Transceiver and communication method for digital multi-carrier communication

A transceiver having internal impedance and communicating with a first device and a second device respectively through a transmission line, the transceiver comprising:

• an impedance control circuit that sets the internal impedance at either a first impedance or a second impedance, the second impedance being higher than the first impedance,
• a receiving circuit that receives a frame including a preamble, a first signal, a reference and a second signal, the frame being transmitted from the first device, the first signal including a destination regarding the second signal, and
• a channel estimation circuit that performs a channel estimation with the first device,
• wherein the receiving circuit receives the first signal while the internal impedance is being set at the first impedance by said impedance control circuit, said channel estimation unit performing the channel estimation based on said preamble,
• wherein said impedance control circuit changes the internal impedance from the first impedance into the second impedance in case that the first signal indicates the second device as the destination,
• wherein, in case that the first signal indicates the transceiver as the destination, said impedance control circuit keeps the first impedance and said channel estimation unit performs a channel estimation with the first device based on the reference before the second signal is demodulated.

A transceiver having internal impedance and communicating with a first device through a transmission line, and the first device communicating with a second device through the transmission line, the transceiver comprising:

• an impedance control means that sets the internal impedance at either a first impedance or a second impedance, the second impedance being higher than the first impedance,
• a receiving means that receives a frame including a preamble, a first signal, a reference and a second signal, the frame being transmitted from the first device, the first signal including a destination regarding the second signal, and
• a channel estimation means that performs a channel estimation with the first device,
• wherein the receiving means receives the first signal while the internal impedance is being set at the first impedance by said impedance control means, said channel estimation unit performing the channel estimation based on said preamble,
• wherein said impedance control means changes the internal impedance from the first impedance into the second impedance in case that the first signal indicates the second device as the destination,
• wherein, in case that the first signal indicates the transceiver as the destination, said impedance control means keeps the first impedance and said channel estimation unit performs a channel estimation with the first device based on the reference before the second signal is demodulated.

A communication method controlling a transceiver having internal impedance and performing communication between the transceiver and a first device through a transmission line, and the first device communicating with a second device through a transmission line, the communication method comprising:

• (a) receiving a frame including a preamble, a first signal, a reference and a second signal, the frame being transmitted from the first device, the first signal including a destination regarding the second signal, wherein the first signal is received while the internal impedance is being set at a first impedance,
• (b) performing a channel estimation with the first device based on said preamble while the internal impedance is set at the first impedance, and thereafter:
• (i) changing the internal impedance from the first impedance into a second impedance in case that the first signal indicates the second device as the destination, and
• (ii) keeping the internal impedance at the first impedance and performing a channel estimation with the first device based on the reference before the second signal is demodulated in case that the first signal indicates the transceiver as the destination.