Method and device for determining sidelink transmit power in NR V2X
Provided are a method by which a first device performs wireless communication, and a device for supporting same. The method can comprise the steps of: transmitting one or more reference signals (RSs) to a second device on the basis of first transmit power; receiving, from the second device, information related to a channel state measured on the basis of the one or more RSs; changing the first transmit power to second transmit power on the basis of the information related to the channel state; and transmitting the one or more RSs to the second device on the basis of the second transmit power.
1. A method for performing wireless communication by a first device, the method comprising:
transmitting, to a second device, sidelink control information (SCI);
transmitting, to the second device, a demodulation reference signal (DMRS);
obtaining reference signal power from transmit power layer-3 (L3) filtered using L3 filter coefficient information;
receiving, from the second device, a reference signal received power (RSRP) obtained from the DMRS;
obtaining a sidelink (SL) pathloss by subtracting the RSRP from the reference signal power;
determining power for a physical sidelink shared channel (PSSCH) transmission based on the SL pathloss; and
performing the PSSCH transmission based on the power.
2. The method of claim 1 , wherein the L3 is a radio resource control (RRC) layer.
3. The method of claim 1 , wherein the RSRP is obtained from the DMRS using the L3 filter coefficient information.
4. The method of claim 3 , wherein the L3 filter coefficient information used for the transmit power L3 filtering and the RSRP L3 filtering correspond to a same filter coefficient value.
5. The method of claim 1 , wherein the L3 filter coefficient information is configured for each resource pool.
6. The method of claim 1 , further comprising:
establishing a unicast connection with the second device.
7. The method of claim 6 , wherein, based on the establishment of the unicast connection between the first device and the second device, the power for the PSSCH transmission is determined based on the SL pathloss.
8. The method of claim 1 , further comprising:
obtaining a downlink (DL) pathloss between the first device and a base station,
wherein the power for the PSSCH transmission is determined based on a minimum value among (i) first transmit power obtained based on the SL pathloss and (ii) second transmit power obtained based on the DL pathloss.
9. The method of claim 1 , wherein the DMRS is transmitted to the second device based on a resource allocated for a PSSCH.
10. The method of claim 1 , wherein the transmit power is time-varying.
11. A first device adapted to perform wireless communication, the first device comprising:
one or more memories storing instructions;
one or more transceivers; and
one or more processors connected to the one or more memories and the one or more transceivers, wherein the one or more processors execute the instructions to:
transmit, to a second device, sidelink control information (SCI);
transmit, to the second device, a demodulation reference signal (DMRS);
obtain reference signal power from transmit power layer-3 (L3) filtered using L3 filter coefficient information;
receive, from the second device, a reference signal received power (RSRP) obtained from the DMRS;
obtain a sidelink (SL) pathloss by subtracting the RSRP from the reference signal power;
determine power for a physical sidelink shared channel (PSSCH) transmission based on the SL pathloss; and
perform the PSSCH transmission based on the power.
12. The first device of claim 11 , wherein the L3 is a radio resource control (RRC) layer.
13. The first device of claim 11 , wherein the RSRP is obtained from the DMRS using the L3 filter coefficient information.
14. The first device of claim 13 , wherein the L3 filter coefficient information used for the transmit power L3 filtering and the RSRP L3 filtering correspond to a same filter coefficient value.
15. The first device of claim 11 , wherein the L3 filter coefficient information is configured for each resource pool.
16. A processing device adapted to control a first device, the processing device comprising:
one or more processors; and
one or more memories operably connected to the one or more processors and storing instructions, wherein the one or more processors execute the instructions to:
transmit, to a second device, sidelink control information (SCI);
transmit, to the second device, a demodulation reference signal (DMRS);
obtain reference signal power from transmit power layer-3 (L3) filtered using L3 filter coefficient information;
receive, from the second device, a reference signal received power (RSRP) obtained from the DMRS;
obtain a sidelink (SL) pathloss by subtracting the RSRP from the reference signal power;
determine power for a physical sidelink shared channel (PSSCH) transmission based on the SL pathloss; and
perform the PSSCH transmission based on the power.
17. The processing device of claim 16 , wherein the L3 is a radio resource control (RRC) layer.
18. The processing device of claim 16 , wherein the RSRP is obtained from the DMRS using the L3 filter coefficient information.
19. The processing device of claim 18 , wherein the L3 filter coefficient information used for the transmit power L3 filtering and the RSRP L3 filtering correspond to a same filter coefficient value.
20. The processing device of claim 16 , wherein the L3 filter coefficient information is configured for each resource pool.