Method and apparatus for secondary base station mobility

1. A method of a secondary base station comprising:

establishing a radio link with a UE as a secondary base station for dual connectivity, wherein the radio link comprises a split signaling radio bearer (split SRB);

determining at least one of a cell change or a change of sequence number (SN) at the secondary base station;

transmitting a handover request in response to the determination;

receiving a handover request acknowledge;

forwarding any data for the UE to a target base station based on the handover request acknowledge, wherein the secondary base station refrains from transmitting the data to the UE on the established radio link based on the handover request acknowledge; and

transmitting a radio resource control (RRC) connection reconfiguration based on the handover request acknowledge via the split SRB to a master base station.

2. The method of claim 1 , wherein the RRC connection reconfiguration is transmitted to the UE from the secondary base station.

3. A method of a user equipment (UE) comprising:

establishing a first radio link with a master base station;

establishing a second radio link with a first cell associated with a secondary base station, wherein the second radio link comprises a split signaling radio bearer (split SRB);

receiving a radio resource control (RRC) connection reconfiguration signal from the secondary base station on the second radio link split SRB to establish the second radio link with a second cell associated with a target base station; and

transmitting an RRC connection reconfiguration completion signal based on the RRC connection reconfiguration signal, wherein the RRC connection reconfiguration completion signal is transmitted via an SRB that is determined based on at least one of the split SRB, information received by the UE that configures the SRB, a quality of the first radio link, or a quality of the second radio link.

4. The method of claim 3 , wherein the RRC connection reconfiguration signal is transmitted to a master base station and then the RRC connection reconfiguration signal is transmitted to the UE via one of the first radio link or the second radio link.

5. A method of claim 4 , further comprising:

performing a random access procedure.

6. The method of claim 4 , wherein the RRC connection reconfiguration is received from another secondary base station.

7. The method of claim 4 , wherein the RRC connection reconfiguration is received from a master base station.

8. A method of a secondary base station comprising:

transmitting a change request via a split signaling radio bearer (split SRB) to a master base station;

receiving a change request acknowledge from the master base station;

transmitting a handover request acknowledge associated with a user equipment (UE) to a source base station;

receiving forwarded data for the UE from the source base station based on the handover request acknowledge, wherein the forwarded data is transmitted to the UE after a radio link is established with the UE;

receiving a radio resource control (RRC) reconfiguration complete; and

transmitting a secondary base station change complete.

9. The method of claim 8 , further comprising performing a random access procedure.

10. An apparatus of a secondary base station comprising:

means for establishing a radio link with a UE as a secondary base station for dual connectivity, wherein the radio link comprises a split signaling radio bearer (split SRB);

means for determining at least one of a cell change or a change of sequence number (SN) at the secondary base station;

means for transmitting a handover request in response to the determination;

means for receiving a handover request acknowledge;

means for forwarding any data for the UE to a target base station based on the handover request acknowledge, wherein the apparatus refrains from transmitting the data to the UE on the established radio link based on the handover request acknowledge; and

means for transmitting a radio resource control (RRC) connection reconfiguration based on the handover request acknowledge via the split SRB to a master base station.

11. The apparatus of claim 10 , wherein the RRC connection reconfiguration is transmitted to the UE from the secondary base station.

12. An apparatus of a user equipment (UE) comprising:

means for establishing a first radio link with a master base station;

means for establishing a second radio link with a first cell associated with a secondary base station, wherein the second radio link comprises a split signaling radio bearer (split SRB);

means for receiving a radio resource control (RRC) connection reconfiguration signal from the second radio link split SRB to establish the second radio link with a second cell; and

means for transmitting an RRC connection reconfiguration completion signal based on the RRC connection reconfiguration signal, wherein the RRC connection reconfiguration completion signal is transmitted via an SRB that is determined based on at least one of the split SRB, information received by the UE that configures the SRB, a quality of the first radio link, or a quality of the second radio link.

13. The apparatus of claim 12 , wherein the RRC connection reconfiguration is transmitted to a master base station and then the RRC connection reconfiguration is transmitted to the UE via one of the first radio link or the second radio link.

14. The apparatus of claim 13 , further comprising:

means for performing a random access procedure.

15. The apparatus of claim 13 , wherein the RRC connection reconfiguration is received from another secondary base station.

16. The apparatus of claim 13 , wherein the RRC connection reconfiguration is received from a master base station.

17. An apparatus of a secondary base station comprising:

means for transmitting a change request via a split signaling radio bearer (split SRB) to a master base station;

means for receiving a change request acknowledge from the base station;

means for transmitting a handover request acknowledge associated with a user equipment (UE) to a source base station;

means for receiving forwarded data for the UE from the source base station based on the handover request acknowledge, wherein the forwarded data is transmitted to the UE after a radio link is established with the UE;

means for receiving a radio resource control (RRC) reconfiguration complete; and

means for transmitting a secondary base station change complete.

18. The apparatus of claim 17 , further comprising performing a random access procedure.

19. An apparatus of a secondary base station comprising:

a processing system configured to:

establish a radio link with a UE as a secondary base station for dual connectivity, wherein the radio link comprises a split signaling radio bearer (split SRB);

determine at least one of a cell change or a change of sequence number (SN) at the secondary base station;

transmit a handover request in response to the determination;

receive a handover request acknowledge;

forward any data for the UE to a target base station based on the handover request acknowledge, wherein the apparatus refrains from transmitting the data to the UE on the established radio link based on the handover request acknowledge; and

transmit a radio resource control (RRC) connection reconfiguration based on the handover request acknowledge via the split SRB to a master base station.

20. The apparatus of claim 19 , wherein the RRC connection reconfiguration is transmitted to the UE from the secondary base station.

21. An apparatus of a user equipment (UE) comprising:

a processing system configured to:

establish a first radio link with a master base station;

establish a second radio link with a first cell associated with a secondary base station, wherein the second radio link comprises a split signaling radio bearer (split SRB);

receive a radio resource control (RRC) connection reconfiguration signal from the second radio link split SRB to establish the second radio link with a second cell; and

transmit an RRC connection reconfiguration completion signal based on the RRC connection reconfiguration signal, wherein the RRC connection reconfiguration completion signal is transmitted via an SRB that is determined based on at least one of the split SRB, information received by the UE that configures the SRB, a quality of the first radio link, or a quality of the second radio link.

22. The apparatus of claim 21 , wherein the RRC connection reconfiguration is transmitted to a master base station and then the RRC connection reconfiguration is transmitted to the UE via one of the first radio link or the second radio link.

23. A apparatus of claim 22 , wherein the processing system is further configured to:

perform a random access procedure.

24. The apparatus of claim 22 , wherein the RRC connection reconfiguration is received from another secondary base station.

25. The apparatus of claim 22 , wherein the RRC connection reconfiguration is received from a master base station.

26. An apparatus of a secondary base station comprising:

a processing system configured to:

transmit a change request via a split signaling radio bearer (split SRB) to a master base station;

receive a change request acknowledge from the base station;

transmit a handover request acknowledge associated with a user equipment (UE) to a source base station;

receive forwarded data for the UE from the source base station based on the handover request acknowledge, wherein the forwarded data is transmitted to the UE after a radio link is established with the UE;

receive a radio resource control (RRC) reconfiguration complete; and

transmit a secondary base station change complete.

27. The apparatus of claim 26 , the processing system further configured to perform a random access procedure.

28. A non-transitory, computer-readable medium storing computer-executable code for wireless communication by a base station, comprising code to:

establish a radio link with a UE as a secondary base station for dual connectivity, wherein the radio link comprises a split signaling radio bearer (split SRB);

determine at least one of a cell change or a change of sequence number (SN) at the secondary base station;

transmit a handover request in response to the determination;

receive a handover request acknowledge;

forward any data for the UE to a target base station based on the handover request acknowledge, wherein the apparatus refrains from transmitting the data to the UE on the established radio link based on the handover request acknowledge; and

transmit a radio resource control (RRC) connection reconfiguration based on the handover request acknowledge via the split SRB to a master base station.

29. A non-transitory computer-readable medium storing computer-executable code for wireless communication by a base station, comprising code to:

establish a first radio link with a master base station;

establish a second radio link with a first cell associated with a secondary base station, wherein the second radio link comprises a split signaling radio bearer (split SRB);

receive a radio resource control (RRC) connection reconfiguration signal from the second radio link split SRB to establish the second radio link with a second cell; and

transmit an RRC connection reconfiguration completion signal based on the RRC connection reconfiguration signal, wherein the RRC connection reconfiguration completion signal is transmitted via an SRB that is determined based on at least one of the split SRB, information received by the UE that configures the SRB, a quality of the first radio link, or a quality of the second radio link.

30. A non-transitory computer-readable medium computer-executable code for wireless communication by a base station, comprising code to:

transmit a change request via a split signaling radio bearer (split SRB) to a master base station;

receive a change request acknowledge from the base station;

transmit a handover request acknowledge associated with a user equipment (UE) to a source base station;

receive forwarded data for the UE from the source base station based on the handover request acknowledge, wherein the forwarded data is transmitted to the UE after a radio link is established with the UE;

receive a radio resource control (RRC) reconfiguration complete; and

transmit a secondary base station change complete.