Apparatus and method for performing cell activation

1. A method for a user equipment (UE) performing cell activation, the method comprising:

receiving a duplication activation command for a first duplicate radio bearer (RB);

activating duplication for the first duplicate RB based on the duplication activation command; and

activating a first cell mapped to the first duplicate RB if the first cell is deactivated,

wherein a packet data convergence protocol (PDCP) entity of the first duplicate RB submits a duplicated PDCP protocol data unit (PDU) of the first duplicate RB to a RLC entity mapped to the first duplicate RB only after all cells mapped to the first duplicate RB is activated.

2. The method of claim 1 , further comprising:

duplicating the PDCP PDU of the first duplicate RB after cells mapped to the first duplicate RB are activated; and

transmitting the duplicated PDCP PDU of the first duplicate RB using each of the first cell and a second cell, the second cell being mapped to the first duplicate RB.

3. The method of claim 2 , wherein the first duplicate RB includes a first RLC entity and a second RLC entity,

wherein the first RLC entity cell is associated with the first cell, and

wherein the second RLC entity is associated with the second cell.

4. The method of claim 1 , wherein the duplication activation command is received in a duplication MAC control element (duplication MAC CE).

5. The method of claim 1 , further comprising:

re-activating a cell mapped to the first duplicate RB if the cell is activated.

6. The method of claim 1 , further comprising:

receiving a duplication deactivation command for the first duplicate RB;

stopping duplicating of PDCP PDUs of the first duplicate RB; and

maintaining cell activation status of cells mapped to the first duplicate RB.

7. The method of claim 1 , wherein the first cell mapped to the first duplicate RB is activated without receiving a cell activation/deactivation MAC CE.

8. A user equipment (UE) for performing cell activation, the UE comprising: a receiver configured to receive a duplication activation command for a first duplicate radio bearer (RB); and

a processor configured to:

activate duplication for the first duplicate RB based on the duplication activation command;

activate a first cell mapped to the first duplicate RB if the first cell is deactivated; and control a packet data convergence protocol (PDCP) entity of the first duplicate RB to submit a duplicated PDCP protocol data unit (PDU) of the first duplicate RB to a RLC entity mapped to the first duplicate RB only after all cells mapped to the first duplicate RB is activated.

9. The UE of claim 8 , wherein the processor is configured to duplicate the PDCP PDU of the first duplicate RB after cells mapped to the first duplicate RB are activated, further comprising:

a transmitter configured to transmit the duplicated PDCP PDU of the first duplicate RB using each of the first cell and a second cell, the second cell being mapped to the first duplicate RB.

10. The UE of claim 9 , wherein the first duplicate RB includes a first RLC entity and a second RLC entity,

wherein the first RLC entity cell is associated with the first cell, and

wherein the second RLC entity is associated with the second cell.

11. The UE of claim 8 , wherein the processor is configured to re-activate a cell mapped to the first duplicate RB if the cell is activated.

12. The UE of claim 8 , wherein the receiver is configured to receive a duplication deactivation command for the first duplicate RB,

wherein the processor is configured to:

stop duplicating of PDCP PDUs of the first duplicate RB; and

maintain cell activation status of cells mapped to the first duplicate RB.

13. The UE of claim 8 , wherein the first cell mapped to the first duplicate RB is activated without receiving a cell activation/deactivation MAC CE.