Abstract: According to an aspect of the present invention, there is provided with a base station which communicates with radio terminals through time frames for transmission by using a plurality of frequency channels, including: a reception section configured to receive communication quality information indicating communication quality of one or more frequency channels from each the radio terminal; a scheduling section configured to schedule frequency channels to be assigned to the respective radio terminals based on the communication quality information received from the respective radio terminals; a signal generation section configured to generate assignment status signals indicating whether or not respective frequency channels are already assigned in a second time frame next to a first time frame; and a reporting section configured to report the assignment status signals for the frequency channels to each the radio terminal through the first time frame

Abstract: There is provided with a radio terminal which is assigned one or more frequency channel to carry out downlink communication with a base station, including: a reception unit configured to receive signals of a plurality of frequency channels from the base station; a quality measuring unit configured to measure communication quality of each frequency channel; a priority setting unit configured to set priority for each frequency channel; a transmission unit configured to transmit communication quality information indicating communication quality of each frequency channel in descending order of priority to the base station; and a control unit configured to provide a signal instructing to stop transmission of the communication quality information to the transmission unit upon receiving a transmission stop instruction for instructing to stop transmission of the communication quality information from the base station.

Abstract: A radio communication system includes a first radio communication apparatus comprising a data generating unit generating transmit data, a mapping unit allocating a modulation signal generated according to the transmit data to two subcarriers between which a frequency difference of a first frequency is, an IFFT unit performing IFFT on the modulation signal allocated to each subcarrier to generate an OFDM signal having a second frequency higher than the first frequency, and a transmitter transmitting a radio frequency signal obtained from the OFDM signal, and a second radio communication apparatus comprising a receiver downconverting the radio frequency signal into a baseband signal, an AD converter sampling the baseband signal at the first frequency, a FFT unit performing FFT on an output of the AD converter to extract a receive signal, and a data demapping unit demapping the receive signal to obtain receive data.

Abstract: An object of the present invention is to provide a wireless communication system, a wireless communication system, comprising: one or more wireless base station; and a plurality of wireless terminals capable of communicating with said wireless base station by wireless, two or more of said wireless terminals capable of communicating with each other by wireless thereby forming a wireless terminal group; wherein said wireless base station has a representative determination unit configured to determine at least one wireless terminal belonging to said wireless terminal group as a representative terminal; and said representative terminal receives first frames transmitted from other wireless terminals belonging to said wireless terminal group, and transmits the received first frames to said wireless base station.

Abstract: According to an aspect of the present invention, there is provided with a radio receiver including: one or more antenna which receives radio signals; a plurality of filters which selectively output signals in respective reception bands from the radio signals received by the antenna, adjacent reception bands partially overlapping each other; a plurality of A/D converters disposed correspondingly to the filters to convert the signals output from the respective filters to digital signals; extracting units which extract signal components of a boundary radio signal spreading across at least two reception bands adjacent to each other from digital signals associated with the at least two reception bands adjacent to each other; a combining unit which combines the signal components extracted by the extracting units to restore the boundary radio signal; and a demodulation unit which demodulates the boundary radio signal restored by the combining unit.

Abstract: There are provided a radio communication device and method including: modulating packets with a modulation scheme assigned in advance; transmitting modulated packets; receiving packets; estimating a channel state by utilizing received packets; selecting a first modulation scheme having a larger number of bits to be allocated per one symbol than the number of bits to be allocated in the modulation scheme assigned in advance, in case where the channel state satisfies a first modulation scheme change threshold, selecting a second modulation scheme having a smaller number of bits to be allocated per one symbol than the number of bits to be allocated in the modulation scheme assigned in advance, in case where the channel state satisfies a second modulation scheme change threshold; and modulating packets that satisfy an predetermined application condition, with the first or the second modulation scheme.

Abstract: An orthogonal frequency division multiplexing (OFDM) signal transmission apparatus which transmits OFDM signals by using a plurality of transmission antennas includes a subcarrier setting device which sets signals for subcarriers so as to use some of the subcarriers of the OFDM signals as pilot subcarriers to transmit pilot signals and use the remaining subcarriers as data subcarriers to transmit data signals, the subcarrier setting device changing polarities of signals for the pilot subcarriers for each transmission antenna.

Abstract: A wireless communication apparatus includes a wireless communication unit configured to conduct wireless communication by selecting one wireless scheme among a plurality of wireless schemes capable of conducting wireless communication, a storage which stores information obtained by classifying the plurality of wireless schemes into a plurality of classes, based on priorities set to the plurality of wireless schemes in accordance with at least one parameter, and a selector which selects one wireless scheme by which the wireless communication unit conducts wireless communication, based on classes stored in the storage.

Abstract: A burst signal receiver comprises a correlation computation unit configured to compute a correlation value between a received known signal and a generated known signal, a moving average calculator to moving-average the correlation value to obtain a moving average value, a peak detector to detect a peak value of the moving average value and a peak position thereof for each of the constant periods; and a synchronization determination unit configured to determine a synchronization position according to a given condition using the peak value and the peak position.

Abstract: An OFDM receiver apparatus comprises a receiver to receive an OFDM signal, an estimator to estimate a distortion, a distortion compensator subjecting the sub-carrier to distortion compensation according to a control signal to generate a distortion-compensated sub-carrier, a demodulator to demodulate the distortion-compensated sub-carrier, an estimator to generate first phase distortion information, using the distortion-compensated sub-carrier and the distortion information, a weighting synthesizer to weight the first phase distortion information by weighting factors with time function over symbol intervals and then synthesize the first phase distortion information, to generate second phase distortion information, and a control signal generator to generate the control signal using the distortion information and the second phase distortion information.

Abstract: An object of the present invention is to provide a wireless communication system, a wireless communication system, comprising: one or more wireless base station; and a plurality of wireless terminals capable of communicating with said wireless base station by wireless, two or more of said wireless terminals capable of communicating with each other by wireless thereby forming a wireless terminal group; wherein said wireless base station has a representative determination unit configured to determine at least one wireless terminal belonging to said wireless terminal group as a representative terminal; and said representative terminal receives first frames transmitted from other wireless terminals belonging to said wireless terminal group, and transmits the received first frames to said wireless base station.

Abstract: A wireless communication system which transmits and receives a signal by using a plurality of wireless apparatuses, comprising: a first wireless apparatus group having a plurality of transmitting apparatuses, each transmitting a wireless signal based on a first control signal, said first wireless apparatus group forming a first ad-hoc network between said transmitting apparatuses; and a second wireless apparatus group having a plurality of destination apparatuses, each receiving the wireless signal transmitted from said first wireless apparatus group, said second wireless apparatus group transmitting and receiving the wireless signal received by said destination apparatuses based on a second control signal, and said second wireless apparatus group forming a second ad-hoc network between said destination apparatuses different from said first ad-hoc network.

Abstract: One of objects of a wireless communication apparatus according to the present invention is to realize stable communication regardless of received signal strength indication and information amount.

Abstract: An object of the present invention is to prevent congestion of networks and to effectively use a plurality of autonomous distributed wireless networks.