Method and apparatus for generating training signal using predetermined binary sequence in wireless LAN system
Disclosed are a method and an apparatus for generating an STF signal usable in a wireless LAN system. The STF signal is included in a field used to improve AGC estimation of a MIMO transmission. A portion of the STF signal is used to transmit an uplink, and can be used for uplink MU PPDUs transmitted from a plurality of STAs. The STF signal that is disclosed, for example, is used for a 40 MHz band or an 80 MHz band, is desirably usable for the 40 MHz band, and can be generated based on a sequence in which a predetermined M sequence is repeated. The predetermined M sequence can be a binary sequence of which the length is 15 bits.
1. A method performed by a transmitting apparatus in a wireless local area network (LAN) system, the method comprising:
generating a short training field (STF) signal for a frequency band, wherein the STF signal is generated based on an STF sequence which includes an M sequence; and
transmitting the generated STF signal on the frequency band to a receiving apparatus,
wherein the M sequence has 15 elements and is defined as M={−1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1}, and
wherein the STF sequence is a frequency-domain sequence in which elements are positioned at frequencies spaced apart by a frequency tone interval, and wherein:
(i) for the frequency band corresponding to 80 MHz and for the frequency tone interval equal to 16 tones: the STF sequence is defined as {M, 1, −M, 0, −M, 1, −M}*(1+j)/sqrt(2),
(ii) for the frequency band corresponding to 80 MHz and for the frequency tone interval equal to 8 tones: the STF sequence is defined as {M, −1, M, −1, −M, −1, M, 0, −M, 1, M, 1, −M, 1, −M}*(1+j)/sqrt(2), and
(iii) for the frequency band corresponding to 40 MHz and for the frequency tone interval equal to 8 tones: the STF sequence is defined as {M, −1, −M, 0, M, −1, M}*(1+j)/sqrt(2),
wherein sqrt( ) denotes a square root.
2. The method of claim 1 , wherein:
(i) for the frequency band corresponding to 80 MHz and for the frequency tone interval equal to 16 tones: the elements of the STF sequence are positioned at intervals of 16 tones starting from a lowest tone having a tone index of −496 to a highest tone having a tone index of +496, and wherein elements for the −496 tone index and the +496 tone index are processed as null elements,
(ii) for the frequency band corresponding to 80 MHz and for the frequency tone interval equal to 8 tones: the elements of the STF sequence are positioned at intervals of 8 tones starting from a lowest tone having a tone index of 504 to a highest tone having a tone index of +504, and wherein elements for the 504 tone index and the +504 tone index are processed as null elements, and
(iii) for the frequency band corresponding to 40 MHz and for the frequency tone interval equal to 8 tones: the elements of the STF sequence are positioned at intervals of 8 tones starting from a lowest tone having a tone index of −248 to a highest tone having a tone index of +248, and wherein elements for the −248 tone index and the +248 tone index are processed as null elements.
3. The method of claim 1 , further comprising:
selecting a first frequency tone interval of 8 or a second frequency tone interval of 16 as a frequency spacing for the STF sequence,
wherein the STF signal is generated based on the selected first frequency tone interval or second frequency tone interval as the frequency spacing for the STF sequence.
4. The method of claim 1 , wherein elements in the STF sequence are defined in units of 78.125 kHz.
5. The method of claim 1 , wherein the STF sequence is defined so as to reduce a Peak-to-Average Power Ratio (PAPR) of the transmission of the STF signal.
6. The method of claim 1 , further comprising using the transmission of the STF signal for uplink Orthogonal Frequency Division Multiple Access (OFDMA) transmission.
7. The method of claim 1 , wherein the transmission of the STF signal includes at least one resource unit (RU), the at least one RU including at least 26, 52, 106, or 242 tones.
8. The method of claim 1 , wherein:
(i) for the frequency band corresponding to 80 MHz and for the frequency tone interval equal to 16 tones: the STF sequence is equal to {−1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1, 1, 1, 1, 1, −1, −1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1, 0, 1, 1, 1, −1, −1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1, 1, 1, 1, 1, −1, −1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1}*(1+j)/sqrt(2),
(ii) for the frequency band corresponding to 80 MHz and for the frequency tone interval equal to 8 tones: the STF sequence is equal to {−1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1, −1, −1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1, −1, 1, 1, 1, −1, −1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1, −1, −1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1, 0, 1, 1, 1, −1, −1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1, 1, −1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1, 1, 1, 1, 1, −1, −1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1, 1, 1, 1, 1, −1, −1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1}*(1+j)/sqrt(2), and
(iii) for the frequency band corresponding to 40 MHz and for the frequency tone interval equal to 8 tones: the STF sequence is equal to {−1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1, −1, 1, 1, 1, −1, −1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1, 0, −1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1, −1, −1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1}*(1+j)/sqrt(2).
9. The method of claim 1 , wherein the STF signal is generated based on the STF sequence by mapping elements of the STF sequence to coefficients of a plurality of subcarriers, wherein the plurality of subcarriers are arranged at frequency positions that are spaced apart by the frequency tone interval.
10. The method of claim 1 , wherein transmitting the STF signal comprises transmitting a physical-layer protocol data unit (PPDU) that includes the STF signal.
11. A transmitting apparatus configured to operate in a wireless local area network (LAN) system, the transmitting apparatus comprising:
at least one transceiver;
at least one processor; and
at least one computer memory operably connectable to the at least one processor and storing instructions that, based on being executed by the at least one processor, perform operations comprising:
generating a short training field (STF) signal for a frequency band, wherein the STF signal is generated based on an STF sequence which includes an M sequence; and
transmitting the generated STF signal on the frequency band to a receiving apparatus through the at least one transceiver,
wherein the M sequence has 15 elements and is defined as M={−1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1}, and
wherein the STF sequence is a frequency-domain sequence in which elements are positioned at frequencies spaced apart by a frequency tone interval, and wherein:
(i) for the frequency band corresponding to 80 MHz and for the frequency tone interval equal to 16 tones: the STF sequence is defined as {M, 1, −M, 0, −M, 1, −M}*(1+j)/sqrt(2),
(ii) for the frequency band corresponding to 80 MHz and for the frequency tone interval equal to 8 tones: the STF sequence is defined as {M, −1, M, −1, −M, −1, M, 0, −M, 1, M, 1, −M, 1, −M}*(1+j)/sqrt(2), and
(iii) for the frequency band corresponding to 40 MHz and for the frequency tone interval equal to 8 tones: the STF sequence is defined as {M, −1, −M, 0, M, −1, M}*(1+j)/sqrt(2),
wherein sqrt( ) denotes a square root.
12. The transmitting apparatus of claim 11 , wherein:
(i) for the frequency band corresponding to 80 MHz and for the frequency tone interval equal to 16 tones: the elements of the STF sequence are positioned at intervals of 16 tones starting from a lowest tone having a tone index of −496 to a highest tone having a tone index of +496, and wherein elements for the −496 tone index and the +496 tone index are processed as null elements,
(ii) for the frequency band corresponding to 80 MHz and for the frequency tone interval equal to 8 tones: the elements of the STF sequence are positioned at intervals of 8 tones starting from a lowest tone having a tone index of −504 to a highest tone having a tone index of +504, and wherein elements for the −504 tone index and the +504 tone index are processed as null elements, and
(iii) for the frequency band corresponding to 40 MHz and for the frequency tone interval equal to 8 tones: the elements of the STF sequence are positioned at intervals of 8 tones starting from a lowest tone having a tone index of −248 to a highest tone having a tone index of +248, and wherein elements for the −248 tone index and the +248 tone index are processed as null elements.
13. The transmitting apparatus of claim 11 , wherein the operations further comprise:
selecting a first frequency tone interval of 8 or a second frequency tone interval of 16 as a frequency spacing for the STF sequence,
wherein the STF signal is generated based on the selected first frequency tone interval or second frequency tone interval as the frequency spacing for the STF sequence.
14. The transmitting apparatus of claim 11 , wherein elements in the STF sequence are defined in units of 78.125 kHz.
15. The transmitting apparatus of claim 11 , wherein the STF sequence is defined so as to reduce a Peak-to-Average Power Ratio (PAPR) of the transmission of the STF signal.
16. The transmitting apparatus of claim 11 , wherein the operations further comprise:
using the transmission of the STF signal for uplink Orthogonal Frequency Division Multiple Access (OFDMA) transmission.
17. The transmitting apparatus of claim 11 , wherein the transmission of the STF signal includes at least one resource unit (RU), the at least one RU including at least 26, 52, 106, or 242 tones.
18. The transmitting apparatus of claim 11 , wherein:
(i) for the frequency band corresponding to 80 MHz and for the frequency tone interval equal to 16 tones: the STF sequence is equal to {−1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1, 1, 1, 1, 1, −1, −1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1, 0, 1, 1, 1, −1, −1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1, 1, 1, 1, 1, −1, −1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1}*(1+j)/sqrt(2),
(ii) for the frequency band corresponding to 80 MHz and for the frequency tone interval equal to 8 tones: the STF sequence is equal to {−1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1, −1, −1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1, −1, 1, 1, 1, −1, −1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1, −1, −1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1, 0, 1, 1, 1, −1, −1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1, 1, −1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1, 1, 1, 1, 1, −1, −1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1, 1, 1, 1, 1, −1, −1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1}*(1+j)/sqrt(2), and
(iii) for the frequency band corresponding to 40 MHz and for the frequency tone interval equal to 8 tones: the STF sequence is equal to {−1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1, −1, 1, 1, 1, −1, −1, −1, 1, −1, −1, −1, 1, −1, −1, 1, −1, 0, −1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1, −1, −1, −1, −1, 1, 1, 1, −1, 1, 1, 1, −1, 1, 1, −1, 1}*(1+j)/sqrt(2).
19. The transmitting apparatus of claim 11 , wherein the STF signal is generated based on the STF sequence by mapping elements of the STF sequence to coefficients of a plurality of subcarriers, wherein the plurality of subcarriers are arranged at frequency positions that are spaced apart by the frequency tone interval.
20. The transmitting apparatus of claim 11 , wherein transmitting the STF signal comprises transmitting a physical-layer protocol data unit (PPDU) that includes the STF signal.