Beam-based neighbor relation information

1. A method comprising:

receiving, by a first base station from a second base station, a first message comprising neighbor beam information of a first cell of the second base station, wherein the neighbor beam information comprises:

a neighbor cell identifier of a neighbor cell to the first cell of the second base station, wherein the neighbor cell is associated with a third base station; wherein the third base station is different from the first base station and the second base station;

a first beam index of a first beam of the first cell; and

at least one neighbor beam index of at least one neighbor beam of the first beam of the first cell, wherein the at least one neighbor beam is associated with the neighbor cell of the third base station;

making, by the first base station, a handover decision for a wireless device towards the first cell based on the neighbor beam information; and

transmitting, by the first base station to the second base station, a handover request for the wireless device in response to the handover decision.

2. The method of claim 1 , further comprising transmitting, by the first base station to the second base station, a second message indicating a response to the first message.

3. The method of claim 1 , wherein the second base station receives one or more elements of the neighbor beam information from at least one of:

one or more wireless devices;

one or more base stations;

a core network entity; or

an operation and maintenance entity.

4. The method of claim 1 , wherein the neighbor beam information further comprises at least one of:

one or more first neighbor beam indexes of one or more first neighbor beams of the first cell;

one or more first neighbor cell identifiers of one or more first neighbor cells of the first beam of the first cell;

a frequency offset of at least one of the neighbor cell or the one or more first neighbor cells; or

beam parameters of at least one of the first beam, the at least one neighbor beam, or the one or more first neighbor beams, the beam parameters indicating at least one of:

a synchronization signal block index;

a synchronization signal scheduling information;

a synchronization signal sequence information;

a reference signal index;

a reference signal scheduling information;

a reference signal sequence information; or

beam configuration parameters.

5. The method of claim 1 , wherein the first message comprises one of:

an Xn setup request message; or

a gNB configuration update message.

6. The method of claim 1 , further comprising determining, by the first base station, neighbor relation information based on the neighbor beam information of the first cell, wherein the neighbor relation information comprises neighboring relations of a plurality of beams and a plurality of cells.

7. The method of claim 6 , further comprising transmitting, by the first base station to an operation and maintenance entity, the neighbor relation information.

8. The method of claim 6 , further comprising transmitting, by the first base station to a fourth base station, a third message based on the neighbor relation information, the third message indicating a request of at least one of:

a handover towards a cell of the third base station;

a multi connectivity initiation;

a secondary base station modification;

a direct interface setup; or

a mobility setting change.

9. The method of claim 8 , wherein the fourth base station is the second base station.

10. A base station comprising:

one or more processors; and

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

receive, from a second base station, a first message comprising neighbor beam information of a first cell of the second base station, wherein the neighbor beam information comprises:

a neighbor cell identifier of a neighbor cell to the first cell of the second base station, wherein the neighbor cell is associated with a third base station; wherein the third base station is different from the base station and the second base station;

a first beam index of a first beam of the first cell; and

at least one neighbor beam index of at least one neighbor beam of the first beam of the first cell, wherein the at least one neighbor beam is associated with the neighbor cell of the third base station;

make a handover decision for a wireless device towards the first cell based on the neighbor beam information; and

transmit, to the second base station, a handover request for the wireless device in response to the handover decision.

11. The base station of claim 10 , wherein the instructions, when executed by the one or more processors, further cause the base station to transmit, to the second base station, a second message indicating a response to the first message.

12. The base station of claim 10 , wherein the second base station receives one or more elements of the neighbor beam information from at least one of:

one or more wireless devices;

one or more base stations;

a core network entity; or

an operation and maintenance entity.

13. The base station of claim 10 , wherein the neighbor beam information further comprises at least one of:

one or more first neighbor beam indexes of one or more first neighbor beams of the first cell;

one or more first neighbor cell identifiers of one or more first neighbor cells of the first beam of the first cell;

a frequency offset of at least one of the neighbor cell or the one or more first neighbor cells; or

beam parameters of at least one of the first beam, the at least one neighbor beam, or the one or more first neighbor beams, the beam parameters indicating at least one of:

a synchronization signal block index;

a synchronization signal scheduling information;

a synchronization signal sequence information;

a reference signal index;

a reference signal scheduling information;

a reference signal sequence information; or

beam configuration parameters.

14. The base station of claim 10 , wherein the first message comprises one of: an Xn setup request message; or

a gNB configuration update message.

15. The base station of claim 10 , wherein the instructions, when executed by the one or more processors, further cause the base station to determine neighbor relation information based on the neighbor beam information of the first cell, wherein the neighbor relation information comprise neighboring relations of a plurality of beams and a plurality of cells.

16. The base station of claim 15 , wherein the instructions, when executed by the one or more processors, further cause the base station to transmit, to an operation and maintenance entity, the neighbor relation information.

17. The base station of claim 15 , wherein the instructions, when executed by the one or more processors, further cause the base station to transmit, to a fourth base station, a third message based on the neighbor relation information, the third message indicating a request of at

least one of:

a handover towards a cell of the third base station;

a multi connectivity initiation;

a secondary base station modification;

a direct interface setup; or

a mobility setting change.

18. The base station of claim 17 , wherein the fourth base station is the second base station.

19. A method comprising:

sending, by a second base station to a first base station, a first message comprising neighbor beam information of a first cell of the second base station, wherein the neighbor beam information comprises:

a neighbor cell identifier of a neighbor cell to the first cell of the second base station, wherein the neighbor cell is associated with a third base station; wherein the third base station is different from the first base station and the second base station;

a first beam index of a first beam of the first cell; and

at least one neighbor beam index of at least one neighbor beam of the first beam of the first cell, wherein the at least one neighbor beam is associated with the neighbor cell of the third base station;

receiving, by the second base station from the first base station, a second message indicating a response to the first message; and

receiving, by the second base station from the first base station, a handover request for a handover of a wireless device towards the first cell based on the neighbor beam information.

20. The method of claim 19 , wherein the second base station receives one or more elements of the neighbor beam information from at least one of:

one or more wireless devices;

one or more base stations;

a core network entity; or

an operation and maintenance entity.