Patent ID: 7688909

Claim:
A radio communication system comprising: a radio transmitter including: a plurality of transmission antennas; a transmission data producing unit selectively producing (a) transmission data to be transmitted with a directive multibeam from said plurality of transmission antennas in a first mode or (b) transmission data to be independently transmitted from said plurality of transmission antennas in a second mode; an orthogonal transformation unit carrying out an orthogonal transformation on a plurality of pilot signals having an orthogonal relation to each other so as to form said directive multibeam having an orthogonal relation to each other; and a pilot multiplexing unit multiplexing said orthogonally transformed pilot signals produced by said orthogonal transformation unit and said transmission data produced by said transmission data producing unit; and a radio receiver including: a plurality of reception antennas; a channel estimation unit correlating, for each of said plurality of reception antennas, a received signal received by said reception antenna with a replica signal of each of said pilot signals to obtain a channel estimate of said directive multibeam; an inverse transformation unit carrying out an inverse transformation of said orthogonal transformation on said channel estimate of said directive multibeam obtained by said channel estimation unit to obtain a channel estimate corresponding to one of said plurality of transmission antennas; and a received signal processing unit selectively conducting (a) first received signal processing on the basis of said channel estimate of said directive multibeam obtained by said channel estimation unit and said received signal in said first mode, or (b) second received signal processing on the basis of said channel estimate corresponding to said one of said plurality of transmission antennas obtained by said inverse transformation unit and said received signal in said second mode.