Interworking function selection by remote UE
Certain aspects of the present disclosure provide techniques for interworking function selection by a remote user equipment (UE) for UE-to-network sidelink relay access. A method that may be performed by a remote user equipment (UE) includes receiving a plurality of interworking function configurations, for accessing a network via a sidelink relay UE, and a plurality of relay service codes. The remote UE determines a service to use for communications in the network. The remote UE selects one of the plurality of interworking function configurations based on the relay service code for the determined service.
1 . A method for wireless communication by a remote user equipment (UE), the method comprising:
receiving sidelink policy information including a plurality of relay service codes (RSCs) and interworking function (IWF) selection information, the IWF selection information including an indication to select an IWF based on a tracking area identifier (TAI) or an operator identifier;
receiving an indication, from a sidelink relay UE, of the TAI corresponding to a location of the sidelink relay UE;
receiving an indication of a public land mobile network (PLMN) associated with the sidelink relay UE; and
selecting an IWF, for accessing a network via the sidelink relay UE, based on at least one of the plurality of RSCs for at least one service and on the IWF selection information.
2 . The method of claim 1 , wherein the IWF is associated with the least one of the plurality of RSCs.
3 . The method of claim 1 , wherein the IWF selection information includes a prioritized list of preferred PLMNs for IWF selection.
4 . The method of claim 3 , wherein the IWF selection information further includes home PLMNs (HPLMNs) associated with the PLMNs in the prioritized list of preferred PLMNs.
5 . The method of claim 4 , wherein the IWF selection information comprises fully qualified domain names (FQDNs) or Internet Protocol (IP) addresses of one or more IWFs in the HPLMN.
6 . The method of claim 4 , further comprising deriving fully qualified domain names (FQDNs) or Internet Protocol (IP) addresses of the IWF.
7 . The method of claim 4 , wherein:
the selected IWF is associated with an IWF in the HPLMN; and
the method further comprises determining an Internet protocol (IP) address of the IWF in the HPLMN using an identifier configuration of the selected IWF.
8 . The method of claim 1 , further comprising determining a fully qualified domain names (FQDN) for the selected IWF using the TAI of a tracking area in which the remote UE is located or the operator identifier of the PLMN associated with the selected IWF.
9 . The method of claim 1 , wherein the indication from the sidelink relay UE is received in a relay discovery additional information message.
10 . The method of claim 4 , wherein the selecting includes:
selecting the IWF associated with the HPLMN when the remote UE and the sidelink relay UE are located in the same HPLMN; and
selecting the IWF based on the prioritized list of preferred PLMNs when the remote UE and the sidelink relay UE are located in different HPLMNs.
11 . The method of claim 4 , wherein the selecting includes:
performing a sidelink relay discovery procedure;
determining to establish a sidelink unicast link only with relay UEs that are in a PLMN in the prioritized list of preferred PLMNs; and
selecting the IWF associated with one of the sidelink relay UEs.
12 . The method of claim 1 , wherein:
the network is a 3GPP network; and
the selected IWF is a non-3GPP IWF.
13 . The method of claim 1 , further comprising accessing the network via an access link or via a sidelink UE-to-network relay access provided by the sidelink relay UE.
14 . A method for wireless communication by a sidelink relay user equipment (UE), the method comprising:
receiving a plurality of relay service codes (RSCs);
providing an indication to a remote UE of a tracking area identifier (TAI) corresponding to a location of the sidelink relay UE;
receiving, from the remote UE via a sidelink, data and an identifier of an interworking function (IWF); and
forwarding the data to a network via the IWF based on the identifier.
15 . The method of claim 14 , wherein the indication is provided in a relay discovery additional information message.
16 . The method of claim 14 , wherein:
the network is a 3GPP network; and
the IWF comprises a non-3GPP IWF.
17 . The method of claim 14 , wherein the IWF is associated with a fully qualified domain name (FQDN) or Internet Protocol (IP) address.
18 . An apparatus for wireless communication, the apparatus comprising:
a receiver configured to receive sidelink policy information including a plurality of relay service codes (RSCs), interworking function (IWF) selection information, the IWF selection information including an indication to select an IWF based on a tracking area identifier (TAI) or an operator identifier;
a memory comprising computer executable code executable; and
at least one processor configured to execute the computer executable code to cause the apparatus to:
receive an indication from a sidelink relay UE, of the TAI corresponding to a location of the sidelink relay UE;
receive an indication of a public land mobile network (PLMN) associated with the sidelink relay UE; and
select an IWF, for accessing a network via the sidelink relay UE, from based on at least one of the plurality of RSCs for at least one service and on the IWF selection information.