Relay adaptation protocol layer configuration

1. An apparatus for wireless communication at a relay user equipment (UE), comprising:

a memory; and

one or more processors, coupled to the memory, configured to:

establish a connection with a remote UE for relaying communication;

receive, from a network entity, configuration information comprising:

remote UE connection identifier information associated with the connection between the remote UE and the relay UE for a relay service, and

a configuration including relaying channel identifier information, wherein the configuration is for the connection between the remote UE and the relay UE and for a link with the network entity, wherein the configuration indicates a relaying channel mapping, wherein the relaying channel mapping is between one or more relaying channels of the connection to one or more relaying channels of the link with the network entity, wherein the configuration is based at least in part on a relay adaptation protocol (RAP) layer supporting a radio bearer mapping between one or more radio bearers associated with the remote UE and the one or more relaying channels;

configure the one or more relaying channels of the connection and the one or more relaying channels of the link with the network entity based at least in part on the configuration information; and

relay communications between the remote UE and the network entity based at least in part on the configuration information.

2. The apparatus of claim 1 , wherein at least part of the configuration information is used by the RAP layer to relay the communications.

3. The apparatus of claim 1 , wherein the relaying channel mapping uses one of:

a one-to-one basis, or

an N-to-one basis, where N is variable.

4. The apparatus of claim 1 , wherein the connection is at least one of:

a sidelink unicast link setup using a sidelink signaling interface,

a Bluetooth connection,

a WiFi connection, or

a device to device connection.

5. The apparatus of claim 1 , wherein the remote UE connection identifier information corresponds to a remote UE index, wherein the connection is uniquely associated with an assigned remote UE connection identifier identified by the remote UE connection identifier information.

6. The apparatus of claim 1 , wherein the one or more processors are further configured to:

assign a unique index associated with the connection, wherein the unique index is an assigned remote UE connection identifier identified by the remote UE connection identifier information; and

transmit information indicating the unique index to the network entity via a radio resource control message.

7. The apparatus of claim 6 , wherein the one or more radio bearers comprise a set of one or more sidelink dedicated radio bearers or signaling radio bearers, wherein the set of one or more sidelink dedicated radio bearers or signaling radio bearers use a same security setting based at least in part on the connection associated with the relay service.

8. The apparatus of claim 1 , wherein the communications are relayed via multiple radio access relaying channels mapped to multiple relaying channels associated with multiple remote UEs.

9. The apparatus of claim 1 , wherein relaying the communications is based at least in part on a RAP header, wherein the RAP header indicates one or more of:

an identifier of the remote UE based at least in part on a unique identifier of the connection,

the one or more relaying channels of the connection associated with the one or more radio bearers associated with the remote UE, or

a path identifier for data routing associated with the relay service.

10. The apparatus of claim 1 , wherein the one or more radio bearers comprise a radio access data radio bearer of the remote UE, wherein relaying the communications is based at least in part on the radio access data radio bearer of a remote UE protocol data unit session configured to satisfy a quality of service associated with the relay service.

11. The apparatus of claim 1 , wherein the one or more radio bearers comprise one or more radio access signaling radio bearers or one or more radio access data radio bearers of the remote UE, wherein the one or more relaying channels of the connection correspond to the one or more radio access signaling radio bearers or one or more radio access data radio bearers of the remote UE.

12. The apparatus of claim 1 , wherein the one or more radio bearers comprise a plurality of remote UE radio access signaling radio bearers, wherein the configuration information indicates the plurality of remote UE radio access signaling radio bearers that are multiplexed onto a single relaying channel for the connection based at least in part on one or more indexes of the plurality of remote UE radio access signaling radio bearers.

13. The apparatus of claim 1 , wherein the one or more radio bearers comprise multiple radio access signaling radio bearers associated with the remote UE, wherein the configuration information indicates a radio access relaying channel that is configured for multiplexing the multiple radio access signaling radio bearers associated with the remote UE.

14. The apparatus of claim 1 , wherein the relaying is performed by the RAP layer based at least in part on a backhaul adaptation protocol (BAP) associated with an integrated access backhaul technology.

15. The apparatus of claim 14 , wherein the one or more processors are further configured to:

exchange, with the remote UE, one or more relaying channel identifiers for the connection while configuring the connection for the relay service.

16. The apparatus of claim 15 , wherein the one or more processors are further configured to:

receive, from the remote UE, information indicating a remote UE connection identifier;

associate the remote UE connection identifier to the connection between the remote UE and the relay UE; and

transmit the remote UE connection identifier to the network entity via a radio resource control message.

17. The apparatus of claim 1 , wherein the one or more processors are further configured to:

configure a privacy setting for the relay service;

determine to update identifiers of the connection;

perform a connection identifier update with the remote UE;

update one or more radio access relaying channel identifiers and an assigned remote UE index based at least in part on a successful result of the connection identifier update; and

transmit a message to the network entity indicating a successful result of the connection identifier update, wherein the connection identifier update indication includes an updated remote UE index assigned for the connection based at least in part on the connection identifier update.

18. The apparatus of claim 1 , wherein the one or more processors are further configured to:

release the connection; and

transmit, to the network entity, an indication that the connection has been released.

19. An apparatus for wireless communication at a network entity, comprising:

a memory; and

one or more processors, coupled to the memory, configured to:

transmit, to a relay user equipment (UE), configuration information comprising:

remote UE connection identifier information associated with a connection between a remote UE and the relay UE for a relay service, and

a configuration including relaying channel identifier information, wherein the configuration is for the connection between the remote UE and the relay UE and for a link with the network entity, wherein the configuration indicates a relaying channel mapping, wherein the relaying channel mapping is between one or more relaying channels of the connection to one or more relaying channels of the link with the network entity, wherein the configuration is based at least in part on a relay adaptation protocol (RAP) layer supporting a radio bearer mapping between a radio bearer associated with the remote UE and the one or more relaying channels; and

communicate with the remote UE via the relay UE based at least in part on the configuration information.

20. The apparatus of claim 19 , wherein the one or more radio bearers comprise one or more radio access signaling radio bearers or one or more radio access data radio bearers of the remote UE, and wherein the configuration information indicates the one or more relaying channels of the connection correspond to the one or more radio access signaling radio bearers or the one or more radio access data radio bearers of the remote UE.

21. The apparatus of claim 19 , wherein the remote UE is associated with a radio access inactive state, a radio access idle state, or an out-of-coverage state, wherein the one or more radio bearers comprise one or more remote UE signaling or data radio bearers, and wherein the one or more processors, to transmit the configuration information, are configured to:

transmit the configuration information based at least in part on receiving an indication by the relay UE regarding setup of the connection with the remote UE for relaying; or

transmit the configuration information based at least in part on successful configuration of the connection with the remote UE, and

wherein the one or more processors are further configured to:

transmit, to the remote UE, information indicating a remote UE index, the one or more remote UE signaling or data radio bearers, and one or more relaying channel identifiers associated with the one or more relaying channels of the connection.

22. The apparatus of claim 19 , wherein the one or more radio bearers comprise one or more remote UE data radio bearers or signaling radio bearers, wherein the remote UE is in a radio access connected mode, and wherein the one or more processors, to transmit the configuration information, are further configured to:

transmit the configuration information based at least in part on a handover of the remote UE from a radio access connection to a relaying connection via the connection, wherein the configuration information includes a bearer configuration associated with the one or more remote UE data radio bearers or signaling radio bearers.

23. The apparatus of claim 22 , wherein the one or more processors are further configured to:

transmit, to the remote UE in a handover command, information indicating a remote UE index associated with the remote UE.

24. The apparatus of claim 22 , wherein the one or more processors are further configured to:

receive, from the relay UE, a connection index determined by the relay UE via a radio resource control message.

25. The apparatus of claim 19 , wherein the one or more processors are further configured to:

receive a notification from the relay UE indicating that a connection identifier update procedure is successful, wherein the notification includes a new remote UE index assigned for the connection.

26. The apparatus of claim 19 , wherein the one or more processors are further configured to:

transmit a release indication that indicates to release the connection, wherein the release indication is based at least in part on at least one of:

a handover of the remote UE to a radio access connection,

a load associated with the relay UE, or

a quality of service requirement.

27. The apparatus of claim 19 , wherein the one or more processors are further configured to:

receive a RAP protocol data unit (PDU);

determine a signaling radio bearer or data radio bearer of the one or more radio bearers associated with the remote UE based at least in part on a RAP header of the received RAP PDU;

remove the RAP header; and

transfer a New Radio packet data convergence protocol (PDCP) PDU of the RAP PDU to an upper layer.

28. The apparatus of claim 19 , wherein the one or more processors are further configured to:

determine a remote UE index associated with the connection of the remote UE;

determine a relaying channel for the connection of the remote UE corresponding to a radio access bearer of the remote UE,

determine a radio access relaying channel corresponding to the relaying channel for the connection of the remote UE;

generate a RAP header including at least one of the remote UE Index, a relaying channel identifier of the relaying channel for the connection of the remote UE, or a path identifier; and

transmit a RAP layer protocol data unit (PDU) with the RAP header on the radio access relaying channel.

29. An apparatus for wireless communication at a remote user equipment (UE), comprising:

a memory; and

one or more processors, coupled to the memory, configured to:

establish a connection with a relay UE;

configure one or more relaying channels for the connection based at least in part on configuration information, wherein the configuration information comprises:

remote UE connection identifier information associated with the connection between the remote UE and the relay UE for a relay service, and

a configuration for one or more relaying channels for the connection between the remote UE and the relay UE, wherein the configuration indicates a relaying channel mapping, wherein the relaying channel mapping is between one or more relaying channels of the connection to one or more relaying channels of a link between the relay UE and a network entity, wherein the configuration is based at least in part on a relay adaptation protocol (RAP) layer supporting a radio bearer mapping between one or more radio bearers associated with the remote UE and the one or more relaying channels; and

communicate with the network entity via the relay UE based at least in part on the configuration information.

30. The apparatus of claim 29 , wherein the relay service is identified by a relay service code, and wherein establishment of the connection is based at least in part on a security setting corresponding to the relay service code.

31. The apparatus of claim 29 , wherein the one or more radio bearers comprise multiple radio access signaling radio bearers, wherein a relaying channel, of the one or more relaying channels, is associated with the multiple radio access signaling radio bearers, and wherein a relay adaption protocol layer of the remote UE indicates an index of a selected radio access signaling radio bearer of the multiple radio access signaling radio bearers for a communication via the relaying channel.

32. The apparatus of claim 29 , wherein the one or more radio bearers comprise a radio access signaling or data radio bearer, wherein the remote UE is associated with a radio access inactive state, a radio access idle state, or an out-of-coverage state, and wherein the one or more processors are further configured to:

receive, in connection with configuring the radio access signaling or data radio bearer, information indicating a remote UE index of the remote UE, a configuration of the radio access signaling or data radio bearer, and a relaying channel configuration including a relaying channel identifier for a relaying channel of the one or more relaying channels of the connection.

33. The apparatus of claim 32 , wherein the one or more processors are further configured to:

transmit, to the relay UE, information indicating a connection index for the connection.

34. The apparatus of claim 29 , wherein the one or more processors are further configured to:

receive, in connection with a connection identifier update procedure, information indicating an updated remote UE index of the remote UE.

35. The apparatus of claim 29 , wherein the one or more processors are further configured to:

transmit, to the relay UE, a link identifier update request based at least in part on a timer; and

perform a connection identifier update procedure with the relay UE based at least in part on the link identifier update request.