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 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 (103, 104) following the short-preamble and the first long-preamble, and used for conveying information regarding the first wireless packet, an AGC preamble (105A to 105D) following the signal field, and used for a second automatic gain control performed after the first automatic gain control at the second wireless communication device, a second long-preamble (106A to 106D, 107A to 107D, 108A to 108D, 109A to 109D) 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 (110A to 110D) conveying data, wherein the AGC preamble is to be transmitted simultaneously via at least a first antenna and a second antenna and the second long-preamble is to be transmitted simultaneously via at least the first antenna and the second antenna, a signal of the AGC preamble to be transmitted via the first antenna is to be transmitted via a set of subcarriers, a signal of the AGC preamble to be transmitted via the second antenna is to be transmitted via the set of subcarriers, and a relationship between the signal of the AGC preamble to be transmitted via the first antenna and the signal of the AGC preamble to be transmitted via the second antenna is cyclically-shifted in the time domain. 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 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 (103, 104) following the short-preamble and the first long-preamble, and used for conveying information regarding the first wireless packet, an AGC preamble (105A to 105D) following the signal field, and used for a second automatic gain control performed after the first automatic gain control at the second wireless communication device, a second long-preamble (106A to 106D, 107A to 107D, 108A to 108D, 109A to 109D) 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 (110A to 110D) conveying data, wherein the AGC preamble is to be transmitted simultaneously via at least a first antenna and a second antenna and the second long-preamble is to be transmitted simultaneously via at least the first antenna and the second antenna, a signal of the AGC preamble to be transmitted via the first antenna is to be transmitted via a set of subcarriers, a signal of the AGC preamble to be transmitted via the second antenna is to be transmitted via the set of subcarriers, and a relationship between the signal of the AGC preamble to be transmitted via the first antenna and the signal of the AGC preamble to be transmitted via the second antenna is cyclically-shifted in the time domain. a short-preamble used for a first automatic gain control 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 (103, 104) following the short-preamble and the first long-preamble, and used for conveying information regarding the first wireless packet, an AGC preamble (105A to 105D) following the signal field, and used for a second automatic gain control performed after the first automatic gain control at the second wireless communication device, a second long-preamble (106A to 106D, 107A to 107D, 108A to 108D, 109A to 109D) 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 (110A to 110D) conveying data, wherein the AGC preamble is to be transmitted simultaneously via at least a first antenna and a second antenna and the second long-preamble is to be transmitted simultaneously via at least the first antenna and the second antenna, a signal of the AGC preamble to be transmitted via the first antenna is to be transmitted via a set of subcarriers, a signal of the AGC preamble to be transmitted via the second antenna is to be transmitted via the set of subcarriers, and a relationship between the signal of the AGC preamble to be transmitted via the first antenna and the signal of the AGC preamble to be transmitted via the second antenna is cyclically-shifted in the time domain.