Abstract: A radio communication system includes a multiple number of transmitting apparatus and a receiving apparatus including a multiple number of receive antennas, in which the transmitting apparatus generates a reference signal that is obtained by adding a different time shift to a known signal between the transmitting apparatus and the receiving apparatus, multiplexes a data signal with the reference signal and transmits the resultant signal. The receiving apparatus separates reference signals multiplexed on the signals received from the multiple transmitting apparatus, and estimates channel information from the reference signals, which have been transmitted through common frequencies in part or whole of the signal spectra. Then, the data signal is decoded based on the estimated channel information.

Abstract: A receiver apparatus includes a first frequency response estimator configured to calculate a first frequency response estimation value using a reference signal, a duration extractor configured to determine an estimation duration by extracting at least one duration from among a plurality of duration candidates into which a predetermined maximum delay time is divided, and a second frequency response estimator configured to calculate a second frequency response estimation value as a frequency response estimation value for demodulation using the first frequency response and the estimation duration. The receiver apparatus thus performs high-precision channel estimation even if a variety of PDPs occur with time.

Abstract: A receiver apparatus includes a first frequency response estimator configured to calculate a first frequency response estimation value using a reference signal, a duration extractor configured to determine an estimation duration by extracting at least one duration from among a plurality of duration candidates into which a predetermined maximum delay time is divided, and a second frequency response estimator configured to calculate a second frequency response estimation value as a frequency response estimation value for demodulation using the first frequency response and the estimation duration. The receiver apparatus thus performs high-precision channel estimation even if a variety of PDPs occur with time.

Abstract: A control station device performs communications controlled by a central control station device. The control station device acquires information related to a control station device that becomes an interference source to a coverage area controlled by the control station device. The control station device notifies the central control station device of the information related to the control station device that becomes the interference source. The control station device acquires, from the central control station device, information related to a possibility of communications thereof. In this way, the control station device is provided that forms the communication system excellent in frequency usage efficiency based on interference source information and the like indicating an inter-cell interference status measured at each cell.

Abstract: There is provided a first base station device in a communication system in which, within a wide coverage area of a first cell, at least one second cell having a coverage area narrower than the coverage area of the first cell is present, the first base station device controlling the first cell. The first base station device supplies information concerning a transmission weight to a second base station device which controls the second cell, the transmission weight being used by a terminal device which transmits a data signal to the second base station device. With this configuration, in a system in which a plurality of cells with a small zone radius are present in a cell with a large zone radius, it is possible to determine, with a small amount of calculations, transmission and reception weights that can eliminate interference received by the cell with a large zone radius from the plurality of cells with a small zone radius.

Abstract: In a communication system, a first cell that covers a wide region includes, in a cover region thereof, a second cell that covers a smaller region than the first cell, one first terminal device or more positioned in the first cell receive a signal on which precoding has been performed and that is transmitted by a first base station apparatus that controls the first cell, and one second terminal device or more positioned in the second cell receive a signal on which precoding has been performed and that is transmitted using the same frequency as in the first cell by a second base station apparatus that controls the second cell. The communication system determines the number of streams to be transmitted by the second base station apparatus on the basis of information regarding the number of streams to be transmitted by the first base station apparatus. As a result, in a system in which interference between cells exists, interference may be reduced with a simple structure using transmit and receive filters.

Abstract: A wireless communication system includes a plurality of transmission devices, each of which transmits signals resulting from precoding performed for a plurality of resources, and a reception device that receives at least one desired signal and a plurality of undesired signals, the number of which is greater than or equal to the degree of freedom that the plurality of resources have. The at least one desired signal and the plurality of undesired signals have been transmitted from the transmission devices. The plurality of resources is the unit of precoding. At least one of the plurality of transmission devices transmits signals on each of which precoding has been performed such that equivalent channel vectors of the plurality of undesired signals in the reception device are made to be orthogonal to a reception weight vector used in the reception device.

Abstract: A radio communication system includes a multiple number of transmitting apparatus and a receiving apparatus including a multiple number of receive antennas, in which the transmitting apparatus generates a reference signal that is obtained by adding a different time shift to a known signal between the transmitting apparatus and the receiving apparatus, multiplexes a data signal with the reference signal and transmits the resultant signal. The receiving apparatus separates reference signals multiplexed on the signals received from the multiple transmitting apparatus, and estimates channel information from the reference signals, which have been transmitted through common frequencies in part or whole of the signal spectra. Then, the data signal is decoded based on the estimated channel information.