Methods for packet data convergence protocol (PDCP) duplication operations and devices using the same

1. A method for wireless communications, the method comprising:

receiving, by a communication device, duplication assistance information from a network, the communication device being configured with a Packet Data Convergence Protocol (PDCP) duplication function and a plurality of Radio Link Control (RLC) entities including a first RLC entity and a second RLC entity;

duplicating, by a PDCP entity of the communication device, a first PDCP Protocol Data Unit (PDU) to create a second PDCP PDU that is a copy of the first PDCP PDU;

providing, by the PDCP entity of the communication device, the first PDCP PDU and the second PDCP PDU to the first RLC entity and the second RLC entity, respectively;

discarding, by the communication device, the second PDCP PDU in a buffer of the second RLC entity based on the duplication assistance information when the PDCP duplication function is activated; and

minimizing, by the PDCP entity of the communication device, a PDCP Sequence Number (SN) gap between the first RLC entity and the second RLC entity.

2. The method of claim 1 , wherein the duplication assistance information comprises a PDCP PDU discard timer configured for the second RLC entity.

3. The method of claim 1 , wherein the duplication assistance information comprises PDCP SN gap information that indicates a difference between a first PDCP SN of a first PDCP PDU received by a first network node in the network and a second PDCP SN of a second PDCP PDU received by a second network node in the network.

4. The method of claim 2 , further comprising:

discarding, by the communication device, the second PDCP PDU when the PDCP PDU discard timer expires.

5. The method of claim 1 , wherein the duplication assistance information is included in a PDCP control PDU.

6. The method of claim 1 , further comprising:

receiving, by the communication device, duplication control information from the network, the duplication control information being configured to switch a status of the PDCP duplication function of at least one radio bearer; and

transmitting, by the communication device, a duplication status report to the network.

7. The method of claim 6 , wherein the duplication status report comprises at least one Last Sequence Number (LSN) indicating a PDCP SN of a last PDCP PDU of the at least one radio bearer before the status of the PDCP duplication function is switched in response to the duplication control information.

8. The method of claim 6 , wherein the duplication status report is included in a PDCP control PDU or a Medium Access Control (MAC) Control Element (CE).

9. The method of claim 6 , wherein the duplication status report is transmitted in response to a change of the status of the PDCP duplication function.

10. A communication device configured with a Packet Data Convergence Protocol (PDCP) duplication function and a plurality of Radio Link Control (RLC) entities including a first RLC entity and a second RLC entity, the communication device comprising:

one or more non-transitory computer-readable media having computer-executable instructions embodied thereon; and

at least one processor coupled to the one or more non-transitory computer-readable media, and configured to execute the computer-executable instructions to:

receive duplication assistance information from a network;

duplicate a first PDCP Protocol Data Unit (PDU) to create a second PDCP PDU that is a copy of the first PDCP PDU;

provide the first PDCP PDU and the second PDCP PDU to the first RLC entity and the second RLC entity, respectively;

discard the second PDCP PDU in a buffer of the second RLC entity based on the duplication assistance information when the PDCP duplication function is activated; and

minimize a PDCP Sequence Number (SN) gap between the first RLC entity and the second RLC entity.

11. The communication device of claim 10 , wherein the duplication assistance information comprises a PDCP PDU discard timer configured for the second RLC entity.

12. The communication device of claim 10 , wherein the duplication assistance information comprises PDCP Sequence Number (SN) SN gap information that indicates a difference between a first PDCP SN of a first PDCP PDU received by a first network node in the network and a second PDCP SN of a second PDCP PDU received by a second network node in the network.

13. The communication device of claim 11 , wherein the at least one processor is further configured to execute the computer-executable instructions to:

discard the second PDCP PDU when the PDCP PDU discard timer expires.

14. The communication device of claim 10 , wherein the duplication assistance information is included in a PDCP control PDU.

15. The communication device of claim 10 , wherein the at least one processor is further configured to execute the computer-executable instructions to:

receive duplication control information from the network, the duplication control information being configured to switch a status of the PDCP duplication function of at least one radio bearer; and

transmit a duplication status report to the network.

16. The communication device of claim 15 , wherein the duplication status report comprises at least one Last Sequence Number (LSN) indicating a PDCP SN of a last PDCP PDU of the at least one radio bearer before the status of the PDCP duplication function is switched in response to the duplication control information.

17. The communication device of claim 15 , wherein the duplication status report is included in a PDCP control PDU or a Medium Access Control (MAC) Control Element (CE).

18. The communication device of claim 15 , wherein the duplication status report is transmitted in response to a change of the status of the PDCP duplication function.