Method for Synchronizing Encryption Information Between Scell and Ue

1. A method by a first base station in a wireless communication system, the method comprising: receiving, from a second base station, a first message including a first count value associated with a radio bearer established for a terminal; transmitting, to the terminal, a second message including the first count value received from the second base station; receiving, from the terminal, a response message in response to the second message, the response message including a second count value associated with the radio bearer; and performing further action based on the first count value and the second count value.

2. The method of claim 1, wherein the further action comprises: transmitting, to the terminal, a third message for releasing a radio connection between the terminal and the second base station.

3. The method of claim 1, wherein the further action comprises: transmitting, to the second base station, a fourth message to release a resource of the terminal.

4. The method of claim 1, wherein the second count value is not identical to the first count value included in the second message.

5. The method of claim 1, further comprising: determining whether the first count value reaches a predefined threshold; and transmitting, to the second base station, a fifth message to request to release the first count value, reconfigure the first count value or perform another operation, if the first count value reaches the predefined threshold.

6. The method of claim 2, further comprising: determining whether the first count value and the second count value are identical; and releasing the radio connection and transmitting a sixth message, to the second base station, to request the second base station for releasing information of the terminal saved by the second base station, if the first count value and the second count value are not identical.

7. The method of claim 1, further comprising: transmitting, to the second base station, the second count value received from the terminal.

8. The method of claim 6, further comprising: requesting to release a radio resource control connection of the terminal, if the first count value and the second count value are not identical.

9. The method of claim 5, further comprising: receiving, from the second base station, a seventh message to request to release the first count value, reconfigure the first count value, or perform another operation, if the first count value reaches the predefined threshold.

10. The method of claim 1, wherein the first message is periodically transmitted by the second base station or the first message is transmitted by the second base station according to a configured threshold.

11. The method of claim 1, wherein the first base station receives the first count value from the second base station after transmitting, to the second base station, a eighth message of the first count value.

12. The method of claim 11, wherein the eighth message of the first count value comprises a cell identity of the second base station, and wherein the method further comprises: receiving, from the second base station, count values of all radio bearers established by the second base station for the terminal, if the eighth message of the first count value does not comprise an identity of the radio bearer established for the terminal.

13. An apparatus of a first base station for in a wireless communication system, the apparatus comprising: a transceiver; and a controller coupled with the transceiver and configured to control to: receive, from a second base station, a first message including a first count value associated with a radio bearer established for a terminal, transmit, to the terminal, a second message including the first count value received from the second base station, receive, from the terminal, a response message in response to the second message, the response message including a second count value associated with the radio bearer, and perform further action based on the first count value and the second count value.

14. The apparatus of claim 13, wherein the further action comprises: transmit, to the terminal, a third message for releasing a radio connection between the terminal and the second base station.

15. The apparatus of claim 13, wherein the further action comprises: transmit, to the second base station, a fourth message to release a resource of the terminal.

16. The apparatus of claim 13, wherein the second count value is not identical to the first count value included in the second message.

17. The apparatus of claim 13, wherein the controller is further configured to: determine whether the first count value reaches a predefined threshold, and transmit, to the second base station, a fifth message to request to release the first count value, reconfigure the first count value, or perform another operation, if the first count value reaches the predefined threshold.

18. The apparatus of claim 14, wherein the controller is further configured to: determine whether the first count value and the second count value are identical, and release the radio connection and transmit a sixth message, to the second base station, to request the second base station for releasing information of the terminal saved by the second base station, if the first count value and the second count value are not identical.

19. The apparatus of claim 13, wherein the controller is further configured to: transmit, to the second base station, the second count value.

20. The apparatus of claim 18, wherein the controller is further configured to: request to release a radio resource control connection of the terminal if the first count value and the second count value are not identical.

21. The apparatus of claim 17, wherein the controller is further configured to: receive, from the second base station, a seventh message to request to release the first count value, reconfigure the first count value, or perform another operation, if the first count value reaches the predefined threshold.

22. The apparatus of claim 13, wherein the first message is periodically transmitted by the second base station or the first message is transmitted by the second base station based on a configured threshold.

23. The apparatus of claim 13, wherein the controller is further configured to: receive the first count value from the second base station after transmitting, to the second base station, a eighth message of the first count value.

24. The apparatus of claim 23, wherein the eighth message of the first count value comprises a cell identity of the second base station, and wherein, if the eighth message of the first count value does not comprise an identity of the radio bearer established for the terminal, the controller is further configured to: receive, from the second base station, count values of all radio bearers established by the second base station for the terminal.

25. A method performed by a first base station, the method comprising: transmitting, to a second base station, a request message for adding at least one cell associated with the second base station for a user equipment (UE), wherein the request message is for the UE to communicate with both the first base station and the second base station; receiving, from the second base station, a response message as a response to the request message; receiving, from the second base station, a first message including first count values associated with a radio bearer established for the UE, wherein the first count values include an uplink count value and a downlink count value; transmitting, to the UE, a second message including highest 25 bits of the uplink count value and highest 25 bits of the downlink count value obtained from the first count values; receiving, from the UE, a third message as a response to the second message; identifying that the third message includes second count values associated with the radio bearer, wherein the second count values are different from the first count values; and releasing a radio connection associated with the UE based on the third message including the second count value associated with the radio bearer.

26. The method of claim 25, further comprising: determining whether the first count values associated with the radio bearer reach a predefined threshold.

27. The method of claim 28, further comprising: transmitting, to the second base station, a fifth message for releasing a resource associated with the UE.

28. The method of claim 25, wherein the first message is periodically received from the second base station or the first message is received from the second base station based on a configured condition.

29. A method performed by a user equipment (UE), the method comprising: receiving, from a first base station, a first message including highest 25 bits of an uplink count value and highest 25 bits of a downlink count value obtained from first count values, associated with a radio bearer established for the UE, wherein the first count values include the uplink count value and the downlink count value; transmitting, to the first base station, a second message including second count values associated with the radio bearer as a response to the first message; and receiving, from the first base station, a third message for releasing a radio connection associated with the UE, based on the second message including the second count values being different from the first count values, wherein the UE is in communication with both the first base station and a second base station based on a request message for adding at least one cell associated with the second base station for the UE.