Method and apparatus for PLMN selection and cell (re)selection

1. A User Equipment (UE) for wireless communications, the UE comprising:

one or more non-transitory computer-readable media storing one or more computer-executable instructions; and

at least one processor coupled to the one or more non-transitory computer-readable media, and configured to execute the one or more computer-executable instructions to:

read system information of a plurality of cells on a first carrier frequency to obtain identification information of a plurality of Public Land Mobile Networks (PLMNs);

report, by an Access Stratum (AS) entity of the UE, the identification information of the plurality of PLMNs to a Non-Access Stratum (NAS) entity of the UE;

select, by the NAS entity of the UE, one of the plurality of PLMNs as a selected PLMN;

search for the plurality of cells on the first carrier frequency during a cell selection procedure; and

select a suitable cell belonging to the selected PLMN from the plurality of cells on the first carrier frequency based on the cell selection procedure.

2. The UE of claim 1 , wherein the at least one processor is further configured to execute the one or more computer-executable instructions to:

perform a cell reselection procedure to select a new suitable cell,

wherein the new suitable cell is a non-highest-ranked cell among the plurality of cells on the first carrier frequency and belongs to one of the selected PLMN, a registered PLMN, and a PLMN that is indicated as being equivalent to the registered PLMN of the UE.

3. The UE of claim 2 , wherein the non-highest-ranked cell and a highest-ranked cell of the plurality of cells on the first carrier frequency belong to two PLMNs of the plurality of PLMNs.

4. The UE of claim 1 , wherein the at least one processor is further configured to execute the one or more computer-executable instructions to:

perform a cell reselection procedure to select a new suitable cell, the cell reselection procedure comprising:

determining whether the new suitable cell is on a second carrier frequency after determining that a total number of non-suitable cells of the plurality of cells on the first carrier frequency reaches a specific number.

5. The UE of claim 4 , wherein the cell reselection procedure further comprises:

selecting, from one or more cells on the second carrier frequency, a highest-ranked cell as the new suitable cell when the highest-ranked cell belongs to one of the selected PLMN, a registered PLMN, a PLMN that is indicated as being equivalent to the registered PLMN of the UE;

determining that the highest-ranked cell is a non-suitable cell when the highest-ranked cell does not belong to one of the selected PLMN, the registered PLMN, and the PLMN that is indicated as being equivalent to the registered PLMN of the UE; and

prohibiting the non-suitable cell from being selected as the new suitable cell for a period of time.

6. The UE of claim 5 , wherein the cell reselection procedure further comprises:

determining the highest-ranked cell by ranking the one or more cells on the second carrier frequency based on a received radio signal quality.

7. The UE of claim 4 , wherein the at least one processor is further configured to execute the one or more computer-executable instructions to:

deprioritize the first carrier frequency for cell reselection for a period of time after determining that the total number of non-suitable cells of the plurality of cells on the first carrier frequency reaches the specific number.

8. The UE of claim 1 , wherein the system information includes PLMN-type information indicating at least one PLMN type associated with the plurality of cells.

9. The UE of claim 1 , wherein the at least one processor is further configured to execute the one or more computer-executable instructions to:

provide a message by the NAS entity of the UE to the AS entity of the UE, the message indicating which of one or more PLMN types are supported by the UE,

wherein the one or more PLMN types include a public PLMN type, a private PLMN type, and a public and private PLMN type.

10. The UE of claim 1 , wherein the first carrier frequency is an unlicensed carrier frequency.

11. A method performed by a User Equipment (UE) for wireless communications, the method comprising:

reading system information of a plurality of cells on a first carrier frequency to obtain identification information of a plurality of Public Land Mobile Networks (PLMNs);

reporting, by an Access Stratum (AS) entity of the UE, the identification information of the plurality of PLMNs to a Non-Access Stratum (NAS) entity of the UE;

selecting, by the NAS entity of the UE, one of the plurality of PLMNs as a selected PLMN;

searching for the plurality of cells on the first carrier frequency during a cell selection procedure; and

selecting a suitable cell belonging to the selected PLMN from the plurality of cells on the first carrier frequency based on the cell selection procedure.

12. The method of claim 11 , further comprising:

performing a cell reselection procedure to select a new suitable cell,

wherein the new suitable cell is a non-highest-ranked cell among the plurality of cells on the first carrier frequency and belongs to one of the selected PLMN, a registered PLMN, and a PLMN that is indicated as being equivalent to the registered PLMN of the UE.

13. The method of claim 12 , wherein the non-highest-ranked cell and a highest-ranked cell of the plurality of cells on the first carrier frequency belong to two PLMNs of the plurality of PLMNs.

14. The method of claim 11 , further comprising:

performing a cell reselection procedure to select a new suitable cell, the cell reselection procedure comprising:

determining whether the new suitable cell is on a second carrier frequency after determining that a total number of non-suitable cells of the plurality of cells on the first carrier frequency reaches a specific number.

15. The method of claim 14 , wherein the cell reselection procedure further comprises:

selecting, from one or more cells on the second carrier frequency, a highest-ranked cell as the new suitable cell when the highest-ranked cell belongs to one of the selected PLMN, a registered PLMN, and a PLMN that is indicated as being equivalent to the registered PLMN of the UE;

determining that the highest-ranked cell is a non-suitable cell when the highest-ranked cell does not belong to one of the selected PLMN, the registered PLMN, and the PLMN that is indicated as being equivalent to the registered PLMN of the UE; and

prohibiting the non-suitable cell from being selected as the new suitable cell for a period of time.

16. The method of claim 15 , wherein the cell reselection procedure further comprises:

determining the highest-ranked cell by ranking the one or more cells on the second carrier frequency based on a received radio signal quality.

17. The method of claim 14 , further comprising:

deprioritizing the first carrier frequency for cell reselection for a period of time after determining that the total number of non-suitable cells of the plurality of cells on the first carrier frequency reaches the specific number.

18. The method of claim 11 , wherein the system information includes PLMN-type information indicating at least one PLMN type associated with the plurality of cells.

19. The method of claim 11 , further comprising:

providing a message by the NAS entity of the UE to the AS entity of the UE, the message indicating which of one or more PLMN types are supported by the UE,

wherein the one or more PLMN types include a public PLMN type, a private PLMN type, and a public and private PLMN type.

20. The method of claim 11 , wherein the first carrier frequency is an unlicensed carrier frequency.