Packet transmission method performed by node in wireless communication system and terminal using said method
The present invention provides a method for forwarding an uplink packet performed by a node in a wireless communication system, the method being characterized in that the uplink packet including a first cost is received, the first cost is compared with a second cost corresponding to a cost of the node to determine whether to forward the uplink packet, and on the basis of the determination the uplink packet is forwarded, the node forwards the uplink packet when a value of the second cost is smaller than a value of the first cost, and the node does not forward the uplink packet when the second cost value is not smaller than the first cost value.
1. A method for forwarding an uplink packet, in a wireless communication system, the method performed by a first user equipment (UE) which supports a vehicle-to-X (V2X) and comprising:
receiving, from a second UE, the uplink packet including a first cost;
determining whether to forward the uplink packet by comparing the first cost with a second cost corresponding to a cost of the first UE; and
forwarding, to a third UE, the uplink packet based on the determination,
wherein if a value of the second cost is smaller than a value of the first cost, the first UE forwards the uplink packet, and
if the value of the second cost is not smaller than the value of the first cost, the first UE does not forward the uplink packet,
wherein the second cost is determined based on a subcarrier index value of a first tone signal transmitted from the second UE and a signal-to-noise ratio of the first tone signal,
wherein the value of the second cost when the signal-to-noise ratio of the first tone signal is greater than a preset threshold value is greater than the value of the second cost when the signal-to-noise ratio of the first tone signal is not greater than the preset threshold value,
wherein the value of the second cost when the signal-to-noise ratio of the first tone signal is greater than the preset threshold value is determined by an equation:
C A =( i −1)× SNR THRES +1,
wherein C A is a value of the determined second cost, i is the subcarrier index value, and SNR THRES is the preset threshold value,
wherein the value of the second cost when the signal-to-noise ratio of the first tone signal is not greater than the preset threshold value is determined by an equation:
C A =( i− 1)× SNR THRES +┌ SNR THRES +1− SNR TONE ┐,
wherein C A is a value of the determined second cost, i is the subcarrier index value, SNR THRES is the preset threshold value, and SNR TONE is the signal-to-noise ratio of the first tone signal,
wherein the uplink packet further includes information on a maximum number of nodes through which the uplink packet may be forwarded,
wherein when the first UE transmits a second tone signal to the third UE, the first UE transmits the second tone signal on a subcarrier having a subcarrier index value (i+1), when the value of the second cost is smaller than the value of the first cost, and
wherein the first UE transmits the second tone signal to the third UE during a short inter-frame space.
2. A first user equipment (UE), which supports a vehicle-to-X (V2X), comprising:
a transceiver configured to transmit and receive a wireless signal; and
a processor coupled with the transceiver,
wherein the processor is configured to:
control the transceiver to receive, from a second UE, an uplink packet including a first cost;
determine whether to forward the uplink packet by comparing the first cost with a second cost corresponding to a cost of the first UE; and
control the transceiver to forward, to a third UE, the uplink packet based on the determination,
wherein if a value of the second cost is smaller than a value of the first cost, the first UE forwards the uplink packet, and
if the value of the second cost is not smaller than the value of the first cost, the first UE does not forward the uplink packet,
wherein the second cost is determined based on a subcarrier index value of a first tone signal transmitted from the second UE and a signal-to-noise ratio of the first tone signal,
wherein the value of the second cost when the signal-to-noise ratio of the first tone signal is greater than a preset threshold value is greater than the value of the second cost when the signal-to-noise ratio of the first tone signal is not greater than the preset threshold value,
wherein the value of the second cost when the signal-to-noise ratio of the first tone signal is greater than the preset threshold value is determined by an equation:
C A =( i −1)× SNR THRES +1,
wherein C A is a value of the determined second cost, i is the subcarrier index value, and SNR THRES is the preset threshold value,
wherein the value of the second cost when the signal-to-noise ratio of the first tone signal is not greater than the preset threshold value is determined by an equation:
C A =( i− 1)× SNR THRES +┌ SNR THRES +1− SNR TONE ┐,
wherein C A is a value of the determined second cost, i is the subcarrier index value, SNR THRES is the preset threshold value, and SNR TONE is the signal-to-noise ratio of the first tone signal,
wherein the uplink packet further includes information on a maximum number of nodes through which the uplink packet may be forwarded,
wherein when the first UE transmits a second tone signal to the third UE, the first UE transmits the second tone signal on a subcarrier having a subcarrier index value (i+1), when the value of the second cost is smaller than the value of the first cost, and
wherein the first UE transmits the second tone signal to the third UE during a short inter-frame space.