Wireless communication device and wireless communication method

A wireless communication device, comprising:

• a receiver configured to receive a first frame containing notification information to specify the wireless communication device and a second wireless terminal and a second frame for channel estimation, from a third terminal;
• and
• a transmitter configured to transmit a third frame in response to the first frame to the third wireless terminal, which contains first channel information based on the second frame,
• wherein the third frame is multiplexed with a fourth frame transmitted in response to the first frame from the second wireless terminal, and
• wherein
• the first frame contains first information to specify a bit pattern of a preamble of the third frame and a bit pattern of a preamble of the fourth frame, the transmitter transmits the third frame having the preamble having the bit pattern specified by the first information, the bit pattern of the preamble of the third frame is orthogonal to the bit pattern of the preamble of the fourth frame transmitted from the second wireless terminal, and the third frame and the fourth frame are transmitted in same frequency band, or
• the first frame contains second information to specify a first subcarrier used for transmission of a preamble of the third frame and a second subcarrier orthogonal to the first subcarrier, used for transmission of a preamble of the fourth frame, the transmitter transmits the preamble of the third frame via the first subcarrier specified by the second information, the third frame having a bit pattern for channel estimation,
• and a part following the preamble of the third frame is transmitted in same frequency band as that of a part following the preamble of the fourth frame.

A wireless communication method, comprising:

• transmitting a first frame containing notification information to specify a first wireless terminal and a second wireless terminal and a second frame for channel estimation;
• and
• receiving a third frame transmitted from the first wireless terminal in response to the first frame and a fourth frame transmitted from the second wireless terminal in response to the first frame,
• wherein the third frame and the fourth frame are transmitted in a multiplexing scheme by the first wireless terminal and the second wireless terminal,
• wherein the third frame contains first channel information estimated based on the second frame,
• wherein the fourth frame contains second channel information estimated based on the second frame, and
• wherein
• the first frame contains first information to specify a preamble of the third frame and a preamble of the fourth frame, the preamble of the third frame and the preamble of the fourth frame include mutually-orthogonal bit patterns for channel estimation, the method comprises receiving the third frame and the fourth frame whose preambles include the bit patterns specified by the first information from the first terminal and the second terminal in same frequency band, or
• the first frame contains second information to specify a first subcarrier used for transmission of a preamble of the third frame and a second subcarrier orthogonal to the first subcarrier, used for transmission of a preamble of the fourth frame, the method comprises receiving the preambles of the third frame and the fourth frame via the first subcarrier and the second subcarrier specified by the second information from the first wireless terminal and the second wireless terminal,
• and receiving parts following the preambles of the third frame and the fourth frame in same frequency band.

A wireless communication device, comprising:

• a transmitter configured to transmit a first packet containing notification information to specify a first wireless terminal and a second wireless terminal and transmit a second packet for channel estimation after the first packet is transmitted;
• and
• a receiver configured to receive a third packet transmitted from the first wireless terminal in response to the first packet and a fourth packet transmitted from the second wireless terminal in response to the first packet, after the second packet is transmitted,
• wherein the third packet and the fourth packet are transmitted in a multiplexing scheme by the first wireless terminal and the second wireless terminal,
• wherein the third packet contains first channel information estimated based on the second packet, wherein the fourth packet contains second channel information estimated based on the second packet, and
• wherein a preamble of the third packet and a preamble of the fourth packet include mutually-orthogonal bit patterns for channel estimation, and the receiver receives the third packet and the fourth packet whose preambles include the bit patterns specified by the wireless communication device from the first terminal and the second terminal in a same frequency band, or
• the receiver receives preambles of the third packet and the fourth packet transmitted via a first subcarrier used for transmission of a preamble of the third packet and a second subcarrier orthogonal to the first subcarrier used for transmission of a preamble of the fourth packet respectively specified by the wireless communication device from the first wireless terminal and the second wireless terminal, the preambles include any bit patterns for channel estimation, and receives parts following the preambles of the third packet and the fourth packet in a same frequency band.

A wireless communication device, comprising:

• a receiver configured to receive a first packet containing notification information to specify the wireless communication device and a second wireless terminal and receive a second packet tor channel estimation after the first packet is received, from a third wireless terminal;
• and
• a transmitter configured to transmit a third packet to the third wireless terminal, which contains first channel information based on the second packet in response to the first packet after the second packet is received,
• wherein the third packet is multiplexed with a fourth packet transmitted from the second wireless terminal, and
• wherein the transmitter transmits the third packet having a preamble having a bit pattern specified by the third wireless terminal, the bit pattern of the preamble of the third packet is orthogonal to a bit pattern of a preamble of the fourth packet transmitted from the second wireless terminal, and the third packet and the fourth packet are transmitted in a same frequency band, or
• the transmitter transmits a preamble of the third packet via a first subcarrier specified by the third wireless terminal, the third packet having a bit pattern for channel estimation, and a part following the preamble of the third packet is transmitted in a same frequency band as that of a part following a preamble of the fourth packet transmitted via a second subcarrier from the second wireless terminal, the second subcarrier orthogonal to the first subcarrier.

A wireless communication method, comprising:

• transmitting a first packet containing notification information to specify a first wireless terminal and a second wireless terminal and transmitting a second packet for channel estimation after the first packet is transmitted;
• and
• receiving a third packet transmitted from the first wireless terminal in response to the first packet and a fourth packet transmitted from the second wireless terminal in response to the first packet, after the second packet is transmitted,
• wherein the third packet and the fourth packet are transmitted in a multiplexing scheme by the first wireless terminal and the second wireless terminal,
• wherein the third packet contains first channel information estimated based on the second packet, and the fourth packet contains second channel information estimated based on the second packet, and
• wherein a preamble of the third packet and a preamble of the fourth packet include mutually-orthogonal bit patterns for channel estimation, and the method comprising receiving the third packet and the fourth packet whose preambles include the bit patterns specified by the wireless communication device from the first terminal and the second terminal in a same frequency band, or
• the method receiving preambles of the third packet and the fourth packet transmitted via a first subcarrier used for transmission of a preamble of the third packet and a second subcarrier orthogonal to the first subcarrier used for transmission of a preamble of the fourth packet respectively specified by the wireless communication device from the first wireless terminal and the second wireless terminal, the preambles include any bit patterns for channel estimation, and receiving parts following the preambles of the third packet and the fourth packet in a same frequency band.