Patent ID: 7907636

Claim:
A radio apparatus comprising: an input unit which inputs a plurality of combinations of control signal and data signal wherein the combination uses a plurality of subcarriers; a generation unit which generates a packet signal from the plurality of combinations inputted to said input unit in a manner that a first known signal is added to a data signal contained in a combination at the beginning among the plurality of combinations inputted to said input unit and a second known signal is added to each of the combinations other than the combination at the beginning among the plurality of combinations inputted to said input unit, in an anterior part thereof; and a transmitter which transmits the packet signal generated by said generation unit, wherein the second known signal is a part of the first known signal and uses the same subcarrier as used in the control signal contained respectively in the combinations other than the combination at the beginning, the first known signal is composed of a plurality of symbols, and different subcarriers are used in different symbols, the subcarrier used in one of the plurality of symbols forming the first known signal is identical to a subcarrier used in control signals contained in each of the combinations other than the combination at the beginning, and the subcarrier used in the other symbols forming the first known signal is different from a subcarrier used in control signals contained in each of the combinations other than the combination at the beginning, and the second known signal is defined so as to be identical to part of the first known signal corresponding to the subcarrier used in the control signals contained in each of combinations other than the combination at the beginning.