Data transmission method performed by base station in wireless communication system, and apparatus using same

1. A data transfer method performed by a first base station in a wireless communication system, the method comprising:

transmitting, to a second base station, a message requesting information for data transfer, wherein the message includes an identity (ID) related to a user equipment (UE);

receiving, from the second base station, a response message to the message requesting the information for data transfer, wherein the response message informs the first base station that the second base station will provide the first base station data related to the UE;

transmitting, to the second base station, address information for the second base station; and

receiving, from the second base station, the data related to the UE pending at the second base station based on the address information for the second base station,

wherein the first base station informs the second base station, by the address information for the second base station, of resource contexts to which the data, related to the UE pending at the second base station, can be transferred to the first base station.

2. The method of claim 1 , wherein the UE is in a light connection state, such that an RRC (Radio Resource Control) connection with the second base station is deactivated, a connection state with a CN (Core Network) is maintained, and the second base station and the UE store a UE context of the UE.

3. The method of claim 2 , wherein the first base station transfers data for the UE to the second base station.

4. The method of claim 1 , wherein information requested by the message requesting information for data transfer is a downlink GTP (GPRS Tunneling Protocol) tunnel endpoint IE (Information Element).

5. The method of claim 1 , wherein the message requesting information for data transfer comprises at least one of an E-RAB (E-UTRAN Radio Access Bearer) ID (Identity) and an E-RAB level QoS (Quality of Service) parameter IE (Information Element).

6. The method of claim 1 , wherein the response message to the message requesting information for data transfer, from the second base station, comprises a downlink GTP (GPRS tunneling protocol) tunnel endpoint IE (information element).

7. The method of claim 6 , wherein the downlink GTP tunnel endpoint IE comprises information that informs the first base station of a path for data transfer between the second base station and a P-GW (PDN-Gateway).

8. The method of claim 1 , wherein the first base station transmits a paging request to the second base station.

9. The method of claim 8 , wherein based on a UE being located inside a coverage area of the second base station, a paging response message including an ID (Identity) of the UE is received from the second base station.

10. A base station comprising:

a transceiver for transmitting and receiving a radio signal; and

a processor operatively coupled to the transceiver,

wherein the processor is configured to:

transmit, via the transceiver, to a second base station, a message requesting information for data transfer, wherein the message includes an identity (ID) related to a user equipment (UE),

receive, via the transceiver, from the second base station, a response message to the message requesting the information for data transfer, wherein the response message informs the first base station that the second base station will provide the first base station data related,

transmit, via the transceiver, to the second base station, address information for the second base station, and

receive, via the transceiver, from the second base station, the data related to the UE pending at the second base station based on the address information for the second base station,

wherein the first base station informs the second base station, by the address information for the second base station, of resource contexts to which the data, related to the UE pending at the second base station, can be transferred to the first base station.

11. The base station of claim 10 , wherein the UE is in a light connection state, such that an RRC (Radio Resource Control) connection with the second base station is deactivated, a connection state with a CN (Core Network) is maintained, and the second base station and the UE store a UE context of the UE.

12. The base station of claim 11 , wherein the first base station transfers data for the UE to the second base station.

13. The base station of claim 10 , wherein information requested by the message requesting information for data transfer is a downlink GTP (GPRS Tunneling Protocol) tunnel endpoint IE (Information Element).

14. The base station of claim 10 , wherein the message requesting information for data transfer comprises at least one of an E-RAB (E-UTRAN Radio Access Bearer) ID (Identity) and an E-RAB level QoS (Quality of Service) parameter IE (Information Element).

15. The base station of claim 10 , wherein the response message to the message requesting information for data transfer, from the second base station, comprises a downlink GTP (GPRS tunneling protocol) tunnel endpoint IE (information element).

16. The base station of claim 15 , wherein the downlink GTP tunnel endpoint IE comprises information that informs the first base station of a path for data transfer between the second base station and a P-GW (PDN-Gateway).

17. The base station of claim 10 , wherein the first base station transmits a paging request to the second base station.

18. The base station of claim 17 , wherein based on a UE being located inside a coverage area of the second base station, a paging response message including an ID (Identity) of the UE is received from the second base station.

19. An apparatus in a wireless communication, the apparatus comprising:

a processor; and

a memory coupled to the processor,

wherein the processor is configured to:

transmit, via the transceiver, to a second base station, a message requesting information for data transfer, wherein the message includes an identity (ID) related to a user equipment (UE),

receive, via the transceiver, from the second base station, a response message to the message requesting the information for data transfer, wherein the response message informs the first base station that the second base station will provide the first base station data related to the UE,

transmit, via the transceiver, to the second base station, address information for the second base station, and

receive, via the transceiver, from the second base station, the data related to the UE pending at the second base station based on the address information for the second base station,

wherein the first base station informs the second base station, by the address information for the second base station, of resource contexts to which the data, related to the UE pending at the second base station, can be transferred to the first base station.