METHOD AND APPARATUS FOR TRANSMITTING PACKET IN WIRELESS COMMUNICATION SYSTEM
A method, performed by a terminal, of transmitting and receiving a signal in a wireless communication system is provided. The method includes setting a value of a Next_Packet Data Convergence Protocol (PDCP)_RX_sequence number (SN) variable as an initial value, the Next_PDCP_RX_SN variable indicating a predicted SN of PDCP data to be received, receiving first PDCP data from a transmission entity after setting the initial value, and setting the value of the Next_PDCP_RX_SN variable as a value obtained by adding a first setting value to a value of the SN of the PDCP data.
1 . A method, performed by a terminal, of transmitting and receiving a signal in a wireless communication system, the method comprising:
setting a value of a Next_Packet Data Convergence Protocol (PDCP)_RX_sequence number (SN) variable as an initial value, the Next_PDCP_RX_SN variable indicating a predicted SN of PDCP data to be received;
receiving first PDCP data from a transmission entity after setting the initial value; and
setting the value of the Next_PDCP_RX_SN variable as a value obtained by adding a first setting value to a value of the SN of the first PDCP data.
2 . The method of claim 1 , wherein the first setting value is 1.
3 . The method of claim 1 , further comprising:
setting a value of a Last_Submitted_PDCP_RX_SN variable, which indicates an SN of PDCP data most recently transferred to an upper layer, as a value obtained by subtracting a second setting value from a value of the SN of the first PDCP data.
4 . The method of claim 3 , further comprising:
starting a PDCP reordering timer based on the value of the Next_PDCP_RX_SN variable and the value of the Last_Submitted_PDCP_RX_SN variable.
5 . The method of claim 4 , further comprising:
setting a value of a Reordering_PDCP_RX_COUNT variable by using the value of the Next_PDCP_RX_SN variable, the Reordering_PDCP_RX_COUNT variable being used by the PDCP reordering timer.
6 . The method of claim 1 , wherein the PDCP data is transmitted from the transmission entity by using a vehicle-to-everything (V2X) communication scheme.
7 . A terminal for transmitting and receiving a signal in a wireless communication system, the terminal comprising:
a transceiver; and
at least one processor configured to:
set a value of a Next_Packet Data Convergence Protocol (PDCP)_RX_sequence number (SN) variable as an initial value, the Next_PDCP_RX_SN variable indicating a predicted SN of PDCP data to be received,
receive, from a transmission entity via the transceiver, first PDCP data after setting the initial value, and
set the value of the Next_PDCP_RX_SN variable as a value obtained by adding a first setting value to a value of the SN of the first PDCP data.
8 . The terminal of claim 7 , wherein the first setting value is 1.
9 . The terminal of claim 7 , wherein the at least one processor is further configured to set a value of a Last_Submitted_PDCP_RX_SN variable, which indicates an SN of PDCP data most recently transferred to an upper layer, as a value obtained by subtracting a second setting value from a value of the SN of the first PDCP data.
10 . The terminal of claim 9 , wherein the at least one processor is further configured to start a PDCP reordering timer, based on the value of the Next_PDCP_RX_SN variable and the value of the Last_Submitted_PDCP_RX_SN variable.
11 . The terminal of claim 10 , wherein the at least one processor is further configured to set a value of a Reordering_PDCP_RX_COUNT variable by using the value of the Next_PDCP_RX_SN variable, the Reordering_PDCP_RX_COUNT variable being used by the PDCP reordering timer.
12 . The terminal of claim 7 , wherein the PDCP data is transmitted from the transmission entity by using a vehicle-to-everything (V2X) communication scheme.