Steering of roaming PLMN list update and management

1. An apparatus, comprising:

a memory; and

a processor in communication with the memory, wherein the processor is configured to:

receive, from a network, a steering of roaming (SoR) container, wherein the SoR container includes a list of operator preferred public land mobile network (OPLMNs);

store a prior list of OPLMNs stored on a universal subscriber identity module (USIM) on the memory;

replace the prior list of OPLMNs stored on the USIM with the list of OPLMNs included in the SoR container; and

treat, in response to losing a signal to a cell on a visited PLMN (VPLMN), PLMNs in an SoR aborted list as a lower priority than PLMNs stored on the USIM.

2. The apparatus of claim 1 ,

wherein the prior list of OPLMNs stored on the memory is treated as a lower priority list as compared to the list of OPLMNs stored on the USIM.

3. The apparatus of claim 1 ,

wherein the processor is further configured to:

in response to determining to move from a current public land mobile network (PLMN), scan for a new PLMN based on the list of OPLMNs stored on the USIM; and

in response to not discovering a PLMN corresponding to an OPLMN in the OPLMNs stored on the USIM, scan for a new PLMN based on the list of OPLMNs stored in the memory.

4. The apparatus of claim 1 ,

wherein the SoR container is a secured packet.

5. The apparatus of claim 1 ,

wherein the OPLMNs within the list are associated with a plurality of mobile country codes (MCCs).

6. The apparatus of claim 5 ,

wherein the processor is further configured to:

compare the list of OPLMNs included in the SoR container to the prior list of OPLMNs; and

replace OPLMNs in the prior list of OPLMNs that have an MCC corresponding to an MCC of the plurality of MCCs included in the list of OPLMNs.

7. The apparatus of claim 6 ,

wherein the processor is further configured to:

keep OPLMNs in the prior list of OPLMNs that do not have an MCC corresponding to an MCC of the plurality of MCCs included in the list of OPLMNs.

8. The apparatus of claim 5 ,

wherein the processor is further configured to:

compare the list of OPLMNs included in the SoR container to the prior list of OPLMNs; and

determine that at least a portion of OPLMNs in the prior list of OPLMNs do not have an MCC corresponding to an MCC of the plurality of MCCs included in the list of OPLMNs, wherein storing the prior list of OPLMNs stored on the USIM on the memory is based, at least in part, on the determination.

9. A user equipment device (UE), comprising:

at least one antenna;

at least one radio, wherein the at least one radio is configured to perform cellular communication using at least one radio access technology (RAT); and

one or more processors coupled to the at least one radio, wherein the one or more processors and the at least one radio are configured to perform voice and/or data communications;

wherein the one or more processors are configured to cause the UE to:

receive, from a network, a steering of roaming (SoR) container, wherein the SoR container includes a list of operator preferred public land mobile networks (OPLMNs), and wherein the OPLMNs within the list are associated with a plurality of mobile country codes (MCCs);

compare the list of OPLMNs included in the SoR container to a prior list of OPLMNs;

replace OPLMNs in the prior list of OPLMNs that have an MCC corresponding to an MCC of the plurality of MCCs included in the list of OPLMNs; and

treat, in response to losing a signal to a cell on a visited PLMN (VPLMN), PLMNs in an SoR aborted list as a lower priority than PLMNs stored in a universal subscriber identity module (USIM) of the UE on a memory of the UE.

10. The UE of claim 9 ,

wherein the one or more processors are configured to cause the UE to:

keep OPLMNs in the prior list of OPLMNs that do not have an MCC corresponding to an MCC of the plurality of MCCs included in the list of OPLMNs.

11. The UE of claim 9 ,

wherein the one or more processors are configured to cause the UE to:

store, based, at least in part, on determining that at least a portion of OPLMNs in the prior list of OPLMNs do not have an MCC corresponding to an MCC of the plurality of MCCs included in the list of OPLMNs, the prior list of OPLMNs stored on the USIM of the UE.

12. The UE of claim 9 ,

wherein the one or more processors are configured to cause the UE to:

perform a high priority PLMN selection in which the UE has PLMNs where registration was aborted due to an SoR list; and

treat, during the high priority PLMN selection, equivalent PLMNs in a “PLMNs where registration was aborted due to SoR list” as lower priority than equivalent PLMNs associated with a mobile country code (MCC) equivalent to a MCC of a current serving visited PLMN.

13. The UE of claim 9 ,

wherein the one or more processors are configured to cause the UE to:

add a current PLMN to an SoR aborted list, wherein the SoR aborted list comprises a “registration was aborted due to SoR list”; and

not treat equivalent PLMNs as a lowest priority PLMN based on adding the current PLMN to the SoR aborted list.

14. The UE of claim 9 ,

wherein the one or more processors are configured to cause the UE to:

receive an SoR container while in manual mode or while on a user controlled PLMN; and

remain on a current VPLMN.

15. The UE of claim 9 ,

wherein the one or more processors are configured to cause the UE to:

determine that the UE does not have an OPLMN list or has an OPLMN list with no matching VPLMNs in a current country; and

continue to search for random PLMNs to receive an SoR container.

16. The UE of claim 9 ,

wherein the prior list of OPLMNs is treated as a lower priority list as compared to a list of OPLMNs stored on the USIM.

17. A non-transitory computer readable memory medium storing program instructions executable by processing circuitry to cause a user equipment device (UE) to:

store, while in manual mode of operation, a public land mobile network (PLMN) identity in a steering of roaming (SoR) aborted list;

attempt to obtain service on a higher priority PLMN; and

treat, in response to losing a signal to a cell on a visited PLMN (VPLMN), PLMNs in an SoR aborted list as a lower priority than PLMNs stored in a universal subscriber identity module (USIM) of the UE on a memory of the UE.

18. The non-transitory computer readable memory medium of claim 17 ,

wherein the SoR aborted list includes a “PLMNs where registration was aborted due to SoR list”.

19. The non-transitory computer readable memory medium of claim 17 ,

wherein the program instructions are further executable to:

perform as if a timer that controls periodic attempts has expired; and

send a registration complete message to a serving a core access and mobility management function (AMF).

20. The non-transitory computer readable memory medium of claim 17 ,

wherein the program instructions are further executable to:

fail to replace the prior list of OPLMNs stored on the USIM with the list of OPLMNs included in an SOR container;

store the list of OPLMNs included in the SoR container in memory;

re-attempt to store the list of OPLMNs included in the SoR container on the USIM, wherein the reattempting occurs after expiration of a higher priority PLMN search timer;

receive a retransmission of the SoR container;

determine that contents of the SoR container and contents of the retransmission of the SoR container are the same; and

ignore the retransmission of the SoR container.