Abstract: In a radio communication system employing HARQ scheme wherein the maximum number of slots is changed, a radio terminal (1) which calculates a predictive transmission rate being the predictive value of a downlink transmission rate at a future time after the receiving time of a downlink radio signal is provided with a storage unit (15A) which stores in association with a DRC a corrected transmission rate obtained by causing a defined transmission rate being a downlink transmission rate in the case of using all the maximum number of slots to reflect the probability of succeeding in decoding data using only some of the slots, and a calculation unit (142) which predicts the reception quality at the future time on the basis of the reception quality before the receiving time, obtains from the storage unit (15A) the corrected transmission rate associated with the DRC corresponding to the predicted reception quality, and calculates the predictive transmission rate from the obtained corrected transmission rate.

Abstract: When wireless communications are performed with a plurality of wireless stations using a spatial division multiple access scheme, there are included a moving speed grasp step, a priority grasp step, a channel assignment order determination step, a channel assignment order adjustment step for modifying, based on the priority grasped by the priority grasp step, so that the high-priority wireless station is placed high in the channel assignment order and a channel assignment control step for controlling, for the wireless stations after the wireless station to which a channel for frequency division multiple access has been assigned based on the channel assignment order, so that at least a channel for spatial division multiple access which has been spatially divided for the last channel is assigned.

Abstract: There is provided a first device for use in a communication system, the communication system further comprising a plurality of second devices, the system having a plurality of orthogonal frequency carriers available for transmissions, each second device having a respective carrier frequency offset estimated from signals received from the first device, each of the second devices transmitting a respective stream of symbols using the respective estimated carrier frequency offset and one or more frequency carriers selected from the plurality of orthogonal frequency carriers, the first device comprising receiver circuitry for receiving respective signals from each of the second devices; a channel estimator for generating, from the received signals, an estimate of the channel over which the signals have been transmitted; an interference estimator for generating, from the received signals, an estimate of interference at the first device caused by errors in the carrier frequency offsets estimated by each second devic

Abstract: There is provided a first device for use in a communication system, the communication system further comprising a plurality of second devices divided into a plurality of groups, the system having a plurality of orthogonal frequency carriers available for transmissions, each second device having a respective carrier frequency offset estimated from signals received from the first device, each of the second devices transmitting a respective stream of symbols using the respective estimated carrier frequency offset and one or more frequency carriers selected from the plurality of orthogonal frequency carriers, the first device comprising receiver circuitry for receiving respective signals from each of the second devices; a channel estimator for generating, from the received signals, an estimate of the channel over which the signals have been transmitted; an interference estimator for generating, from the received signals, an estimate of interference at the first device caused by errors in the carrier frequency off

Abstract: A second wireless communication device transmits a data using a plurality of carrier frequencies to a first wireless communication device which transmits by a beam with directivity. The first wireless communication device forms the beam with directivity in accordance with a wireless propagation path when receiving the data from the second wireless communication device. The second wireless communication device comprises a control unit for controlling the transmission of the data. The control unit selects at least one carrier frequency, controls the transmission of the data so as to transmit the data using the carrier frequency selected, and controls the transmission of the data so as to transmit the data using carrier frequency not selected in an immediately preceding frame when transmitting the data in a next frame.

Abstract: A channel prediction system (100) is provided with an estimation error calculator (130) which calculates an estimation error value representing the difference between a channel estimation value and a channel characteristic, and a prediction error calculator (140) for calculating a prediction error value indicating the difference between the channel prediction value calculated by a channel prediction unit (120) and a channel characteristic. The channel prediction unit (120) uses the channel prediction with priority over using the channel estimation value to calculate the channel prediction value corresponding to a future time when the estimation error value exceeds the prediction error value.

Abstract: A weight calculator (140) of a receiver (10) comprises an antenna weight processor (140A) and an equalization weight processor (140B). The antenna weight processor (140A) sets the initial values of antenna weights (w*1 to w*R) to an antenna weighting unit (115). The equalization weight processor (140B) calculates equalization weights (c*0 to c*M) by using an optimization algorithm in the state in which the initial values are held in the antenna weighting unit (115). The antenna weight processor (140A) calculates the antenna weights (w*1 to w*R) by using the optimization algorithm in the state in which the calculated equalization weights (c*0 to c*M) are held in a feed-forward unit (120A).

Abstract: A radio base station (100) according to the present invention is equipped with a determination unit (150) that compares a first signal quality of a first output signal (y1[k]) which is output by an adaptive array antenna (110) and a second signal quality of a second output signal (y2[k]) which is output by an adaptive equalizer (120) and determines whether the improvement effect of the second signal quality with respect to the first signal quality is below expectation. When the determination unit (150) determines that the improvement effect is below expectation, a controller (160) stops power supply to the adaptive equalizer (120) and the calculation of an equalization weight (c*) by a weight calculator (140), and outputs the first output signal (y1[k]) as the output signal (Out) of a receiver (101).

Abstract: An array antenna apparatus which has an away antenna formed by a plurality of antenna elements, and subjects received signals, which are received by the antenna elements, to weighting using array weights of complex numbers. The array antenna apparatus includes a delay device for delaying a signal; a weighting device for separating ea of the received sirs into first and second received signals, delaying any one of the first and second received signals by using the delay device, so as to weight the first and second received signals at different timings; and a first adding device for adding the weighted first and second received signals to each other. The weighting device weights any one of the first and second received signals by using the real part of the relevant array weight, and weights the other received signal by using the imaginary part of the array weight.

Abstract: A wireless communication apparatus 100 according to the present invention is provided with a reception channel coefficient variation calculation unit 130-1, . . . for calculating a variation of a reception channel coefficient calculated by a reception channel coefficient calculation unit 120-1, . . . , a transmission channel coefficient calculation unit 140-1, . . . for calculating a transmission channel coefficient at transmission by extrapolation based on the variation of the reception channel coefficient, a correction coefficient memory unit 150-1 for storing a correction coefficient based on the variation of the reception channel coefficient at reception for correcting the transmission channel coefficient at transmission, and a correction unit 170-11, . . . for correcting the transmission channel coefficient at transmission calculated by the transmission channel coefficient calculation unit 140-1, . . . based on the correction coefficient stored in the correction coefficient memory unit 150-1.

Abstract: A wireless communication apparatus 100 according to the present invention is provided with reception channel coefficient calculation units 120-1 to 120-n for calculating reception channel coefficients of respective antennas, transmission channel coefficient calculation units 130-1 to 130-n for calculating transmission channel coefficients of respective antennas by extrapolation based on variations of the reception channel coefficients, absolute value calculation units 140-1 to 140-n for calculating absolute values of the transmission channel coefficients, a threshold calculation unit 150 for calculating a threshold based on the reception channel coefficients, comparison units 160-1 to 160-n for comparing the absolute values and the threshold, and transmission channel coefficient correction units 170-11 to 170-1n, when the absolute values are greater than the threshold, for correcting the transmission channel coefficients so as to match the absolute values to the threshold.

Abstract: A wireless communication method of a wireless communication apparatus (100) for performing wireless communication with a plurality of terminals based on the adaptive modulation scheme by using the space division multiple access scheme includes a data rate acquisition step of acquiring a data rate in a downlink to each terminal, a data rate estimation step of estimating a data rate in the downlink to each terminal based on the uplink signal quality of each terminal, a data rate difference calculation step of calculating, with respect to each terminal, a difference between the data rate estimated at the data rate estimation step and the data rate acquired at the data rate acquisition step and a channel assignment control step of controlling channel assignment to each terminal based on the difference in data rate calculated at the data rate difference calculation step.

Abstract: A wireless communication method for a wireless communication apparatus to communicate wirelessly with a corresponding wireless communication apparatus with adaptively selecting a modulation scheme from a plurality of modulation schemes, comprising: a step of grasping a quality of a received signal; a step of selecting a first modulation scheme based on the grasped quality of the received signal; a step of calculating a retransmission rate of received signals in the first modulation scheme; a step of determining an estimated throughput from the calculated retransmission rate based on relations between throughput and retransmission rate; a step of comparing the estimated throughput with a throughput in a second modulation scheme having a smaller multi-value number than that in the first modulation scheme; and a step of performing wireless communication in either the first modulation scheme or the second modulation scheme depending on the comparison result.

Abstract: When wireless communications are performed with a plurality of wireless stations using a spatial division multiple access scheme, there are included a moving speed grasp step, a priority grasp step, a channel assignment order determination step, a channel assignment order adjustment step for modifying, based on the priority grasped by the priority grasp step, so that the high-priority wireless station is placed high in the channel assignment order and a channel assignment control step for controlling, for the wireless stations after the wireless station to which a channel for frequency division multiple access has been assigned based on the channel assignment order, so that at least a channel for spatial division multiple access which has been spatially divided for the last channel is assigned.

Abstract: An array antenna apparatus which has an away antenna formed by a plurality of antenna elements, and subjects received signals, which are received by the antenna elements, to weighting using array weights of complex numbers. The array antenna apparatus includes a delay device for delaying a signal; a weighting device for separating ea of the received sirs into first and second received signals, delaying any one of the first and second received signals by using the delay device, so as to weight the first and second received signals at different timings; and a first adding device for adding the weighted first and second received signals to each other. The weighting device weights any one of the first and second received signals by using the real part of the relevant array weight, and weights the other received signal by using the imaginary part of the array weight.

Abstract: An adaptive array antenna apparatus for performing adaptive control based on received signals received by a plurality of antenna elements which form an array antenna. The apparatus includes a computation part for computing an error of the received signals at different timings; an error comparison part for comparing the errors at the different timings with each other; and a weighting synthesizing part for performing weighting synthesis based on results of the comparison. Based on the results of the comparison, the computation part releases at least a part of computation resources required for the computation of the errors, and terminates the computation of the errors. Typically, the computation part performs the release of the computation resources when it is determined that the error has a minimum value, and terminates the computation of the errors.

Abstract: In a mobile communication terminal for performing wireless communication by receiving wireless signals according to CDMA communication system containing pilot signals by an antenna array containing a plurality of antenna elements (1-1 to 1-N), despreading processing is performed on received signals x1 to XN at each of the antenna array elements (1-1 to 1-N) according to a predetermined despreading code. An array response vector composed of pilot signals which are extracted by an array response vector detecting section for each of the antenna elements (1-1 to 1-N) represents the arriving direction of wireless signals. In order to form a directivity pattern of the antenna array containing antenna elements (1-1 to 1-N), a weighting operation is performed according to the array response vector. By doing this, it is possible to control the antenna array directivity pattern stably for performing wireless communication by receiving wireless signals according to a CDMA communication system.

Abstract: An adaptive array wireless communication apparatus able to suitably select antenna elements, small in amount of processing, fast in convergence speed, and suitable for transmission/reception, and a method of the same, which controls the directionalities of array antenna elements based on array weights, controls an antenna element selecting unit 23 so that the antenna elements are intermittently determined, and adjusts a period of determination of the antenna elements based on information of the antenna elements determined at a controlling unit 26.

Abstract: A wireless communication device for transmitting/receiving data uses a plurality of carrier frequencies in a time division duplex scheme. The wireless communication device includes a scheduler for selecting a slot of at least one carrier frequency for transmission of the data; and transmission data assignment means for assigning the data to the slot of the carrier frequency selected by the scheduler and making a slot of a carrier frequency not selected by the scheduler empty.

Abstract: To realize an adaptive antenna array system which improves reception quality of desired signals by properly suppressing interference signals. The system includes: a signal detection section which detects base station signals from signals received by antenna elements; a control section which selects desired signals and interference signals to be cancelled from among the detected base station signals; a spatial signature detection section which detects spatial signatures of the desired signals and the interference signals to be cancelled; a virtual-signal generation section which generates virtual-signals for the interference signals to be cancelled using the spatial signatures thereof; an array weight generation section which generates array weights for the antenna elements by multiplying the inverse matrix of a correlation matrix of the virtual-signals by the spatial signatures of the desired signals; and a signal combining section which combines the received signals using the array weights.