Hitachi-kokusai Electric Inc.

Nec Corporation

Yoichi Kushioka

Koji Yotsumoto

Mitsuhiro Takashima

Hirotaka Sato

Yoshiaki Doi

Kimihiko Kono

A synchronization signal conversion device comprises a first communication device and a second communication device. The first communication device acquires, from the received GPS signals, time synchronization information synchronized to a GPS reference time, and wirelessly transmits the time synchronization information at a frequency different from that of the GPS signals. The second communication device receives the radio signals from the first communication device and acquires the time synchronization information, synchronizes internal time information to the GPS reference signal on the basis of the time synchronization information, and generates pseudo-GPS reception signals including satellite information and outputs the signal to a reception-side base station device such that the synchronized internal time information and pre-stored position information are acquired at the base station device.

Synchronization signal conversion device

To provide a device for radio communication using a plurality of antennas, in which: an amplitude/phase adjuster () and an amplitude/phase controller () control the amplitude and the phase of signals input from at least two antennas such that a directivity, allowing a desired signal to be obtained; an amplitude/phase adjuster () and an amplitude/phase controller () control the amplitude and the phase of the signals input from the antennas such that an arrival direction of the desired signal becomes a null point and that a directivity, allowing a signal other than the desired signal to be obtained; a signal synthesizer () combines the signals; a signal synthesizer () combines the signals; and a desired signal generator removes a signal from the signal synthesizer () from a signal from the signal synthesizer ().

Device for radio communication using a plurality of antennas

In a noise canceller device, interference signal adjustment units adjust delay, phase and amplitude of a signal received by a sub antenna under different conditions to obtain adjustment signals, and subtract the adjustment signals from a signal received by a main antenna to obtain differential signals. An average power calculation unit calculates an average power for each of the differential signals. An optimal condition search unit determines the values of delay, phase and amplitude that result in the minimum average power, and sets the values in an optimal interference signal adjustment unit. The optimal interference signal adjustment unit adjusts the signal received by the sub antenna using optimal values for delay, phase and amplitude to obtain an optimal adjustment signal. A cancellation unit subtracts the optimal adjustment signal from the signal received by the main antenna to remove interference signals, and outputs a desired signal to a host device.

Noise canceller device

In a noise canceler, interference signals received by sub-antennasare cross-correlated by a first correlation-value calculation unit and the peaks of the interference signals are detected by a first peak detector. Interference signal information is acquired by a first-interference-signal information acquisition unit and the interference signals are synthesized by an interference signal synthesizer. A signal received by a main antenna and the synthesized interference signal are correlated by a second correlation-value calculation unit and the peak of the synthesized interference signal is detected by a second peak detector. The interference signal information is acquired by a second interference-signal-information acquisition unit and an interference signal replica is generated by an interference signal replica generator. The interference signal replica is subtracted by an interference signal removal unit from the signal received by the main antenna.

Noise canceler

A noise canceller device for removing interference signals from other systems and improving communication quality of a desired signal is provided. The noise canceller device comprises a first calculation unit performing cross-correlation processing on interference signals received by sub-antennas, a first peak detection unit detecting peaks of the interference signals, a first information acquisition unit acquiring first interference signal information, a composition unit composing the interference signals, a second calculation unit performing correlation processing between a signal received by a main antenna and the composed interference signal, a second peak detection unit detecting a peak of the composed interference signal, a second information acquisition unit acquiring second interference signal information, an interference signal replica generation unit generating an interference signal replica, and a removal unit subtracting the interference signal replica from the received signal by the main-antenna.

A power limiting circuit includes: a maximum value prediction filter section (MVPFS) interpolating data of one branched digital input signal; a maximum value detection section detecting maximum value of an output of the MVPFS and a time detection position thereof every constant period; a threshold subtraction section subtracting a threshold from detected maximum value and outputting a peak signal (zero when the subtraction result is negative); a coefficient selection section weighting the peak signal according to time detection position; a complex filter section limiting the weighted peak signal within a band of the input signal; a filter coefficient calculation section calculating filter coefficients of the complex filter section; a delay adjustment section delaying another of the branched input signals by a time period required for calculating the band-limited peak signal; and a subtraction section subtracting the band-limited peak signal from the other of the branched input signals subjected to delay.

Power limiting circuit

A communications device for generating a Zadoff-Chu sequence includes a storage unit storing real and imaginary part values of exp{&#x2212;j&#xb7;(2&#x3c0;/N)&#xb7;(m/2)} for the Zadoff-Chu sequence of the sequence length N, wherein m is an integer (0&#x2266;m&#x3c;(N+1)/2); a parameter acquisition unit acquiring a sequence number u, data number k, cyclic shift amount &#x394; and cyclic shift number Ncs; a phase position detecting unit detecting a phase position of the Zadoff-Chu sequence with acquired parameters; and a sequence determination unit determining m to read a real and an imaginary part value in the storage unit based on the phase position and determining a plus/minus sign of each of the real and the imaginary part value. The device further includes a sequence acquisition unit acquiring the Zadoff-Chu sequence by using the real and the imaginary part values according to m determined by the sequence determination unit and the signs thereof determined.

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Tokyo, Japan

Yoichi Kushioka