Handover for closed access group

1. A method comprising:

receiving, by a first base station from a second base station, a next generation radio access network (NG-RAN) configuration update message comprising parameters of one or more cells of the second base station, wherein the parameters indicate:

a neighbor information evolved universal mobile telecommunications system terrestrial radio access (E-UTRA) information element (IE); and

a served cells new radio (NR) to add IE comprising:

a slice identifier of a first network slice supported by a cell of the one or more cells of the second base station; and

an NR physical cell identifier (NR-PCI) of the cell;

sending, by the first base station to the second base station, in response to receiving the served cells NR to add IE, an NG-RAN configuration update acknowledge message comprising a served cell information NR IE indicating that the cell is in a first closed access group (CAG);

receiving, by the first base station from a wireless device, one or more messages comprising:

an identifier of the cell of the second base station;

a measurement report of a signal strength for the cell;

a slice identifier of the first network slice; and

an indication that the wireless device is allowed to access the first CAG;

determining, by the first base station, to send a handover request message for handover of the wireless device to the first cell of the second base station based on:

the measurement report received from the wireless device; and

the cell being in the first CAG; and

sending, to the second base station, the handover request message, wherein the handover request message comprises an identifier of the cell.

2. The method of claim 1 , further comprising selecting, by the first base station, the second base station based on the parameters.

3. The method of claim 1 , wherein the NG-RAN configuration update message further comprises mapping information of the slice identifier to one or more CAGs.

4. The method of claim 1 , further comprising receiving, by the first base station, a radio resource control (RRC) message mapping information for one or more slice identifiers associated with the first CAG.

5. The method of claim 1 , further comprising receiving, by the first base station, a radio resource control (RRC) message comprising a default configured slice identifier indication for the first CAG.

6. The method of claim 1 , further comprising receiving, by the first base station, from an access and mobility management function (AMF), a context setup request comprising:

mapping information for one or more slice identifiers associated with the first CAG; or

a default configured slice identifier indication for the first CAG.

7. The method of claim 1 , wherein the served cell information NR IE comprises a list of CAG identifiers that one or more cells of the first base station support.

8. The method of claim 1 , wherein the NG-RAN configuration update acknowledge message comprises a network slice configuration parameter associated with a CAG that one or more cells of the first base station support.

9. The method of claim 1 , wherein the handover request message comprises context information of the wireless device, wherein the context information of the wireless device comprises:

a CAG restriction indicator; and

an identifier of the first CAG.

10. The method of claim 1 , wherein the first CAG is associated with a non-public network.

11. A first base station comprising:

one or more processors;

memory storing instructions that, when executed by the one or more processors, cause the first base station to:

receive, from a second base station, a next generation radio access network (NG-RAN) configuration update message comprising parameters of one or more cells of the second base station, wherein the parameters indicate:

a neighbor information evolved universal mobile telecommunications system terrestrial radio access (E-UTRA) information element (IE); and

a served cells new radio (NR) to add IE comprising:

a slice identifier of a first network slice supported by a cell of the one or more cells of the second base station; and

an NR physical cell identifier (NR-PCI) of the cell;

send, to the second base station, in response to receiving the served cells NR to add IE, an NG-RAN configuration update acknowledge message comprising a served cell information NR IE indicating that the cell is in a first closed access group (CAG);

receive, from a wireless device, one or more messages comprising:

an identifier of the cell of the second base station;

a measurement report of a signal strength for the cell;

a slice identifier of the first network slice; and

an indication that the wireless device is allowed to access the first CAG;

determine, by the first base station, to send a handover request message for handover of the wireless device to the cell of the second base station based on:

the measurement report received from the wireless device; and

the cell being in the first CAG; and

send, to the second base station, the handover request message, wherein the handover request message comprises an identifier of the cell.

12. The first base station of claim 11 , wherein the instructions, when executed by the one or more processors, further cause the first base station to select the second base station based on the parameters.

13. The first base station of claim 11 , wherein the NG-RAN configuration update message further comprises mapping information of the slice identifier to one or more CAGs.

14. The first base station of claim 11 , wherein the instructions, when executed by the one or more processors, further cause the first base station to receive a radio resource control (RRC) message mapping information for one or more slice identifiers associated with the first CAG.

15. The first base station of claim 11 , wherein the instructions, when executed by the one or more processors, further cause the first base station to receive a radio resource control (RRC) message comprising a default configured slice identifier indication for the first CAG.

16. The first base station of claim 11 , wherein the instructions, when executed by the one or more processors, further cause the first base station to receive, from an access and mobility management function (AMF), a context setup request comprising:

mapping information for one or more slice identifiers associated with the first CAG; or

a default configured slice identifier indication for the first CAG.

17. The first base station of claim 11 , wherein the served cell information NR IE comprises a list of CAG identifiers that one or more cells of the first base station support.

18. The first base station of claim 11 , wherein the NG-RAN configuration update acknowledge message comprises a network slice configuration parameter associated with a CAG that one or more cells of the first base station support.

19. The first base station of claim 11 , wherein the handover request message comprises context information of the wireless device, wherein the context information of the wireless device comprises:

a CAG restriction indicator; and

an identifier of the first CAG.

20. A system comprising:

a first base station comprising:

one or more first processors;

a first memory storing first instructions that, when executed by the one or more first processors, cause the first base station to:

receive, from a second base station, a next generation radio access network (NG-RAN) configuration update message comprising parameters of one or more cells of the second base station, wherein the parameters indicate:

a neighbor information evolved universal mobile telecommunications system terrestrial radio access (E-UTRA) information element (IE); and

a served cells new radio (NR) to add IE comprising:

a slice identifier of a first network slice supported by a cell of the one or more cells of the second base station; and

an NR physical cell identifier (NR-PCI) of the cell;

send, to the second base station, in response to receiving the served cells NR to add IE, an NG-RAN configuration update acknowledge message comprising a served cell information NR IE indicating that the cell is in a first closed access group (CAG);

receive, from a wireless device, one or more messages comprising:

an identifier of the cell of the second base station;

a measurement report of a signal strength for the cell;

a slice identifier of the first network slice; and

an indication that the wireless device is allowed to access the first CAG;

determine, by the first base station, to send a handover request message for handover of the wireless device to the cell of the second base station based on:

the measurement report received from the wireless device; and

the cell being in the first CAG; and

send, to the second base station, the handover request message, wherein the handover request message comprises an identifier of the cell; and

the second base station, wherein the second base station comprises:

one or more second processors;

a second memory storing second instructions that, when executed by the one or more second processors, cause the second base station to:

send, to the first base station, the NG-RAN configuration update message comprising the parameters;

receive, from the first base station, the NG-RAN configuration update acknowledge message; and

receive, from the first base station, the handover request message.