| 摘要 |
The disclosed invention determines whether a reception packet is an MM (Mixed Mode) packet or a GF (Green-Field) packet with precision and avoids unnecessary decoding operations performed at the GF-packet-reception time and inefficient communications. An OFDM symbol including 52 tones is transmitted when the MM packet is used, but an OFDM symbol including 56 tones is transmitted when the GF packet is used. Therefore, it is verified whether or not a signal exists in an FFT output at each of ±27 and 28 shown in a subcarrier index so that the format of the reception packet is determined. Otherwise, the packet format is determined on the basis of the Cyclic-Shift amount that changes for every format. When the GF packet is used, decoding processing performed in an L-SIG and afterward is stopped. |
