Abstract: A radio communication apparatus for performing transmission and reception based on radio communication includes: a power suppressor for coupling loop interference signal for attenuating signal power of a received signal to suppress the coupling loop interference signal power of the received signal; and a transceiver having a coupling loop interference signal removal function for analog domain and/or a coupling loop interference signal removal function for digital domain, for removing a coupling loop interference signal contained in a signal output from the power suppressor for coupling loop interference signal.

Abstract: In a multiple propagation wave parameter measuring method, transmission waves are radiated into an outer space. The transmission waves are received as a multiple propagation wave. Arrival directions of the transmission waves are measured on the basis of reception signals. The transmission wave arriving from one direction of the measured arrival directions is defined as a desired wave, and the transmission waves arriving from remaining directions are defined as unnecessary waves. A weight with which a reception power ratio of the desired wave to the unnecessary waves becomes maximum is calculated. The reception signals are multiplied with the weight to extract the reception signal in which the unnecessary waves are suppressed. A change in delay time of the desired wave from a transmitting device to a receiving device is calculated on the basis of the reception signal in which the unnecessary waves are suppressed.

Abstract: Received baseband signals from a plurality of antennas 111 to 11Q are linearly combined through multiplication by weighting coefficients, then a decision signal is delayed for one symbol duration, and the delayed signal is multiplied by a feedback filter coefficient wb* to generate intersymbol interference, which is subtracted from the linearly combined output y(i). The subtracted output is subjected to a signal decision to obtain a decision signal, then the difference between the input into a decision unit 17 and the decision signal is obtained as an error signal e(i), and weighting coefficients w1* to wQ* and the feedback filter coefficient wb* are estimated in a parameter estimation part 71 so that the square of the error signal e(i) is minimized.

Abstract: In a system with a spread spectrum transmitter and receiver employing composite spreading codes, the transmitter spreads, in a spreading part, a baseband modulated signal by a short code from a short code generator and a long code from a long code generator with a longer chip period than that of the short code and then transmits the spread baseband modulated signal. The receiver despreads a spread baseband received signal in a receiving part by a pair of short and long codes in one despreading part to obtain a baseband modulated signal of a direct path and despreads the spread baseband received signal by the pair of short and long codes delayed by a multipath delay time difference in the other despreading part to obtain a baseband modulated signal of a delayed path, and the baseband modulated signals thus obtained are diversity-detected to obtain a detected baseband signal.

Abstract: In a system with a spread spectrum transmitter and receiver employing composite spreading codes, the transmitter spreads, in a spreading part, a baseband modulated signal by a short code from a short code generator and a long code from a long code generator with a longer chip period than that of the short code and then transmits the spread baseband modulated signal. The receiver despreads a spread baseband received signal in a receiving part by a pair of short and long codes in one despreading part to obtain a baseband modulated signal of a direct path and despreads the spread baseband received signal by the pair of short and long codes delayed by a multipath delay time difference in the other despreading part to obtain a baseband modulated signal of a delayed path, and the baseband modulated signals thus obtained are diversity-detected to obtain a detected baseband signal.

Abstract: Sampled signals SPS of a spread-spectrum received signal are fed to matched filters 12.sub.1, to 12.sub.4, wherein they are despread. A spreading code of a desired signal is used as a despreading code in the matched filter 12.sub.1, and a plurality of spreading codes which are orthogonal to the spreading code of the desired signal and orthogonal to one another are used for despreading in the matched filters 12.sub.2 to 12.sub.4. Outputs x.sub.1 to x.sub.4 from the filters 12.sub.1 to 12.sub.4 are multipled by weighting coefficients w.sub.1 to w.sub.4 ; the multiplied outputs are linearly combined into a combined signal DCS. A coefficient control part 37 is supplied with the signals x.sub.1 to X.sub.4 to be multiplied by the weighting coefficients w.sub.1 to w.sub.4 and the combined signal DCS and determines the weighting coefficients w.sub.1 to w.sub.4 by an algorithm that minimizes the average power of the combined signal DCS under a constraint on the weighting coefficients w.sub.1 to w.sub.4.

Abstract: Good bit error performance is necessary in a spread spectrum receiver even when there is severe fast varying fading fluctuation. To achieve this, the received signal is despread and outputted as a plurality of despread signals. Signal decision is performed on the basis of the result of linear combination of the despread signals. Alternatively, a priori estimation errors are calculated by subtracting, for each despread signal, an estimated despread signal from the despread signal, and signal decision is performed on the basis of the sum of the squares of these a priori estimation errors for each despread signal. Tap coefficients are estimated by employing an RLS algorithm in which the a priori tap coefficient vector is replaced with the result of multiplying the a priori tap coefficient vector by a transition matrix.

Abstract: A baseband signal, obtained by quasi-coherent detecting a received signal, is sampled and written as a sequence of baseband signal samples into a buffer memory. For each baseband signal sample read out from the buffer memory, a maximum likelihood sequence estimation part generates a desired symbol sequence and feeds it to a transversal filter having a characteristic based on an estimated impulse response of the transmission path in correspondence with the timing of the baseband signal sample. A phase error between an estimated received signal from the transversal filter and the corresponding baseband signal sample is sequentially detected by a phase error detecting part. The phase error thus obtained is fed to an offset correcting signal generating part, which calculates an estimated offset angular frequency .DELTA..omega..sub.

Abstract: A multipath component detector detects the correlation between a received signal and a reference signal in a training period of the received signal and estimates and outputs the multipath received component levels at a plurality of timing points. A component ratio calculator calculates the ratio of each received component to the overall received power. By this, the level ratio of a specified received component can be detected. Power dissipation can be minimized by switching the detector to a differential detector or an adaptive equalizer in accordance with the result of the delay spread measurement.

Abstract: Pluralities of estimated desired and interference signal sequence candidates corresponding to the states of transition of desired and interference signals estimated to receive are sequentially generated in a state estimation part 40, from which they are provided to a desired signal estimation part 10 and an interference signal estimation part 20. These estimation parts 10 and 20 generate estimated desired and interference signals from the sequence candidates in accordance with conversion parameters from a channel parameter estimation part 50. A signal of their sum is subtracted in an error estimation part 30 from a received signal to yield an estimation error signal .epsilon.. The state estimation part 40 estimates estimated desired and interference signal sequences for the generated sequence candidates.