Sidelink relay enhancements to support multipath

1 . An apparatus to be used in a user equipment (UE) configured for operation in a fifth-generation new-radio (5G NR) network, wherein the apparatus comprises:

a memory to store a medium access control (MAC) control element (CE) that is received from a gNodeB (gNB) of a serving cell to which the UE and a relay UE belong, the MAC CE to activate a sidelink radio bearer (SLRB) for packet data convergence protocol (PDCP) duplication; and

one or more processors to identify, based on the MAC CE, that the UE is to communicate with the gNB via multiple communication paths comprising:

a direct path comprising a first communication link directly between the UE and the gNB, the first communication link being over a uU interface of the 5G NR network; and

a relayed path comprising a sidelink between the UE and the relay UE using a sidelink interface, and a second communication link over the uU interface directly between the relay UE and the gNB,

wherein:

the sidelink interface uses the SLRB,

the uU interface and the sidelink interface use channels in different operating bands, and

the one or more processors are configured to perform the PDCP duplication per radio bearer using the direct and relayed paths.

2 . The apparatus of claim 1 , wherein prior to communicating via the multiple communication paths, the apparatus is to:

perform, based on the MAC CE, measurement of a link of the direct path or the relayed path; and

report, to the gNB prior to performance of the communicating via the multiple communication paths, a result of the measurement.

3 . The apparatus of claim 1 , wherein the MAC CE is a first MAC CE, and wherein the one or more processors are further to deactivate, based on a second MAC CE received from the gNB, the SLRB PDCP duplication.

4 . One or more non-transitory computer-readable media comprising instructions that, upon execution of the instructions by one or more processors, are to cause a gNodeB (gNB) for operation in a fifth-generation new-radio (5G NR) network to:

generate a medium access control (MAC) control element (CE) that includes an indication that a remote UE of a serving cell to which the gNB and a relay UE belong is to activate a sidelink radio bearer (SLRB) for packet data convergence protocol (PDCP) duplication using multiple communication paths; and

transmit the MAC CE to the remote UE;

wherein performing the PDCP duplication using the multiple communication paths comprises

a direct path comprising a first communication link directly between the UE and the gNB, the first communication link being over a uU interface of the 5G NR network; and

a relayed path comprising a sidelink between the UE and the relay UE using a sidelink interface, and a second communication link over the uU interface directly between the relay UE and the gNB,

wherein:

the sidelink interface uses the SLRB,

the uU interface and the sidelink interface use channels in different operating bands, and the one or more processors are configured to perform the PDCP duplication per radio bearer using the direct and relayed paths.

5 . The one or more non-transitory computer-readable media of claim 4 , wherein prior to communicating via the multiple communication paths, the gNB is configured to receive a measurement of a link of the direct path or the relayed path from the UE.

6 . The one or more non-transitory computer-readable media of claim 4 , wherein the instructions are further to transmit, from the gNB to the remote UE, a second MAC CE that includes an indication that the remote UE is to deactivate the SLRB PDCP duplication.

7 . The apparatus of claim 1 , wherein the sidelink interface is a PC5 interface.

8 . The one or more non-transitory computer-readable media of claim 4 wherein the sidelink interface is a PC5 interface.