Patent ID: 8494089

Claim:
A wireless communication device for communicating with a second wireless communication device by using a first wireless packet, the wireless communication device comprising: a first signal generator configured to generate a signal for transmitting the first wireless packet, the first wireless packet including: a short-preamble used for a first automatic gain control (1st AGC) at the second wireless communication device, a first long-preamble used for a first estimation of a first channel response between the wireless communication device and the second wireless communication device, a signal field following the short-preamble and the first long-preamble, and used for conveying information regarding the first wireless packet, an AGC preamble following the signal field, and used for a second automatic gain control (2nd AGC) performed after the first automatic gain control at the second wireless communication device, a second long-preamble used for a second estimation of a second channel response between the wireless communication device and the second wireless communication device, and a data field conveying data, wherein the AGC preamble is to be transmitted via at least a first antenna and a second antenna, a signal of the AGC preamble to be transmitted via the first antenna is to be transmitted via first subcarriers, a signal of the AGC preamble to be transmitted via the second antenna is to be transmitted via second subcarriers, the first subcarriers and the second subcarriers are same, and the signal of the AGC preamble to be transmitted via the first antenna is substantially same as a signal obtained by performing a cyclic shift in time domain on the signal of the AGC preamble to be transmitted via the second antenna.