Method and device for performing congestion control in NR V2X
A method for performing wireless communication by a first apparatus and an apparatus for supporting same are provided. The method may comprise: measuring, in a first slot, a channel busy ratio (CBR) for a resource pool; determining power for physical sidelink shared channel (PSSCH) transmission in a second slot, based on the CBR measured in the first slot; and performing, to a second device, the PSSCH transmission in the second slot based on the power, wherein the first slot is a slot before N slots from the second slot, wherein the N is determined based on subcarrier spacing (SCS) related to the PSSCH transmission, and wherein the N is a positive integer.
1. A method by a first device, the method comprising:
measuring, in a first slot, a channel busy ratio (CBR), which is a portion of sub-channels, in a resource pool whose received signal strength indicator, RSSI, exceeds a threshold RSSI;
determining power for physical sidelink shared channel (PSSCH) transmission in a second slot, based on the CBR measured in the first slot; and
performing, to a second device, the PSSCH transmission in the second slot based on the power,
wherein the first slot is a slot before congestion control processing time from the second slot,
wherein a number of slots regarding the congestion control processing time is based on subcarrier spacing (SCS) of sidelink channel with which the PSSCH is to be transmitted.
2. The method of claim 1 , wherein the larger the SCS related to the PSSCH transmission, the larger the number of slots is.
3. The method of claim 2 , wherein the SCS is one of 15 kHz, 30 kHz, 60 kHz or 120 kHz.
4. The method of claim 1 , wherein an index of the first slot is a value obtained by subtracting the number of slots from an index of the second slot.
5. The method of claim 1 , wherein the RSSI is measured for the resource pool for a time interval including a plurality of slots before the first slot.
6. The method of claim 5 , wherein the RSSI is measured for the resource pool for the time interval from (i) a third slot before 100 slots from the first slot to (ii) a fourth slot before 1 slot from the first slot.
7. The method of claim 5 , wherein the RSSI is measured for the resource pool for the time interval from (i) 100 ms before the first slot to (ii) 1 ms before the first slot.
8. The method of claim 1 , wherein maximum transmit power related to the PSSCH transmission is configured for the first device for each range of the CBR.
9. The method of claim 1 , wherein a size of a precoding resource block group (PRG) related to the PSSCH transmission is configured for the first device.
10. The method of claim 9 , wherein the size of the PRG is applied based on a resource block (RB) regardless of a sub-channel.
11. The method of claim 10 , wherein a same precoding is applied to consecutively allocated RBs included in the PRG.
12. The method of claim 1 , further comprising:
transmitting, to the second device, information related to a sensing type of the first device,
wherein the sensing type includes partial sensing or full sensing.
13. The method of claim 1 , further comprising:
transmitting, to the second device, information related to a resource allocation mode of the first device.
14. A first device comprising:
one or more processors;
one or more transceivers; and
one or more memories connected to the one or more processors and the one or more transceivers and storing instructions to perform operations comprising:
measuring, in a first slot, a channel busy ratio (CBR), which is a portion of sub-channels, in a resource pool whose received signal strength indicator, RSSI, exceeds a threshold RSSI;
determining power for physical sidelink shared channel (PSSCH) transmission in a second slot, based on the CBR measured in the first slot; and
performing, to a second device, the PSSCH transmission in the second slot based on the power,
wherein the first slot is a slot before congestion control processing time from the second slot,
wherein a number of slots regarding the congestion control processing time is based on subcarrier spacing (SCS) of sidelink channel with which the PSSCH is to be transmitted.
15. The first device of claim 14 , wherein the larger the SCS related to the PSSCH transmission, the larger the number of slots is.
16. The first device of claim 15 , wherein the SCS is one of 15 kHz, 30 kHz, 60 kHz or 120 kHz.
17. The first device of claim 14 , wherein an index of the first slot is a value obtained by subtracting the number of slots from an index of the second slot.
18. The first device of claim 14 , wherein the RSSI is measured for the resource pool for a time interval including a plurality of slots before the first slot.
19. The first device of claim 18 , wherein the RSSI is measured for the resource pool for the time interval from (i) a third slot before 100 slots from the first slot to (ii) a fourth slot before 1 slot from the first slot.
20. A processing apparatus adapted to control a first device, the apparatus comprising:
one or more processors; and
one or more memories operably connected to the one or more processors and storing instructions to perform operations comprising:
measuring, in a first slot, a channel busy ratio (CBR), which is a portion of sub-channels, in a resource pool whose received signal strength indicator, RSSI, exceeds a threshold RSSI;
determining power for physical sidelink shared channel (PSSCH) transmission in a second slot, based on the CBR measured in the first slot; and
performing, to a second device, the PSSCH transmission in the second slot based on the power,
wherein the first slot is a slot before congestion control processing time from the second slot,
wherein a number of slots regarding the congestion control processing time is based on subcarrier spacing (SCS) of sidelink channel with which the PSSCH is to be transmitted.