Method by which multi-RU receives LDPC-tone-mapped PPDU in wireless LAN system, and apparatus

1. A method in a wireless LAN system, the method comprising:

receiving a Physical Protocol Data Unit (PPDU) including a data field by a receiving station (STA) from a transmitting STA; and

decoding the data field by the receiving STA,

wherein the data field is received through a Multiple-Resource Unit (Multi-RU),

Low Density Parity Check (LDPC) tone mapping is performed on a data tone included in the data field based on a first parameter for the Multi-RU, and

when the Multi-RU is an RU in which a 242 tone RU and a 484 tone RU are aggregated, the first parameter is 18.

2. The method of claim 1 , wherein, when the Multi-RU is an RU in which a 26 tone RU and a 52 tone RU are aggregated, the first parameter is 4, and

when the Multi-RU is an RU in which a 26 tone RU and a 106 tone RU are aggregated, the first parameter is 6.

3. The method of claim 2 , wherein the data field is generated based on a bitstream,

the bitstream is mapped to the data tone based on constellation mapping, and

tone spacing of the data tone is set to the first parameter for the Multi-RU based on the LDPC tone mapping.

4. The method of claim 3 , wherein the index of the data tone is determined as t(k)=D TM (k mod N SD /D TM )+floor(k*D TM /N DS ),

where t(k) is the index of the data tone,

D TM is the first parameter,

k is the index of a tone to which the bitstream has been mapped,

N SD is the number of data tones in the Multi-RU, and

floor is a rounding-down function.

5. The method of claim 4 , wherein, when Dual Carrier Modulation (DCM) is performed on the bitstream,

the bitstream is mapped to a first data tone based on first constellation mapping and mapped to a second data tone based on second constellation mapping,

tone spacing for each of the first and second data tones is set to the second parameter for the Multi-RU based on the LDPC tone mapping,

the first and second data tones are included in the data tone, and

when the Multi-RU is an RU in which a 242 tone RU and a 484 tone RU are aggregated, the second parameter is 13.

6. The method of claim 5 , wherein the first data tone is a lower half tone on the frequency domain, and

the second data tone is an upper half tone on the frequency domain.

7. The method of claim 6 , wherein the index of the first data tone is determined as t(k)=D TM_DCM (k mod N SD /D TM_DCM )+floor(k=D TM_DCM /N SD ),

where t(k) is the index of the first data tone,

D TM DCM is the second parameter,

k is the index of a tone to which the bitstream has been mapped,

N SD is the number of data tones in the Multi-RU, and

floor is a rounding-down function.

8. The method of claim 6 , wherein the index of the second data tone is determined as

t ( k )= D TM_DCM (( k−N SD ) mod N SD /D TM_DCM )+floor(( k−N SD )* D TM DCM /N SD )+ N SD ,

where t(k) is the index of the second data tone,

D TM DCM the second parameter,

k is the index of a tone to which the bitstream has been mapped,

N SD is the number of data tones in the Multi-RU, and

floor is a rounding-down function.

9. The method of claim 2 , wherein the 26 tone RU is a resource unit composed of 26 tones,

the 52 tone RU is a resource unit composed of 52 tones, and

the 26 tone RU and the 52 tone RU are adjacent to each other or included within a 20 MHz channel.

10. The method of claim 2 , wherein the 26 tone RU is a resource unit composed of 26 tones,

the 106 tone RU is a resource unit composed of 106 tones, and

the 26 tone RU and the 106 tone RU are adjacent to each other or included within a 20 MHz channel.

11. The method of claim 1 , wherein the PPDU further includes a control field, and

the control field includes allocation information on the Multi-RU.

12. A receiving station (STA) in a wireless LAN system, the receiving STA comprising:

a memory;

a transceiver; and

a processor combined operatively with the memory and the transceiver, wherein the processor is configured to:

receive a Physical Protocol Data Unit (PPDU) including a data field from a transmitting STA; and

decode the data field,

wherein the data field is received through a Multiple-Resource Unit (Multi-RU),

Low Density Parity Check (LDPC) tone mapping is performed on a data tone included in the data field based on a first parameter for the Multi-RU, and

when the Multi-RU is an RU in which a 242 tone RU and a 484 tone RU are aggregated, the first parameter is 18.

13. A method in a wireless LAN system, the method comprising:

generating a Physical Protocol Data Unit (PPDU) including a data field by a transmitting station (STA); and

transmitting the PPDU to a receiving STA by the transmitting STA, wherein the data field is transmitted through a Multiple-Resource Unit (Multi-RU),

Low Density Parity Check (LDPC) tone mapping is performed on a data tone included in the data field based on a first parameter for the Multi-RU, and

when the Multi-RU is an RU in which a 242 tone RU and a 484 tone RU are aggregated, the first parameter is 18.

14. The method of claim 13 , wherein, when the Multi-RU is an RU in which a 26 tone RU and a 52 tone RU are aggregated, the first parameter is 4, and

when the Multi-RU is an RU in which a 26 tone RU and a 106 tone RU are aggregated, the first parameter is 6.

15. The method of claim 14 , wherein the data field is generated based on a bitstream,

the bitstream is mapped to the data tone based on constellation mapping, and

tone spacing of the data tone is set to the first parameter for the Multi-RU based on the LDPC tone mapping.