Method and apparatus for handling sidelink reception in a wireless communication system
A method and apparatus are disclosed. In an example from the perspective of a User Equipment (UE), if sidelink packet duplication is configured or enabled for a Sidelink Radio Bearer (SLRB), a first Packet Data Convergence Protocol (PDCP) Protocol Data Unit (PDU), corresponding to a first PDCP Service Data Unit (SDU), and a duplicate of the first PDCP PDU, are transmitted. A first PDCP Sequence Number (SN) of the first PDCP PDU is set based upon one or more state variables used for sidelink transmission on the SLRB. If the sidelink packet duplication is de-configured or disabled for the SLRB, a second PDCP PDU, corresponding to a second PDCP SDU, is transmitted. Noduplicate of the second PDCP PDU is transmitted. A second PDCP SN of the second PDCP PDU is set based upon the one or more state variables used for sidelink transmission on the SLRB.
1. A method of a User Equipment (UE) for performing sidelink transmission, comprising:
determining whether sidelink packet duplication is (i) configured or enabled for a Sidelink Radio Bearer (SLRB) or (ii) de-configured or disabled for the SLRB according to information included in a system information block;
if a determination is made that the sidelink packet duplication is configured or enabled for the SLRB, transmitting a first Packet Data Convergence Protocol (PDCP) Protocol Data Unit (PDU) corresponding to a first PDCP Service Data Unit (SDU) and a duplicate of the first PDCP PDU, wherein a first PDCP Sequence Number (SN) of the first PDCP PDU is set based upon one or more state variables used for sidelink transmission on the SLRB; and
if a determination is made that the sidelink packet duplication is de-configured or disabled for the SLRB, transmitting a second PDCP PDU corresponding to a second PDCP SDU, wherein a second PDCP SN of the second PDCP PDU is set based upon the one or more state variables used for sidelink transmission on the SLRB and no duplicate of the second PDCP PDU is transmitted.
2. The method of claim 1 , comprising:
maintaining the one or more state variables used for sidelink transmission on the SLRB when the sidelink packet duplication is configured or enabled for the SLRB.
3. The method of claim 2 , comprising:
maintaining the one or more state variables used for sidelink transmission on the SLRB when the sidelink packet duplication is de-configured or disabled for the SLRB.
4. The method of claim 1 , wherein a state variable of the one or more state variables used for sidelink transmission on the SLRB is a Next_PDCP_TX_SN.
5. The method of claim 1 , wherein the second PDCP SN of the second PDCP PDU is not set to 0 when the sidelink packet duplication is de-configured or disabled for the SLRB.
6. The method of claim 4 , wherein a second state variable of the one or more state variables used for sidelink transmission on the SLRB is a TX_HFN.
7. The method of claim 1 , wherein the sidelink packet duplication is configured or enabled if a threshSL-Reliability field of an SL-V2X-PacketDuplicationConfig information element in a system information is set to a value enabling the UE to perform sidelink transmission with the sidelink packet duplication on the SLRB.
8. The method of claim 1 , wherein the sidelink packet duplication is de-configured or disabled if at least one of the following is met:
a threshSL-Reliability field of an SL-V2X-PacketDuplicationConfig information element is not provided to the UE via the system information block;
the threshSL-Reliability field of the SL-V2X-PacketDuplicationConfig information element is removed from the system information block;
the SL-V2X-PacketDuplicationConfig information element is not provided to the UE via the system information block; or
the SL-V2X-PacketDuplicationConfig information element is removed from the system information block.
9. The method of claim 1 , wherein the sidelink packet duplication is de-configured or disabled if a threshSL-Reliability field of an SL-V2X-PacketDuplicationConfig information element in the system information block is changed to a value disabling the UE from performing sidelink transmission with the sidelink packet duplication on the SLRB.
10. The method of claim 1 , wherein:
the first PDCP PDU is transmitted on a first carrier; and
the duplicate of the first PDCP PDU is transmitted on a second carrier, different than the first carrier.
11. A communication device, comprising:
a processor; and
memory comprising processor-executable instructions that when executed by the processor cause performance of operations, the operations comprising:
determining whether sidelink packet duplication is (i) configured or enabled for a Sidelink Radio Bearer (SLRB) or (ii) de-configured or disabled for the SLRB according to information included in a system information block;
if a determination is made that the sidelink packet duplication is configured or enabled for the SLRB, transmitting a first Packet Data Convergence Protocol (PDCP) Protocol Data Unit (PDU) corresponding to a first PDCP Service Data Unit (SDU) and a duplicate of the first PDCP PDU, wherein a first PDCP Sequence Number (SN) of the first PDCP PDU is set based upon one or more state variables used for sidelink transmission on the SLRB; and
if a determination is made that the sidelink packet duplication is de-configured or disabled for the SLRB, transmitting a second PDCP PDU corresponding to a second PDCP SDU, wherein a second PDCP SN of the second PDCP PDU is set based upon the one or more state variables used for sidelink transmission on the SLRB and no duplicate of the second PDCP PDU is transmitted.
12. The communication device of claim 11 , the operations comprising:
maintaining the one or more state variables used for sidelink transmission on the SLRB when the sidelink packet duplication is configured or enabled for the SLRB.
13. The communication device of claim 12 , the operations comprising:
maintaining the one or more state variables used for sidelink transmission on the SLRB when the sidelink packet duplication is de-configured or disabled for the SLRB.
14. The communication device of claim 11 , wherein a state variable of the one or more state variables used for sidelink transmission on the SLRB is a Next_PDCP_TX_SN.
15. The communication device of claim 11 , wherein the second PDCP SN of the second PDCP PDU is not set to 0 when the sidelink packet duplication is de-configured or disabled for the SLRB.
16. The communication device of claim 14 , wherein a second state variable of the one or more state variables used for sidelink transmission on the SLRB is a TX_HFN.
17. The communication device of claim 11 , wherein the sidelink packet duplication is configured or enabled if a threshSL-Reliability field of an SL-V2X-PacketDuplicationConfig information element in the system information block is set to a value enabling the communication device to perform sidelink transmission with the sidelink packet duplication on the SLRB.
18. The communication device of claim 11 , wherein the sidelink packet duplication is de-configured or disabled if at least one of the following is met:
a threshSL-Reliability field of an SL-V2X-PacketDuplicationConfig information element is not provided to the communication device via the system information block;
the threshSL-Reliability field of the SL-V2X-PacketDuplicationConfig information element is removed from the system information block;
the SL-V2X-PacketDuplicationConfig information element is not provided to the communication device via the system information block; or the SL-V2X-PacketDuplicationConfig information element is removed from the system information block.
19. The communication device of claim 11 , wherein the sidelink packet duplication is de-configured or disabled if a threshSL-Reliability field of an SL-V2X-PacketDuplicationConfig information element in the system information block is changed to a value disabling the communication device from performing sidelink transmission with the sidelink packet duplication on the SLRB.
20. The communication device of claim 11 , wherein:
the first PDCP PDU is transmitted on a first carrier; and
the duplicate of the first PDCP PDU is transmitted on a second carrier, different than the first carrier.