Abstract: A data rate is to be determined depending on circumstances. A control unit (30) transmits, at a predetermined frequency, a request signal by which to supply information on a data rate to a targeted radio apparatus compatible with a variable data rate. The control unit (30) receives rate information from the targeted radio apparatus. The control unit (30) sets a data rate used in the case of transmitting data, based on the information on a data rate contained in the rate information. The control unit (30) identifies the reliability level of the data rate contained in the rate information. And when the reliability level is low, the control unit (30) lowers the frequency at which the rate request signal is transmitted.

Abstract: A weight vector computing unit derives amounts of phase rotation for a plurality of multicarrier signals, respectively, and rotates the phase of a weight vector. A combining unit weights respectively a plurality of multicarrier signals with the phase-rotated weight vector, combines weighting results, and determines a combined result. A receiving weight vector computing unit remodulates the determined result and derives a first phase difference between the plurality of multicarrier signals and a result of the remodulation. The receiving weight vector computing unit remodulates the values of pilot signals and derives a second phase difference between the plurality of multicarrier signals and a result of the remodulation. Further, the receiving weight vector derives phase rotation amounts based on the first phase difference and the second phase difference.

Abstract: A correction unit corrects the phases of received multicarrier signals, respectively, carrier by carrier. A combining unit and a computing unit performs adaptive array processing on the corrected multicarrier signals on a carrier-by-carrier basis. A derivation unit derives, carrier by carrier, a phase for correction to be used by the correction unit, based on error in the multicarrier signals which have undergone the adaptive array processing. The derivation unit updates a frequency for correction about a carrier to which a known signal is assigned, based on error in the carrier, so as to derive a phase for correction and the derivation unit also derives a phase for correction, based on the error in the carrier and the phase for correction in a carrier to which the known signal is assigned.