Abstract: A radio transmitter-receiver wherein a pilot symbol is used in the transmitter that has undergone M-chip spreading on the frequency axis and N-chip spreading on the time axis by a spreading code of M×N chip length (where M and N are any integers equal to or greater than 2), and in the receiver, a spreading code that is not used in spreading said pilot signal is used as a despreading code to despread a received signal and then estimate noise and interference power. The spreading code that is used to spread the pilot symbol and the despreading code that is used in despreading are assigned so as to be orthogonal even if only in N chips on the time axis.

Abstract: N sub-carriers are grouped in units of predetermined quantities in order beginning with the one exhibiting the highest communication channel quality to generate an optimal group pattern on the reception side. Then, communication channel information is calculated for each of sub-carrier groups in the optimal group pattern or a quasi-optimal group pattern which is assumed to be closest to the optimal group pattern among a plurality of previously set group pattern candidates. Communication channel information is designated as modified communication channel information. Grouping information indicative of the optimal group pattern or quasi-optimal group pattern is combined with modified communication channel information to generate feedback information. On the transmission side, sub-carriers are grouped based on reproduced feedback information reproduced from the feedback information.

Abstract: A mobile communication system capable of improving the reception characteristic using a small circuit size and low power consumption is provided. The channel vector estimating section 181 estimates channel vectors in a method such as a method in which the section 181 multiplies, according to the multipath timings sent from the multipath timing detecting section, the input signal from the base-station receiving section by a complex conjugate of a known pilot signal to average the input signal (to average the input signal by de-spreading the pilot signal in the case of CDMA). The noise estimating section 182 estimates noise power using received signals and generates a Channel matrix by arranging the estimated channel vectors according to the multipath timings. The weight calculating section 184 calculates a weight matrix using the noise estimation value and the Channel matrix and sets the obtained filter weight vectors to the equalizing filter 185.

Abstract: To provide a reception method and a reception device in which a base station can correct a frequency offset contained in a reception signal and realize an excellent reception characteristic by using simple reception mechanism of a frequency region in a radio system of the frequency division multiplex type.

Abstract: A wireless apparatus 1 receives reception quality information, propagation environment information, and block error rate detection information from a wireless apparatus of the other end of communication together with a data signal, and the target error rate selecting unit 7 selects any one of a plurality of tables in which target block error rates of respective ones of a plurality of transmission modes are registered in accordance with propagation environment information. The threshold value control unit 8 controls the threshold value of the reception quality to select the transmission mode by the control amount on the basis of the target block error rate in accordance with error rate detection information. The transmission mode selecting unit 9 compares reception quality information with the threshold value, selects any one of the transmission modes, and makes the selected one into the transmission mode to the wireless apparatus of the other end of communication.

Abstract: A receiver estimates a channel quality. A transmitter amplifies a signal by a gain proportional to a difference between a required signal-to-noise power ratio and channel quality information, which is an estimation result of the channel quality, and transmits the signal so that the receiver can obtain the signal-to-noise power ratio. In this case, the receiver or the transmitter determines a roll-off rate of an adaptive filter based on the channel quality information. The transmitter uses the adaptive filter of the determined roll-off rate to filter and transmit the signal.

Abstract: A receiving apparatus is provided in which a single carrier signal is received by a plurality of receiving antennas, and multipath equalization and other cell interference suppression are carried out in a frequency domain at a same time. A plurality of antennas 1-1 to 1-N receives the single carrier signal. The DFT sections 3-1 to 3-N converts the reception signals into frequency domain signals. A channel estimating section 5 estimates a channel gain of a desired user signal by using pilot reception signals. An interference correlation matrix estimating section 6 estimates an interference correlation matrix from the pilot reception signals and a channel estimation value. A weight, calculating section. A weight calculating section 7 receives the channel estimates and the interference correlation matrix and calculates equalization weights. An equalising section 8 performs multipath equalization and other cell interference suppression to the desired user signal in a frequency domain.

Abstract: A multi-user receiving apparatus is provided for achieving a reduction in the amount of processing for single-carrier FDMA signals and an improvement in reception characteristics. A DFT unit converts single-carrier FDMA received signals of all users to signals in a frequency domain commonly. A demapping unit selects part of sub-carriers for each user from sub-carriers supplied from the DFT unit. A reception filter separates a user signal and suppresses noise. A demodulator demodulates the user signal, and detects a timing thereof.

Abstract: Filtering part 50 performs filtering by converting a received signal sampled using a predetermined number of over-samples to an over-sample number small enough to avoid frequency-domain foldover noise generation. Transmission channel estimation part 60 performs path timing detection by converting the received signal sampled using a predetermined number of over-samples to an over-sample number large enough to obtain sufficient timing resolution, converts transmission channel responses for each path timing to the frequency domain, and calculates transmission channel estimates corresponding to the subcarriers of the received signal in the frequency domain. Weight calculation part 6 receives the frequency-domain channel estimates outputted from transmission channel estimation part 60 and calculates the weights of the equalizing filter used in filtering part 50.

Abstract: A radio communication device for receiving a single-carrier signal transmitted in a partial spectrum of Nyquist frequency band, includes: an interference eliminator for eliminating interference from a received signal by spectrum reproduction of non-transmitted spectra using a symbol replica, to output an interference eliminated signal, wherein the interference includes intersymbol interference which is caused by symbols which are more than a predetermined distance away from a decision symbol point; a symbol sequence estimator for estimating a transmission symbol sequence by separating nearby intersymbol interference within the predetermined distance of the decision symbol point based on the interference eliminated signal, to output a decision signal; and a replica generator for generating the symbol replica from decoding result of the decision signal, wherein the symbol replica is fed back to the frequency-domain interference eliminator.

Abstract: A mobile communication system capable of improving the reception characteristic using a small circuit size and low power consumption is provided. The channel vector estimating section 181 estimates channel vectors in a method such as a method in which the section 181 multiplies, according to the multipath timings sent from the multipath timing detecting section, the input signal from the base-station receiving section by a complex conjugate of a known pilot signal to average the input signal (to average the input signal by de-spreading the pilot signal in the case of CDMA). The noise estimating section 182 estimates noise power using received signals and generates a Channel matrix by arranging the estimated channel vectors according to the multipath timings. The weight calculating section 184 calculates a weight matrix using the noise estimation value and the Channel matrix and sets the obtained filter weight vectors to the equalizing filter 185.

Abstract: In a MIMO receiving apparatus, signals of single carriers transmitted from a plurality of transmission antennas are received by a plurality of reception antennas (1-1 through 1-N) and then separated according to frequency domain. In this MIMO receiving apparatus, interference replicas of the antennas are eliminated from received signals (by subtractor 54) before equalizing the two-dimensional frequency domain, and distortion free signal replicas are added (by demodulating part 55) to the signals from which the interference replicas of the antennas have been eliminated after equalizing the two-dimensional frequency domain.

Abstract: Adaptive modulation part (1) modulates a signal in a modulation scheme selected based on a modulation mode, switch (2) selects a radio scheme congenial to the modulation scheme in which the signal is modulated. When the selected radio scheme is single-carrier scheme, single-carrier generation part (3) generates a single-carrier signal. When the selected radio scheme is a multicarrier scheme, multicarrier generation part (4) generates a multicarrier signal, the generated single-carrier signal or multicarrier signal is converted into a carrier band signal by quadrature modulation part (5), and the converted signal is amplified by transmission amplifier (6).

Abstract: An equalizer calculates an equalization weight using a transmission channel response vector that arranges transmission channel estimation at the detection path timing and at the neighbor path timings thereof. The equalizer realizes excellent equalization characteristics by generating a transmission channel response vector that will not be affected by MPI by use of a multipath interference canceller (MPIC) to calculate the equalization weight.

Abstract: A receiver estimates a channel quality. A transmitter amplifies a signal by a gain proportional to a difference between a required signal-to-noise power ratio and channel quality information, which is an estimation result of the channel quality, and transmits the signal so that the receiver can obtain the signal-to-noise power ratio. In this case, the receiver or the transmitter determines a roll-off rate of an adaptive filter based on the channel quality information. The transmitter uses the adaptive filter of the determined roll-off rate to filter and transmit the signal.

Abstract: An adaptive antenna receiver whose follow-up performance is improved with respect to the angle change of the arrival direction of a desired signal. An antenna weight adaptive update section (11-1) adaptively updates the antenna weight according to a signals received by each antenna element and an error signal obtained from a desired signal corrected based on transmission channel estimation. An antenna weight direction constraint section (12-1) performs the constraint process for the antenna weight obtained by the antenna weight adaptive update section (11-1) to maintain the beam gain constant in the arrival direction of the desired signal. A beamformer (2-1) receives the desired signal through an array antenna using the antenna weight which has undergone the constraint process performed by the antenna weight direction constraint section (12-1).

Abstract: An SINR estimating unit of a receiver apparatus measures first and second demodulated signals to calculate SINR (ratio of signal power to sum of interference power and noise power) for each signal sequence. A transmission parameter deciding unit decides, based on the SINR, a transmission parameter used by a transmitter apparatus for controlling the transmission for each signal sequence, and then feeds the decided transmission parameter back to the transmitter apparatus. First and second mapping units of the transmitter apparatus controls, based on the transmission parameters as fed back, the modulation level for each signal sequence.

Abstract: A transmitting device according to the present invention comprises: a coding unit which encodes a transmission information bit string to a code bit string; a low-order modulating unit which conducts low-order modulation on the code bit string outputted from the encoding unit; a first frequency domain converting unit which converts the low-order modulated signal outputted from the low-order modulating unit to a frequency domain signal; a partial spectrum selecting unit which selects a central 1/M portion (M is an integer greater than or equal to two) of a spectrum from the frequency spectrum outputted from the first frequency domain converting unit; and a first time domain converting unit which converts the spectrum selected signal outputted from the partial spectrum selecting unit to a time domain signal.

Abstract: A priority computation process computes a priority of each user for each RB (Resource Brock) using a reception SINR. A maximum priority user selection/RB allocation process selects a user with the maximum priority for an unallocated RB and allocates the RB to the user. A frequency axis/space axis unallocated RB presence determination process proceeds to scheduling for a next user if there is an unallocated RB on the frequency or space axis. A projected channel vector update process updates a projected channel vector of an unselected user by GS orthogonalization. An orthogonal coefficient computation process computes an orthogonal coefficient. A corrected SINR computation process computes a corrected SINR. A next MIMO layer priority computation process computes priorities of unselected users for a corresponding RB in the next multiple MIMO layer. The priorities of the unselected users are used in the next user scheduling processing.

Abstract: An OFDM communication system which performs appropriate feedback flexibly adapted to channel states, while suppressing an amount of feedback information. The OFDM communication system has first and second communication apparatuses. In a second receiver of the second communication apparatus, a channel quality measurement part measures channel quality for each of sub-carriers. A time variation measurement part and a frequency measurement part respectively measure variation of channel quality in a time domain and a frequency domain, respectively, and output the variation of channel quality as time variation information and frequency variation information, also respectively. Based on the measured time variation information and frequency variation information, a two-dimensional control part performs two-dimensional blocking for forming two-dimensional blocks each from plural adjacent sub-carriers which are adjacent to each other in the time domain and the frequency domain.