Abstract: A radio receiver for improving transmission performance by applying prescribed processing to received signals having reached to plural antennas concurrently, and a despreader to be mounted in the radio receiver. In such a radio receiver, the received signals are decimation-sampled, and multiplexed into a multiple-signal, which is demultiplexed and prediction processed for interpolating the values decimated in the sampling. In the despreader, the transfer functions and despreading codes are multiplied in real time, and interpolation processing and despreading processing are performed based on the filtering characteristics set as the results of the multiplication. In a radio transmission system to which the present invention is applied, it becomes possible to perform all of desired synthetic processing, phase scanning, frequency scanning and feeding point scanning adaptive to an array antenna system, without lowering the performance of the system or increasing the scale and the price of the hardware.

Abstract: In a searcher of a CDMA receiver comprising an array antenna, a voltage profile generation portion performs correlation computations of received signals for each antenna element and generates received signal voltage profiles; a phase difference estimation portion uses sample data from each voltage profile at the same time to perform correlation calculations among antenna elements and estimates the phase difference among antenna elements at the above time, and similarly estimates the phase differences among antenna elements at each time. An in-phase synthesis portion uses the phase difference estimate at a prescribed time to coordinate the phases of voltage profiles for each antenna element at the above time and performs synthesis, and similarly coordinates the phases of each antenna element voltage profile at other times and performs synthesis; and, a path detection portion detects the path timing of multiple paths based on the synthesized profile obtained by the in-phase synthesis portion.

Abstract: The present invention relates to an arrival direction estimation method using an array antenna and a DS-CDMA receiver unit using this method. The method produces an accurate estimate of the arrival direction of a desired signal regardless of reception level and high interference. In a DS-CDMA communication system for performing a transmission by a spreading process using a code having a period longer than a symbol length, received signals from an array antenna are subjected to a despreading process by despreading units. A cross-correlation function with time lags of the recieved signals is obtained by inverse-modulating despread output signals by a known symbol in an inverse modulator. An arrival direction of a received signal is estimated by an arrival direction estimation unit based on the cross-correlation function. A beam former combines the despread output signals depending on the arrival direction and outputs an output signal to a channel receiver.

Abstract: The invention provides a technique for measurement of a signal to interference power ratio wherein an SIR can be measured with a higher degree of accuracy without being influenced by a fast fading environment or an inter-station interference or noise environment.

Abstract: An array antenna system of a wireless base station in CDMA mobile communications has a beam former for forming a plurality of electric beams by applying beam forming to multipath signals received by a plurality of antenna elements of an array antenna and inputting the beams to despreading/delay-adjusting units (fingers) provided for respective path of multipaths. Each finger despreads each of the plurality of beams input thereto. A beam selector selects despread signals for which desired signal components are large from all beams of all paths, a combiner weights and combines the selected despread signals, and an decision unit decides data based upon the combined signal.

Abstract: In a CDMA wireless base station, signals that have been received by a plurality antenna elements of an array antenna on the receiving side are subjected to beam forming by a reception beam former to electrically form a plurality of uplink beams. Reception is carried out based upon the optimum beam (e.g., the beam for which the power is maximum) among the plurality of uplink beams. A transmission beam former for subjecting a transmission signal to beam forming is provided. Based upon whether an uplink reception signal is present or not, a controller performs control so as to carry out downlink beam forming, thereby forming a downlink transmission beam in a direction identical with that of the optimum uplink reception beam, or in such a manner that downlink beam forming is not carried out.

Abstract: An array antenna receiving device which compensates a phase deviation to perform an efficient beam forming while keeping phase difference information between receivers determined by the arrival direction of a user signal in a communication area to which an antenna element is directive and the array of antenna elements in a radio base station. An analog beam former provides a composite beam so that a phase difference between adjacent beams may have a fixed value determined by beams to be selected. A phase compensator provides digital signals of receivers with phase correction quantities based on any one of the digital signals so that phase differences between the antenna elements may have a fixed value.

Abstract: A multistage interference canceller and method for removing interference between users and multipath interference from received signals in multiple stages includes a plurality of despreading units which produce a received symbol vector and an estimated channel value, a synthesis unit which synthesizes the received symbol vector, an amplitude of the received symbol vector and the amplitude of the estimated value from each reverse spreading unit, and a decision unit which executes a hard decision and a soft decision according to a result of comparing the total amplitude of the received symbol vector and the total amplitude of the estimated channel value.

Abstract: A multistage interference canceller equipment and interference canceller method for use, for example, in CDMA (Code Division Multiple Access) multibeam-antenna communication system includes in each stage an interference canceller unit which has a replica signal generator which generates from an input beam signal a first interference replica signal and outputs a first error signal, and an interference removal unit which receives from another replica signal generator a second interference replica signal, multiplies that second interference replica signal by conversion coefficients and subtracts an obtained signal from the first interference replica signal to produce a second error signal so that an error signal is generated for each signal beam from the interference replica signals of a local signal beam and other signal beams to eliminate interference.

Abstract: An array antenna system of a wireless base station in CDMA mobile communications combines signals, which have been received by a plurality of antenna elements of an array antenna, upon subjecting the signals to amplitude and phase-rotation control, and despreads the combined signal. A searcher has matched filters which apply correlation operations to output signals from respective antenna elements to thereby calculate correlation signals that are correlated with a signal transmitted from a mobile station of interest. An adaptive weight calculating unit calculates adaptive weights for obtaining in-phase correlation signals from the respective antenna outputs. A beam former multiplies, by the adaptive weights, output signals from the corresponding antenna elements and combines the resulting products to output a combined signal. The combined signal is found for each path of multipaths and is input to a Rake receiver, which proceeds to identify data.

Abstract: A reference antenna element out of plural antenna elements directed to the same sector is set as a first antenna element; a receiver for frequency conversion of the signal received by the first antenna element is set as a first receiver; any antenna element different from the first antenna element is set as a second antenna element; and a receiver for frequency conversion of the signal received by the second antenna element is set as a second receiver. The output signals of the first and second receivers relative to a specific up-signal are supplied to phase compensation calculator means, which then calculates the phase compensation amount representing the phase amount of the difference between the output-signal phase difference of the first and second receivers and the input-signal phase difference of the first and second receivers.

Abstract: The invention provides a technique for measurement of a signal to interference power ratio wherein an SIR can be measured with a higher degree of accuracy without being influenced by a fast fading environment or an inter-station interference or noise environment.