Abstract: A master device that is a fixed device belongs to any of a plurality of areas, and includes: a notification information generation unit that generates notification information including position information of a plurality of fixed devices installed in the area to which the fixed device belongs; and a communication unit that transmits a notification signal including the notification information to a mobile device at a timing different from a timing of transmission of the notification signal from another area, the mobile device being configured to estimate a position based on the notification information.

Abstract: A wireless relay station to be included in a ladder-type wireless relay network along a moving route of a moving object includes a relay control unit that includes station identification information in the wireless relay network assigned sequentially along the moving route to each of the wireless relay stations included in the wireless relay network and deployed along the moving route, configures and updates, using a first routing table that provides an address of a destination wireless relay station, a second routing table including the address, the station identification information, and an information update time, being associated with one another, of the destination wireless relay station, and provides control to share, among the wireless relay stations included in the wireless relay network, the second routing table configured and updated by each wireless relay station; and a relay communication unit that performs wireless relay communication with other wireless relay stations.

Abstract: A wireless ranging system includes a ranging terminal that transmits a wireless signal including a ranging signal and a communication signal indicating an order of ranging with respect to a first ranging target terminal and a second ranging target terminal, and a first ranging target terminal and a second ranging target terminal that, when receiving the wireless signal, respectively transmits a first response signals and a second response signals consecutively a plurality of times to the ranging terminal. For each time the ranging terminal receives each of the plurality of response signals, the ranging terminal measures an elapsed time from transmission of the wireless signal, and calculates a relative distance between the ranging terminal and the ranging target terminals from a propagation time of each of the plurality of response signals calculated using the elapsed time.

Abstract: A wireless communication device includes a transmission processing unit communicable with each of multiple communication peer devices through switching between beam directions in a time division manner, and a control unit that allows beam information representing how beams are used by the multiple communication peer devices with which the transmission processing unit is communicable to be shared by the multiple communication peer devices.

Abstract: A radio communication system according to the present invention is a radio communication system including a transmission device and a reception device, the transmission device includes a first null insertion unit that inserts a first signal that is a signal having an electric power lower than an amplitude of the data symbols, in a time direction of data symbols, and the reception device includes a null extraction unit that extracts a first symbol that is a signal in a period corresponding to the first signal, from a received signal, a signal interpolation unit that interpolates the first symbol to reproduce interference components in periods corresponding to the data symbols, and a subtraction unit that subtracts the interference components from the received signal.

Abstract: A transmitter includes: a phase rotation sequence generation unit that generates, on the basis of transmit bits being input, a phase rotation sequence in which a frequency response has a bandwidth; an up-sampling unit that changes a sample rate of the phase rotation sequence and further replicates the phase rotation sequence; and a frequency shift unit that shifts, by a specified amount of shift on a frequency axis, a frequency component of the phase rotation sequence acquired from the up-sampling unit.

Abstract: In a wireless communication system, SINR data are obtained from power measurements data, as follows: gathering first power measurements data of total power received during communications; gathering second power measurements data of in-transmission interference power; computing third power measurements data of useful power, from the first and second power measurements data; gathering fourth power measurements data of out-transmission interference power; merging the second and fourth power measurements data so as to form a set of fifth interference power data; computing a first characteristic function from the third power measurements data, and computing a second characteristic function from the fifth power measurements data; building a third characteristic function relating to the SINR data related to the transmission channel, by performing a term-by-term product of the first and second characteristic functions; computing a probability mass function from the third characteristic function.

Abstract: A radio communication system according to the present invention is a radio communication system including a transmission device and a reception device, the transmission device includes a first null insertion unit that inserts a first signal that is a signal having an electric power lower than an amplitude of the data symbols, in a time direction of data symbols, and the reception device includes a null extraction unit that extracts a first symbol that is a signal in a period corresponding to the first signal, from a received signal, a signal interpolation unit that interpolates the first symbol to reproduce interference components in periods corresponding to the data symbols, and a subtraction unit that subtracts the interference components from the received signal.

Abstract: A transmitting station includes a transmitting antenna whose orientation direction is changeable, and a controller that controls the orientation direction of the transmitting antenna according to an orientation direction of the transmitting antenna determined together with receiving stations to receive data transmitted from the transmitting antenna based on estimate values of received signal quality at receiving stations that are candidates for receiving stations to receive data transmitted from the transmitting antenna. The transmitting station can maintain received signal quality at a plurality of receiving stations at a desired value or more in a data transmission system.

Abstract: A transmitter includes: a phase rotation sequence generation unit that generates, on the basis of transmit bits being input, a phase rotation sequence in which a frequency response has a bandwidth; an up-sampling unit that changes a sample rate of the phase rotation sequence and further replicates the phase rotation sequence; and a frequency shift unit that shifts, by a specified amount of shift on a frequency axis, a frequency component of the phase rotation sequence acquired from the up-sampling unit.

Abstract: A wireless communication system includes: base stations that are a plurality of transmission devices that transmits signals including different known sequences using a same frequency; and a mobile station that is a reception device that performs channel estimation using a reception signal received from at least one of the plurality of transmission devices, an average time parameter, and at least one of a plurality of the known sequences corresponding to the plurality of transmission devices, and removes an interference signal included in the reception signal using a result of the channel estimation, the average time parameter being a parameter related to channel estimation accuracy and determined based on a moving speed of a moving one of the reception device that receives the reception signal and the transmission devices that transmits the reception signal.

Abstract: A wireless communication apparatus includes a channel-usage selection unit to select one frequency channel for each time slot from a plurality of predetermined candidate frequency channels, and a wireless communication unit to perform wireless communication by using the frequency channel selected by the channel-usage selection unit. The channel-usage selection unit selects a frequency channel that is different from a frequency channel to be used in a same time slot by an adjacent cell located at a cell interval, equal to or smaller than the predetermined first number of cells, from a cell used for the wireless communication, and allows the frequency channel selected to overlap with the frequency channel to be used in the same time slot by a remote cell located at a cell interval, greater than the first number of cells and equal to or smaller than the number of the candidate frequency channels, from a cell used for the wireless communication.

Abstract: A wireless receiving device includes a signal measurement unit; a weighting factor generation unit that generates weighting factors each for suppression of the received signals, based on measurement results of the received signals; interference suppression units that each perform, in a parallel manner, interference suppression processing on the received signals, using, one of the weighting factors; arrival detection units that are connected in one-to-one to the interference suppression units, the arrival detection units each detecting arrival of a desired signal; an arrival determination unit that determines whether the desired signal has arrived; and a demodulation processing unit that demodulates the received signals when the arrival determination unit determines that the desired signal has arrived.

Abstract: A wireless communication apparatus includes a channel-usage selection unit to select one frequency channel for each time slot from a plurality of predetermined candidate frequency channels, and a wireless communication unit to perform wireless communication by using the frequency channel selected by the channel-usage selection unit. The channel-usage selection unit selects a frequency channel that is different from a frequency channel to be used in a same time slot by an adjacent cell located at a cell interval, equal to or smaller than the predetermined first number of cells, from a cell used for the wireless communication, and allows the frequency channel selected to overlap with the frequency channel to be used in the same time slot by a remote cell located at a cell interval, greater than the first number of cells and equal to or smaller than the number of the candidate frequency channels, from a cell used for the wireless communication.

Abstract: A transmitter according to the present invention includes: a mapping unit that generates modulation symbols by modulating a transmission bit sequence; a DSTBC coding unit that generates coded symbols by performing differential space-time block coding on the modulation symbols; a code conversion unit that performs, on the coded symbols, a conversion process selected from among a plurality of conversion processes; and an antenna that transmits the coded symbols after the conversion process.

Abstract: In a wireless communication system, SINR data are obtained from power measurements data, as follows: gathering first power measurements data of total power received during communications; gathering second power measurements data of in-transmission interference power; computing third power measurements data of useful power, from the first and second power measurements data; gathering fourth power measurements data of out-transmission interference power; merging the second and fourth power measurements data so as to form a set of fifth interference power data; computing a first characteristic function from the third power measurements data, and computing a second characteristic function from the fifth power measurements data; building a third characteristic function relating to the SINR data related to the transmission channel, by performing a term-by-term product of the first and second characteristic functions; computing a probability mass function from the third characteristic function.

Abstract: A radio wave monitoring apparatus includes a communication quality evaluation unit which notifies degradation of communication quality of wireless communication when a non-transmission probability exceeds a threshold, the non-transmission probability having been calculated based on measurement results of communication quality of wireless communication between an on-board station mounted on a train traveling on a track and ground stations installed along the track, and a condition by which it is determined that transmission information is unreachable in the wireless communication.

Abstract: A wireless receiving device includes a signal measurement unit that measures received signals; a weighting factor generation unit that generates weighting factors each for suppression of the received signals, based on measurement results of the received signals; interference suppression units that each perform, in a parallel manner, interference suppression processing on the received signals, using one of the weighting factors, the one weighting factor used by one of the interference suppression units being different from weighting factors used by other interference suppression units, the plurality of weighting factors being generated at different points of time; arrival detection units that are connected in one-to-one to the interference suppression units, the arrival detection units each detecting arrival of a desired signal, using received signals that have been subjected to the interference suppression processing in the corresponding interference suppression unit connected thereto; an arrival determinatio

Abstract: In a satellite communication system to relay communication between a terminal and a gateway installed on the ground through a satellite repeater, the satellite repeater forms a user link beam for communicating with the terminal and a feeder link beam for communicating with the gateway in a same area, and changes frequency or polarization association with respect to each of the user link beam and the feeder link beam, based on a traffic situation. Thus, a capacity that can be communicated by the beam may be changed after satellite launching.

Abstract: A radio wave monitoring apparatus includes a communication quality evaluation unit which notifies degradation of communication quality of wireless communication when a non-transmission probability exceeds a threshold, the non-transmission probability having been calculated based on measurement results of communication quality of wireless communication between an on-board station mounted on a train traveling on a track and ground stations installed along the track, and a condition by which it is determined that transmission information is unreachable in the wireless communication.