Sanyo Electric Co., Ltd.

Hiroyasu Yoshida

Kazuhisa Ishiguro

Yoshiaki Takahashi

Yasunori Akatsuka

Daiki Takiguchi

The present invention aims to provide a radio base station that has equivalently high reception sensitivity without increasing the number of antenna elements while keeping the utilization efficiency of time slots high. The radio base station comprises a radio unitand a radio unitTwo time slots, one at each radio unit, are allocated to a mobile station. After a signal transmitted from the mobile station is received and demodulated, a piece of data received by the radio unitis compared with a piece of data received by the radio unitso that one of the pieces of data that has fewer errors is selected.

Diversity receiving radio base station with high reception sensitivity and high time slot utilization efficiency

A received spread spectrum signal is despread by a first despreading circuit, and according to this first despread signal, a synchronizing signal generator (PLL) generates a signal in phase with the first despread signal. According to the output signal from the synchronizing signal generator, a spreading code generator generates a plurality of Spreading codes out of phase with one another. The plurality of spreading codes are supplied to a second despreading circuit, which despreads the received spread spectrum signal by the plurality of spreading codes, and thus, a plurality of second despread signals are obtained. A correlation detector detects the correlation between the spread spectrum signal and each of the plurality of spreading codes on the basis of the plurality of second despread signals. According to the correlation results, a control circuit determines the direction in which to shift the phase of the plurality of spreading codes with respect to the received spread spectrum signal. The control circuit sequentially shifts the phases of the spreading codes until a spreading code with an optimum phase is obtained which is then supplied to the first despreading circuit and maintained. In this way, a spreading code with an optimum phase is used in the first despreading circuit, and the spread spectrum signal is despread to the original bandwidth accurately.

Spread spectrum signal receiving apparatus

In a spread spectrum signal receiver, a frequency divider circuit divides the frequency of the output signal of a VCO having a phase synchronized with that of the output signal of first multiplier. A first spreading code generating circuit generates a spreading code in response to the output signal of the frequency divider circuit. A second spreading code generating circuit generates first through third spreading codes in response to the spreading code. A selection circuit selects one of the first through third spreading codes. A second multiplier despreads the spectrum using the spreading code output from the selection circuit. A correlation detector circuit detects correlation from the output signal of the second multiplier and a control signal generates a delay or advance control signal in response to the detected correlation. The frequency dividing ratio of the frequency divider circuit is switched according to the delay or advance control signal. The timing of generating a spreading code can be regulated by changing the frequency dividing ratio, and then the timing of the spreading code of the transmitter side and that of the receiver side coincide.

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Ota, Japan

Hiroyasu Yoshida