Hokkaido University

Sanyo Electric Co., Ltd.

Other

Sanyo Electric O., Ltd.

Takeo Ohgane

Yasutaka Ogawa

Yoshiharu Doi

Toshihiko Nishimura

Jun Kitakado

Masashi Iwami

Seigo Nakao

Hiroshi Nishimoto

Yoshiharu c/o Sanyo Electric Co Ltd Doi

A radio unit () separates a signal from a specific terminal among signals from array antennas (#-#) based on a reception weight vector calculated by a reception weight vector calculator (). A reception response vector calculator () derives a reception response vector of a propagation path for the signal from the specific terminal. A transmission response vector estimator () regards an estimation result of the reception response vector calculator () as a composite waveform of a function of a plurality of frequencies, determined in accordance with a Doppler frequency, and predicts a transmission response vector at a time point of transmission by obtaining coefficients of respective function. A transmission weight vector calculator () controls antenna directivity in transmission, based on a prediction result of the transmission response vector estimator ().

Radio base system, transmission directional control method, and transmission directional control program

When once determined to be free of any demodulation error by an interference removing unit provided user by user, a replica signal calculated by the interference removing unit is subtracted from an input signal vector, and a calculated user signal is output as it is as a final user signal. When it is determined by the interference removing unit that there is a demodulation error, the user signal is again calculated by the interference removing unit of an interference canceller of a next stage. As subtraction of the replica signal corresponding to the user signal having a demodulation error from the input signal vector is inhibited, precision of the interference wave removal can be improved.

Radio reception system

A plurality of antennas transmit multicarrier signals composed of a plurality of streams. An IF unit acquires, per carrier, a channel matrix having elements the number of which is determined by the number of a plurality of transmitting antennas and the number of a plurality of receiving antennas provided in a receiving apparatus. A baseband processing unit derives a common autocorrelation matrix for the channel matrix acquired per carrier. The baseband processing unit derives a steering matrix by eigenvalue-decomposing the derived common autocorrelation matrix. The baseband processing unit derives, per carrier, weight vectors for a plurality of streams in a manner such that an orthonormalization is performed respectively on matrices obtained by operating the derived steering matrix on the channel matrix per carrier.

Method for deriving weight vectors to be used at the time of transmitting signals from a plurality of antennas, and transmitting apparatus and communication system utilizing said method

A correlator detects arriving timings of a desired wave and an interfering wave from a signal transmitted by the OFDM scheme. A reception response vector estimator estimates a first response vector for a signal arriving within a guard interval section from the head arriving wave and a second response vector for a signal arriving after the guard interval section from the head arriving wave out of the desired wave, and also a third response vector for a signal arriving within the guard interval section from the head arriving wave and a fourth response vector for a signal arriving after the guard interval section from the head arriving wave out of the interfering wave. An adaptive array block provides a weight vector based on a result of Fourier transform on the first to fourth response vectors.

Radio apparatus and adaptive array processing method

Radio receiving system

A radio equipment separates a signal of a specific terminal from signals from adaptive array antennas &num; to &num; , based on a reception weight vector calculated by a reception weight vector calculator . Reception coefficient vector calculator provides an impulse response of a signal propagation path of the specific terminal. A transmission coefficient vector estimator predicts a propagation path at the time of transmission, from the result of estimation by the reception coefficient vector calculator . The transmission weight vector calculator controls, based on the result of prediction by the transmission coefficient vector estimator , the antenna directivity at the time of transmission. Thus, degradation of error rate of the down link generated by the time difference between up/down links can be suppressed.

Growing community of inventors

Sapporo, Japan

Takeo Ohgane