Abstract: There is provided a wireless communication device in a wireless communication system including one or more communication devices installed on the ground and a moving wireless communication device, the wireless communication device including: an activation signal generation unit that generates an activation signal for activating the one or more communication devices; a distribution unit that distributes the activation signal generated by the activation signal generation unit; one or more frequency change application units that apply a frequency change to the activation signal distributed by the distribution unit; and a transmission unit that transmits an activation signal to which a frequency change is applied to the one or more frequency change application units.

Abstract: A receiving apparatus includes: M receivers configured to receive signals based on sound waves propagating in water; M FIR filters configured to perform waveform operation on the signals received by the receivers; a combiner configured to combine output signals of the M FIR filters; and a filter coefficient calculation portion configured to calculate a tap coefficient of the M FIR filters so as to reduce an error of the output signals combined by the combiner. The M FIR filters have a tap length that is shorter than a delay spread that is a possible range between a time of arrival of a direct wave and a time of arrival of a delayed wave of the sound waves.

Abstract: A station installation designing assistance device that divides a service providing area into a plurality of areas, and performs station installation designing for the plurality of areas in parallel, the station installation designing assistance device including: an area dividing unit that divides an entirety of the service providing area into a plurality of areas that are each composed of a predetermined number of small areas; a small area specifying unit that specifies a small area number that identifies a small area in each of the areas, where the same number is given to the small area in each of the areas; and a station installation location selecting unit that selects, for each of the plurality of areas, a plurality of station installation locations from among station installation location candidates that are present in the small area specified by the small area specifying unit.

Abstract: A radio transmission apparatus includes a communication distance measurement unit configured to measure a distance between a plurality of transmission antennas and a plurality of reception antennas, a selection unit configured to select a modulation scheme common to all frequency channels, the modulation scheme satisfying an average value of index values for each of the frequency channels according to a measured distance and satisfying a predetermined desired bit error rate, a transmission signal generation unit configured to separate transmission data, modulate each item of the separated transmission data by the selected common modulation scheme, and output the transmission signals multiplexed by the number of multiplexing indicating the number of the plurality of transmission antennas to be used. A radio reception apparatus includes a demodulation unit configured to demodulate a reception signal by a demodulation scheme corresponding to the modulation scheme to generate reception data.

Abstract: A communication quality calculation unit (11) of a base station placement design device (1) calculates communication quality of each terminal in a case where a base station is installed at a base station placement candidate location for a plurality of base station placement candidate locations. An aggregation unit (12) aggregate the number of terminals whose communication quality calculated by the communication quality calculation unit (11) is equal to or greater than a threshold value for each of the plurality of base station placement candidate locations. A base station placement location selection unit (13) selects a base station placement location from among the plurality of base station placement candidate locations, based on the number of terminals aggregated by the aggregation unit (12) for each of the plurality of base station placement candidate locations.

Abstract: A communication control device that transmits a packet to be transmitted to a terminal to a base station that performs wireless communication with the terminal, includes: a terminal classification unit that classifies, on the basis of a magnitude of radio wave interference from a base station different from a neighboring base station, a plurality of the terminals into a first terminal set and a second terminal set that is relatively larger in the magnitude of radio wave interference than the first terminal set; and a transmission unit that transmits, in a case where packets destinations of which are terminals belonging to the first terminal set are to be transmitted to respective neighboring base stations of the terminals, the packets at the same timing and transmits, in a case where packets destinations of which are terminals belonging to the second terminal set are to be transmitted to respective neighboring base stations of the terminals, the packets at timings different from each other.

Abstract: A station installation designing assistance device that divides a service providing area into a plurality of areas, and performs station installation designing for the plurality of areas in parallel, the station installation designing assistance device including: an area dividing unit that divides an entirety of the service providing area into the plurality of areas; a station installation priority determining unit that determines, for each of the plurality of areas, station installation priorities of station installation location candidates that are present in the area; and a station installation priority adjusting unit that adjusts the station installation priorities determined by the station installation priority determining unit, based on a degree of overlap of cells formed as a result of base stations being installed in station installation location candidates in the areas, respectively.

Abstract: A receiver including a plurality of wave receivers that receive signals arriving from a predetermined direction, a plurality of detection units that is connected to at least some of the plurality of wave receivers and detect arrival times of signals received by a connected wave receivers, and a plurality of adjustment units that adjust a deviation between arrival times of the plurality of wave receivers based on arrival times or arrival directions of the plurality of detected signals.

Abstract: According to an aspect of the present invention, there is provided a communication apparatus including: a synchronizer configured to perform synchronization processing according to a Doppler shift on a reception signal; and an equalizer configured to perform equalization processing on a reception signal on which the synchronization processing has been performed, in which the synchronizer includes a correlator configured to output a correlation between a reception signal and a known preamble sequence and a correlation between the reception signal and a known postamble sequence, a slide correlator configured to output a sliding correlation based on an output of the correlator, and a Doppler estimator configured to estimate a Doppler shift based on the sliding correlation of the slide correlator

Abstract: A communication method determination apparatus includes a comparison unit and an instruction unit. The comparison unit obtains a bit string of a portion of a physical header for synchronization from a wireless frame that includes the physical header for synchronization in which information for synchronization in a physical layer is set and a physical data portion in which data of a higher-level layer than the physical layer is set, and compares the obtained bit string with a bit string pattern specific to a communication method targeted for determination. The instruction unit performs communication method determination processing for determining whether or not the communication method targeted for determination is used for the wireless frame, based on a result of comparison.

Abstract: A signal acquisition unit acquires a reception signal received by a reception device from a transmission device that moves relative to the reception device. A compensation unit compensates for a Doppler shift of the reception signal on the basis of a possibility of a change amount of the Doppler shift. A search unit changes a value of a possibility of the change amount of the Doppler shift in a case where a bandwidth having a power equal to or greater than a predetermined threshold in frequency components of the reception signal after the compensation is larger than a predetermined value.

Abstract: A receiving apparatus includes: M receivers configured to receive signals based on sound waves propagating in water; M FIR filters configured to perform waveform operation on the signals received by the receivers; a combiner configured to combine output signals of the M FIR filters; and a filter coefficient calculation portion configured to calculate a tap coefficient of the M FIR filters so as to reduce an error of the output signals combined by the combiner. The M FIR filters have a tap length that is shorter than a delay spread that is a possible range between a time of arrival of a direct wave and a time of arrival of a delayed wave of the sound waves.

Abstract: An arrival rate estimation device includes an average received power calculation unit that calculates an average received power for each mesh that constitutes an area, with respect to each of a plurality of base stations and each of a plurality of antennas included in each of the base stations and an arrival rate estimation unit that calculates a communication arrival rate by substituting the average received power into a cumulative distribution function of an instantaneous received power value, and based on the calculated communication arrival rate, calculates a communication arrival rate while giving consideration to a site diversity effect and an antenna diversity effect, the cumulative distribution function being obtained from a probability density function of an amplitude that instantaneously changes due to Rayleigh fading.

Abstract: A transmission data controller determines a frequency bandwidth according to a relay apparatus position, the frequency bandwidth being used for a first signal transmitted from a first communication apparatus, on the basis of information regarding the number of first communication apparatuses with which a relay apparatus communicates at the relay apparatus position. The transmission data controller transmits band information indicating a frequency band selected from radio frequency bands that can be used for the first signal on the basis of the determined frequency bandwidth to the first communication apparatus. The first communication apparatus transmits the first signal having a frequency included in the frequency band indicated by the band information. The relay apparatus acquires waveform data of the first signal transmitted by the first communication apparatus, and transmits the acquired waveform data to a second communication apparatus by a second signal.

Abstract: Exemplary communication system 1 includes game devices 10, communication terminals 20, and game support server 30. Game devices 10 enable users to perform a multi-play activity. Each of communication terminals 20 runs an application associated with corresponding game device 10. Game support server 30 divides communication terminals 20 into separate communication groups in accordance with a situation of the multi-play activity performed by game devices 10 so that communication terminals 20 belonging to a same communication group can communicate with each other.

Abstract: An underwater acoustic communication system includes a transmission device including N transmitters, and a reception device. The reception device includes M (M is an integer of two or more) receivers configured to receive M reception signal sequences corresponding to N transmission signal sequences transmitted from the N transmitters through sound waves, a beam former configured to suppress multipath waves other than direct waves of the M received reception signal sequences and to generate L (L is an integer of two or more) signal sequences from the M reception signal sequences, and a signal estimation unit configured to estimate the N transmission signal sequences based on the L generated signal sequences.

Abstract: A communication device includes an antenna, a support portion, an actuator, a floating body, a sensor, and a control device. The antenna has a rod-shaped element. The instruction unit supports the antenna rotatably about a rotation axis orthogonal to an extending direction of the element. The actuator rotates the antenna about the rotation axis. The floating body supports the support portion and floats on water. The sensor measures a physical quantity related to inclination of the support portion. The control device includes a measurement value acquisition unit and a rotation control unit. The measurement value acquisition unit acquires a measurement value of the sensor. The rotation control unit drives the actuator on the basis of the measurement value to match a direction in which a change in the inclination is smallest with an extending direction of the antenna.

Abstract: A moving relay apparatus includes a first signal receiver, a second signal transmitter, and a transmission data controller. The first signal receiver receives a wireless first signal transmitted by the first communication apparatus by a reception antenna, and acquires waveform data of the first signal received by the reception antenna. A second signal transmitter transmits the waveform data acquired by the first signal receiver to the second communication apparatus by a second signal. A transmission data controller controls a data amount of the waveform data generated by the first signal receiver on the basis of information regarding communication quality between the relay apparatus and the first communication apparatus at a relay apparatus position where the first signal has been received.

Abstract: The receiving apparatus includes a signal receiver, a second signal reception processor, a first signal reception processor, and a controller. The signal receiver receives the second signal indicating the reception time and the waveform data indicating the waveform of the first signal received from the transmission apparatus by each of the plurality of receiving antennas of the relay apparatus. The second signal reception processor performs reception processing of the second signal to acquire waveform data. The first signal reception processor performs reception processing of the first signal indicated by the waveform data to acquire data set to the first signal by the transmission apparatus. The controller calculates a generation time and a generation position of the interference signal with respect to the first signal on the basis of the observation result of the radio signal in the observation apparatus.

Abstract: A wireless communication apparatus includes: a transmission control unit that determines an earlier transmission timing as an elevation angle of a relay apparatus when viewed from the own wireless communication apparatus is larger; and a transmission unit that transmits a wireless signal to the relay apparatus at the transmission timing. The wireless communication apparatus may further include a reception unit that acquires an upper limit value. The transmission control unit may derive a subtraction value, which is a variable value to be used for subtraction, as a larger value as the elevation angle is larger, may subtract the subtraction value from a backoff counter value which is derived based on the upper limit value and is equal to or larger than 0, and may determine, as the transmission timing, a timing at which the backoff counter value becomes equal to or smaller than 0.