Method and apparatus for controlling redundant data transmission

1. A method for redundantly transmitting data by a user equipment (UE) that configures dual connectivity, the method comprising:

receiving, from an base station, a radio resource control (RRC) message including configuration information for configuring redundant transmission in a packet data convergence protocol (PDCP) entity;

configuring the redundant transmission in the PDCP entity for one or more radio bearers;

receiving, from the base station, instruction information for instructing whether a redundant transmission operation of the configured PDCP entity is activated; and

copying, when the instruction information instructs activation, a PDCP protocol data unit (PDU) in the PDCP entity and transmitting the copied PDCP PDU to different radio link control (RLC) entities to redundantly transmit the same data to a plurality of base stations.

2. The method of claim 1 , wherein the UE is configured to transmit data to and receive data from the plurality of base stations each configured to use a radio access technology different from the other.

3. The method of claim 1 , wherein the instruction information is received through a MAC control element (MAC CE).

4. The method of claim 1 , wherein the receiving the instruction information further includes instructing, by a MAC entity, an upper layer to activate the redundant transmission operation of the PDCP entity when the instruction information instructs activation.

5. The method of claim 1 , wherein, when the instruction information instructs deactivation and the redundant transmission operation of the PDCP entity is configured, the PDCP entity transmits the PDCP PDU to at least one of the plurality of RLC entities.

6. The method of claim 1 , wherein the one or more radio bearers is a data radio bearer (DRB), and the instruction information instructs each of the one or more DRBs to activate or deactivate the redundant transmission operation of the PDCP entity.

7. A method for redundantly receiving by an base station configuring dual connectivity with a user equipment (UE), the method comprising:

transmitting, to the UE, an radio resource control (RRC) message including configuration information for configuring redundant transmission in a packet data convergence protocol (PDCP) entity of the UE for one or more radio bearers;

transmitting instruction information for instructing whether a redundant transmission operation of the configured PDCP entity is activated; and

redundantly receiving data copied in the PDCP entity of the UE and transmitted, through an RLC entity of the base station and an RLC entity of another base station configuring dual connectivity for the UE, when the instruction information instructs activation.

8. The method of claim 7 , wherein the other base station is set to use a radio access technology different from that of the base station, and the dual connectivity is configured with respect to the UE together with the base station.

9. The method of claim 7 , wherein the instruction information is transmitted through a MAC CE.

10. The method of claim 7 , wherein, when the instruction information instructs deactivation and the redundant transmission operation of the PDCP entity is configured in the UE, the PDCP entity of the base station receives data only through the RLC entity of the base station.

11. The method of claim 7 , wherein the one or more radio bearers is a DRB, and the instruction information instructs each of the one or more DRBs to activate or deactivate the redundant transmission operation of the PDCP entity.

12. A User Equipment (UE) of redundantly transmitting data for dual connectivity the UE comprising:

a receiver configured to receive, from an base station, an remote resource control (RRC) message including configuration information for configuring redundant transmission in a packet data convergence protocol (PDCP) entity and to receive instruction information for instructing whether a redundant transmission operation of the PDCP entity configured from the base station is activated or deactivated;

a controller configured to configure the redundant transmission of the PDCP entity for one or more radio bearers; and

a transmitter configured to copy, when the instruction information instructs activation, a PDCP PDU in the PDCP entity and transmit the copied PDCP PDU to different RLC entities to redundantly transmit the same data to a plurality of base stations.

13. The UE of claim 12 , wherein the UE is configured to transmit and receive data to and from the plurality of base stations configured to each use an radio access technology different from the other.

14. The UE of claim 12 , wherein the instruction information is received through a MAC CE.

15. The UE of claim 12 , wherein the controller controls a MAC entity to instruct an upper layer to activate the redundant transmission operation of the PDCP entity, when the instruction information instructs activation.

16. The UE of claim 12 , wherein, when the instruction information instructs deactivation and the redundant transmission operation of the PDCP entity is configured, the PDCP entity transmits the PDCP PDU to at least one of the plurality of RLC entities.

17. The UE of claim 12 , wherein the one or more radio bearers is a DRB, and the instruction information instructs each of the one or more DRBs to activate or deactivate the redundant transmission operation of the PDCP entity.