Relay selection and re-selection assisted by discovery information
View Patent ↗Certain aspects of the present disclosure provide techniques for relay selection and reselection based on discovery information. An example method generally includes receiving, from a network entity, relay selection assistance information identifying a plurality of relay UEs available for selection by the UE; selecting a first relay UE of the plurality of relay UEs based, at least in part, on the relay selection assistance information; and connecting, via a sidelink, to the selected first relay UE.
1 . An apparatus for wireless communications at a user equipment (UE), comprising:
one or more memories comprising instructions; and
one or more processors, individually or collectively, configured to execute the instructions to cause the apparatus to:
receive, from a network entity, relay selection assistance information identifying a plurality of relay UEs available for selection by the UE;
select a first relay UE of the plurality of relay UEs based, at least in part, on the relay selection assistance information, wherein selecting the first relay UE of the plurality of relay UEs comprises selecting the first relay UE from a subset of the plurality of relay UEs, each relay UE in the subset being associated with a same cell as the UE and having a signal strength exceeding a threshold signal strength; and
connect, via a sidelink, to the selected first relay UE.
2 . The apparatus of claim 1 , wherein the relay selection assistance information is received in a discovery message.
3 . The apparatus of claim 1 , wherein the relay selection assistance information is received in a dedicated message received during a discovery procedure.
4 . The apparatus of claim 1 , wherein the relay selection assistance information is received in a system information block (SIB) broadcast to the UE by the network entity.
5 . The apparatus of claim 1 , wherein the relay selection assistance information comprises information related to UE-to-network entity relays, and wherein the relay selection assistance information is organized on a per-cell basis.
6 . The apparatus of claim 5 , wherein the relay selection assistance information for each cell comprises one or more of:
cell identifier information,
cell load information,
minimum quality of service (QOS) metrics supported by a link between a relay UE and the cell;
neighbor relay information;
a connection status of each neighbor relay;
public land mobile network (PLMN) information for the cell; or
relay selection and reselection parameters for relay UEs connected with the cell.
7 . The apparatus of claim 1 , wherein the relay selection assistance information comprises information related to UE-to-UE relays that are in coverage of the network entity, and wherein the relay selection assistance information is organized on a per-UE basis.
8 . The apparatus of claim 7 , wherein the relay selection assistance information for each relay UE comprises one or more of:
information identifying the relay UE,
cell identifier information for cells associated with the relay UE,
cell load information for cells associated with the relay UE,
minimum quality of service (QOS) metrics supported by a link between the relay UE and the cell;
neighbor relay information;
a connection status of each neighbor relay;
public land mobile network (PLMN) information for the cell associated with the relay UE; or
relay selection and reselection parameters for the relay UE.
9 . The apparatus of claim 1 , wherein the one or more processors, individually or collectively, are configured to execute the instructions to cause the apparatus to:
adjust radio link monitoring (RLM) parameters for performing measurements in respect of the network entity where the UE is in a connected mode.
10 . The apparatus of claim 1 , wherein the one or more processors, individually or collectively, are configured to execute the instructions to cause the apparatus to:
establish a unicast connection with each relay UE in the subset of relay UEs.
11 . The apparatus of claim 10 , wherein the one or more processors, individually or collectively, are configured to execute the instructions to cause the apparatus to:
determine that a measured signal strength for a relay UE in the subset of relay UEs has fallen below the threshold signal strength;
based on at least the determination, send a sidelink medium access control (MAC) control element (CE) (MAC-CE) to activate the relay UE in the subset of relay UEs; and
terminate the unicast connection for the relay UE in the subset of relay UEs.
12 . The apparatus of claim 10 , wherein the one or more processors, individually or collectively, are configured to execute the instructions to cause the apparatus to:
measure a signal strength of a connection with the selected first relay UE; and
measure signal strength for only the subset of relay UEs based on a determination that the measured signal strength of the connection with the selected first relay UE exceeds the threshold signal strength.
13 . The apparatus of claim 10 , wherein the one or more processors, individually or collectively, are configured to execute the instructions to cause the apparatus to:
measure a signal strength of a connection with a relay UE having a lowest signal strength in the subset of relay UEs; and
measure signal strength for only the subset of relay UEs based on a determination that the measured signal strength of the connection with the relay UE having the lowest signal strength in the subset of relay UEs exceeds the threshold signal strength.
14 . The apparatus of claim 10 , wherein the one or more processors, individually or collectively, are configured to execute the instructions to cause the apparatus to:
measure a signal strength of at least one of a connection with the selected first relay UE or a connection with a relay UE having a lowest signal strength in the subset of relay UEs; and
measure signal strength for the plurality of relay UEs based on a determination that at least one of the measured signal strength of the connection with the selected first relay UE or the measured signal strength of the connection with the relay UE having a lowest signal strength in the subset of relay UEs is less than the threshold signal strength.
15 . The apparatus of claim 10 , wherein the one or more processors, individually or collectively, are configured to execute the instructions to cause the apparatus to:
determine that a signal strength of a connection with the selected first relay UE has fallen below a threshold signal strength; and
based on the determination:
release the connection with the selected first relay UE; and
activate a connection with a second relay UE of the subset of relay UEs via a sidelink medium access control (MAC) control element (CE) (MAC-CE), wherein second relay UE comprises a UE of the subset of relay UEs having a highest connection signal strength.
16 . The apparatus of claim 10 , wherein the one or more processors, individually or collectively, are configured to execute the instructions to cause the apparatus to:
determine that a signal strength of a connection with the selected first relay UE has fallen below a threshold signal strength and that no relay UE in the subset of relay UEs is suitable for reselection; and
based on the determination:
release the connection with the selected first relay UE; and
trigger a cell reselection procedure.
17 . The apparatus of claim 1 , wherein the one or more processors, individually or collectively, are configured to execute the instructions to cause the apparatus to adjust radio resource management (RRM) parameters for performing measurements in respect of the network entity and one or more neighboring network entities where the UE is in an idle, inactive, or connected mode using a first set of adjusted RRM parameters for the network entity and a second set of adjusted RRM parameters for the one or more neighboring network entities.
18 . A method for wireless communications at a user equipment (UE), comprising:
receiving, from a network entity, relay selection assistance information identifying a plurality of relay UEs available for selection by the UE;
selecting a first relay UE of the plurality of relay UEs based, at least in part, on the relay selection assistance information, wherein selecting the first relay UE of the plurality of relay UEs comprises selecting the first relay UE from a subset of the plurality of relay UEs, each relay UE in the subset being associated with a same cell as the UE and having a signal strength exceeding a threshold signal strength; and
connecting, via a sidelink, to the selected first relay UE.