Method and apparatus for generating training signal using predetermined binary sequence in wireless LAN system
A method and an apparatus for generating an STF signal usable in a wireless LAN system is provided. 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 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 15 bits.
1. A method in a wireless local area network (LAN) system, the method performed by a transmitting apparatus and comprising:
generating a short training field (STF) signal for a frequency band based on an STF sequence, the STF sequence including an M sequence; and
transmitting the 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},
wherein the STF sequence is defined as {M, −1, −M, 0, M, −1, M}*(1+j)/sqrt(2), and
wherein sqrt( ) denotes a square root and “*” denotes a multiplication sign.
2. The method of claim 1 , wherein:
the STF sequence is 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
elements for to the −248 and 284 tone indexes are processed as null elements.
3. The method of claim 1 , further comprising selecting a first frequency tone interval or a second frequency tone interval, wherein the STF signal is generated based on the selected first frequency tone interval or second frequency tone interval.
4. The method of claim 3 , wherein the first frequency tone interval is 8 and the second frequency tone interval is 16.
5. The method of claim 1 , wherein elements in the STF sequence are defined in units of 78.125 kHz.
6. The method of claim 1 , wherein the STF signal is transmitted based on an uplink Orthogonal Frequency Division Multiple Access (OFDMA) scheme.
7. The method of claim 1 , wherein the transmitted packet 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 the frequency band is a 40 MHz band.
9. A transmitting apparatus of a wireless local area network (LAN) system, the apparatus comprising:
a transceiver configured to transmit and receive radio signals; and
a processor configured to:
generate a short training field (STF) signal for a frequency band based on an STF sequence, the STF sequence including an M sequence; and
control the transceiver to transmit the 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},
wherein the STF sequence is defined as {M, −1, −M, 0, M, −1, M}*(1+j)/sqrt(2), and
wherein sqrt( ) denotes a square root and “*” denotes a multiplication sign.
10. The apparatus of claim 9 , wherein:
the STF sequence is 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
elements for to the −248 and 284 tone indexes are processed as null elements.
11. The apparatus of claim 9 , wherein the processor is further configured to select a first frequency tone interval or a second frequency tone interval, wherein the STF signal is generated based on the selected first frequency tone interval or second frequency tone interval.
12. The apparatus of claim 11 , wherein the first frequency tone interval is 8 and the second frequency tone interval is 16.
13. The apparatus of claim 9 , wherein elements in the STF sequence are defined in units of 78.125 kHz.
14. The apparatus of claim 9 , wherein the STF signal is transmitted based on an uplink Orthogonal Frequency Division Multiple Access (OFDMA) scheme.
15. The apparatus of claim 9 , wherein the transmitted packet includes at least one resource unit (RU), the at least one RU including at least 26, 52, 106 or 242 tones.
16. The apparatus of claim 9 , wherein the frequency band is a 40 MHz band.