Techniques for selecting and reselecting sidelink relay

A method for wireless communications at a second user equipment (UE), comprising:

• monitoring for a relay discovery announcement on a sidelink channel to establish relay communications with a first UE operating as a relay UE, wherein the relay communications are associated with a quality of service level;
• receiving the relay discovery announcement via a broadcast on the sidelink channel from the first UE, wherein the first UE supports the quality of service level for the relay communications;
• and
• establishing the relay communications with the first UE based at least in part on receiving the relay discovery announcement.

A method for wireless communications at a base station, comprising:

• receiving a relay discovery request message comprising a quality of service level for relay communications between a first user equipment (UE) and a second UE;
• transmitting a relay discovery response message comprising an application code for relay discovery based at least in part on the quality of service level for the relay communications;
• configuring the first UE with a set of resources on a sidelink channel for a relay discovery announcement on the sidelink channel;
• and
• receiving, from the first UE, data for the second UE based at least in part on the relay communications between the first UE and the second UE.

An apparatus for wireless communications at a first user equipment (UE), comprising:

• a processor,
• memory coupled with the processor;
• and
• instructions stored in the memory and executable by the processor to cause the apparatus to:
• determine to operate as a relay UE based at least in part on a set of thresholds configured for the first UE;
• transmit a relay discovery announcement on a sidelink channel indicating support for relay communications based at least in part on the determination to operate as the relay UE;
• and
• establish the relay communications with a second UE based at least in part on the transmission of the relay discovery announcement on the sidelink channel.