink (“UL”) channel resource;
perform a directional listen-before-talk (“LBT”) procedure for a first panel associated with the first UL channel resource;
transmit, to a radio access network (“RAN”) node, request information using the first UL channel resource in response to successful directional LBT, wherein the request information comprises a previously configured sounding reference signal (“SRS”) sequence;
receive, from the RAN node, feedback information in response to the request information; and
transmit the first TB using the first UL channel resource in response to receiving the feedback information.
16. The UE of claim 15 , wherein the request information comprises a single bit.
17. The UE of claim 15 , wherein the request information comprises one or more of: a beam identifier (“ID”), a configured grant (“CG”) resource configuration, a channel access priority class, or a LBT type.
18. The UE of claim 15 , wherein the request information comprises a demodulation reference signal (“DM-RS”) or a reference sequence previously configured by the RAN node.
19. The UE of claim 15 , wherein the processor is configured to cause the UE to transmit muting information in sidelink to one or more neighboring UEs.