16.9.9.4 COT Sharing

UE to UE COT sharing is supported in NR sidelink operation for SL-U. When performing SL-SSB transmission(s), a responding UE can utilize a COT shared by a COT initiating UE when the responding UE intends to transmit SL-SSB in the shared COT. When performing PSFCH transmissions, a responding UE can utilize a COT shared by a COT initiating UE when at least one of the responding UE's PSFCH transmissions is intended for the COT initiating UE.

When performing PSSCH/PSCCH transmissions, a responding UE can utilize a COT shared by a COT initiating UE when the responding UE's transmission(s) is intended for the COT initiating UE. In unicast, the destination/source ID of the responding UE's transmission should match the source/destination ID of the initiator UE's transmission for the same unicast link. In groupcast/broadcast, destination ID of the responding UE's transmission should match the initiator's destination ID. In addition, a COT initiating UE may transmit an additional pair of source/destination ID in either unicast, groupcast, or broadcast. In this case, the responding UE can utilize a COT shared by a COT initiating UE if the destination/source (for unicast) or destination (for groupcast/broadcast) of the responding UE transmission match what is carried in the additional ID(s). In all cases, a UE's transmissions in a shared COT should have SL-CAPC value that is equal to or smaller than the SL-CAPC value indicated in the COT sharing information. In order to satisfy the COT sharing requirements, a responding UE may perform an enhanced LCP procedure as specified in 38.321 [6]. When receiving multiple COT sharing indications from different COT initiators, it is up to UE implementation which shared COT is used.