Method and device for determining TBS in NR V2X
Provided are a method for performing sidelink transmission by a first device ( 100 ) in a wireless communication system, and a device for supporting same. The method comprises the steps of: determining a transport block size (TBS) on the basis of whether at least one of an automatic gain control (AGC) symbol and a guard period (GP) symbol is used for sidelink transmission; and performing the sidelink transmission with respect to a second device ( 200 ) on the basis of the determined TBS, wherein the AGC symbol may be a symbol which a first device ( 100 ) uses for AGC, and the GP symbol may be a symbol which the first device ( 100 ) uses for TX/RX switching.
1. A method for performing, by a first apparatus, wireless communication, the method comprising:
determining a number of resource elements (REs) allocated for a physical sidelink shared channel (PSSCH) within one slot and one physical resource block (PRB);
determining a transport block size (TBS) based on the number of REs; and
based on the TBS, performing sidelink (SL) transmission to a second apparatus,
wherein the number of REs is determined based on a value obtained by subtracting an overhead value from a value obtained by multiplying 2 subtracted from a number of SL symbols within the one slot with a number of subcarriers within the one PRB.
2. The method of claim 1 , wherein the overhead value includes an overhead value configured by an upper layer parameter and a number of REs related to demodulation reference signal (DMRS).
3. The method of claim 1 , wherein the number of subcarriers within the one PRB is 12.
4. The method of claim 1 , wherein information related to the number of SL symbols within the one slot is received from a base station.
5. The method of claim 1 , wherein the number of REs (N′ RE ) is obtained based on the following equation,
N′ RE =N RB sc ·( N sh symb −2)− N DMRS −N Oh
wherein the N RB sc is 12, the N sh symb is the number of SL symbols within the one slot, the N DMRS is a number of REs related to demodulation reference signal (DMRS), and the N Oh is an overhead configured by a higher layer parameter.
6. The method of claim 5 , wherein the Ns h symb − 2 is a value obtained by subtracting a number of symbols related to automatic gain control (AGC) and a number of symbols related to guard period (GP) from the number of SL symbols within the one slot.
7. The method of claim 6 , wherein the symbol related to the GP is a last symbol among the SL symbols within the one slot.
8. The method of claim 6 , wherein the symbol related to the AGC is a first symbol among the SL symbols within the one slot.
9. The method of claim 1 , wherein determining the TBS based on the number of REs includes: (i) obtaining an intermediate number related to the TBS by multiplying the number of REs, code rate, modulation order, and a number of layers, (ii) quantizing the intermediate number, and (iii) determining the TBS based on the quantized intermediate number.
10. A first apparatus for performing wireless communication, the first apparatus 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:
determine a number of resource elements (REs) allocated for a physical sidelink shared channel (PSSCH) within one slot and one physical resource block (PRB);
determine a transport block size (TBS) based on the number of REs; and
based on the TBS, perform sidelink (SL) transmission to a second apparatus,
wherein the number of REs is determined based on a value obtained by subtracting an overhead value from a value obtained by multiplying 2 subtracted from a number of SL symbols within the one slot with a number of subcarriers within the one PRB.
11. The first apparatus of claim 10 , wherein the overhead value includes an overhead value configured by an upper layer parameter and a number of REs related to demodulation reference signal (DMRS).
12. The first apparatus of claim 10 , wherein the number of subcarriers within the one PRB is 12.
13. The first apparatus of claim 10 , wherein information related to the number of SL symbols within the one slot is received from a base station.
14. The first apparatus of claim 10 , wherein the number of REs (N′ RE ) is obtained based on the following equation,
N′ RE =N RB sc −( N sh symb −2)− N DMRS −N Oh
wherein the N RB sc is 12, the N sh symb is the number of SL symbols within the one slot, the N DMRS is a number of REs related to demodulation reference signal (DMRS), and the N Oh is an overhead configured by a higher layer parameter.
15. An apparatus configured to control a first user equipment (UE), the apparatus 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:
determine a number of resource elements (REs) allocated for a physical sidelink shared channel (PSSCH) within one slot and one physical resource block (PRB);
determine a transport block size (TBS) based on the number of REs; and
based on the TBS, perform sidelink (SL) transmission to a second UE,
wherein the number of REs is determined based on a value obtained by subtracting an overhead value from a value obtained by multiplying 2 subtracted from a number of SL symbols within the one slot with a number of subcarriers within the one PRB.
16. The apparatus of claim 15 , wherein the overhead value includes an overhead value configured by an upper layer parameter and a number of REs value related to demodulation reference signal (DMRS).
17. The apparatus of claim 15 , wherein the number of subcarriers within the one PRB is 12.
18. The apparatus of claim 15 , wherein information related to the number of SL symbols within the one slot is received from a base station.
19. The apparatus of claim 15 , wherein the number of REs (N′ RE ) is obtained based on the following equation,
N′ RE =N RB sc ·( N sh symb −2)− N DMRS −N Oh
wherein the N RB sc is 12, the N sh symb is the number of SL symbols within the one slot, the N DMRS is a number of REs related to demodulation reference signal (DMRS), and the Non is an overhead configured by a higher layer parameter.
20. The apparatus of claim 19 , wherein the N sh symb −2 is a value obtained by subtracting a number of symbols related to automatic gain control (AGC) and a number of symbols related to guard period (GP) from the number of SL symbols within the one slot.