16.9.2.6 RRC

The RRC sublayer provides the following services and functions over the PC5 interface:

• Transfer of a PC5-RRC message between peer UEs;
• Maintenance and release of a PC5-RRC connection between two UEs;
• Detection of sidelink radio link failure for a PC5-RRC connection;
• Measurement configuration and reporting related to sidelink.

A PC5-RRC connection is a logical connection between two UEs for a pair of Source and Destination Layer-2 IDs which is considered to be established after a corresponding PC5 unicast link is established as specified in TS 23.287 [40]. There is one-to-one correspondence between the PC5-RRC connection and the PC5 unicast link. A UE may have multiple PC5-RRC connections with one or more UEs for different pairs of Source and Destination Layer-2 IDs.

Separate PC5-RRC procedures and messages are used for a UE to transfer UE capability and sidelink configuration to the peer UE, as specified in TS 38.331 [12]. Both peer UEs can exchange their own UE capability and sidelink configuration using separate bi-directional procedures in both sidelink directions.

If it is not interested in sidelink transmission, if sidelink RLF on the PC5-RRC connection is declared, or if the Layer-2 link release procedure is completed as specified in TS 23.287 [40], UE releases the PC5-RRC connection.