A radio receiver includes a plurality of antenna elements for receiving a radio signal from a radio transmitter; a setting part changing an impedance of at least one of the plurality of antenna elements according to an instruction signal; a measuring part measuring a change in throughput in a received signal caused due to the change in the impedance; and an instruction part providing the instruction signal which is changed in response to the measurement result.
A MIMO receiver, a MIMO reception method and a wireless communication system capable of accurate MMSE control even when each transmit antenna uses a different chip power ratio in MIMO filter reception. A correction coefficient calculator receives as input the chip power ratio of each transmit antenna, and estimates such pilot power that renders the chip power ratio of each transmit antenna equal to that of a reference transmit antenna. Thereby, the correction coefficient calculator calculates a correction coefficient .beta..sub.m to correct the actual pilot power of each transmit antenna. A weight calculator receives as input transmission channel impulse responses transferred into frequency domain by FFT sections, chip noise power estimated by a chip noise estimation section, and the correction coefficient .beta..sub.m obtained by the correction coefficient calculator. The weight calculator calculates filter weights according to the minimum mean square error (MMSE) criterion.
