Abstract: A wireless control apparatus controls beamforming performed by a wireless base station apparatus that provides a communication service to a service area which includes a plurality of spots to be irradiated with a beam including a terminal search beam and a communication beam that are not used simultaneously for irradiation, and is irradiated with a plurality of the beams and is not simultaneously covered by the plurality of beams, and the apparatus includes: an arrival direction estimation unit that estimates an arrival direction of a wireless signal transmitted by a terminal communicating with a wireless base station; and a control unit that determines whether there is an active terminal in the spots on the basis of the arrival direction estimated by the arrival direction estimation unit, and, when it is determined that there is no active terminal, controls beamforming performed by the wireless base station apparatus to decrease a frequency of the terminal search beam with which one or more of the spots dete

Abstract: Provided is a beam transmission/reception method, which is executed in a wireless communication system in which a terminal and a base station use a beam to communicate to and from each other. The method includes a step of grouping, by the base station, when the base station is to receive a random access channel signal transmitted as a connection request from the terminal, a plurality of beam directions by combining a main beam direction, which is determined as suitable for reception of the random access channel signal, with one or more beam directions adjacent to the main beam direction, and of receiving the random access channel signal with use of the grouped plurality of beam directions.

Abstract: A wireless control apparatus controls beamforming performed by a wireless base station apparatus that provides a communication service to a service area which includes a plurality of spots to be irradiated with a beam including a terminal search beam and a communication beam that are not used simultaneously for irradiation, and is irradiated with a plurality of the beams and is not simultaneously covered by the plurality of beams, and the apparatus includes: an arrival direction estimation unit that estimates an arrival direction of a wireless signal transmitted by a terminal communicating with a wireless base station; and a control unit that determines whether there is an active terminal in the spots on the basis of the arrival direction estimated by the arrival direction estimation unit, and, when it is determined that there is no active terminal, controls beamforming performed by the wireless base station apparatus to decrease a frequency of the terminal search beam with which one or more of the spots dete

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 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 base station apparatus that communicates with a plurality of terminals via spatial multiplexing includes: an active array antenna to transmit a first transmit signal; sector antennas to transmit second transmit signals; and a digital signal processor that generates the first transmit signal that is transmitted from the active array antenna and generates the second transmit signals that are transmitted from the sector antennas, the second transmit signals being transmit signals for eliminating interference between the terminals generated by the first transmit signal.

Abstract: A wireless base station apparatus that communicates with a plurality of terminals via spatial multiplexing includes: an active array antenna to transmit a first transmit signal; sector antennas to transmit second transmit signals; and a digital signal processor that generates the first transmit signal that is transmitted from the active array antenna and generates the second transmit signals that are transmitted from the sector antennas, the second transmit signals being transmit signals for eliminating interference between the terminals generated by the first transmit signal.

Abstract: A transmitter includes: a null symbol map unit to determine a null symbol arrangement pattern by combining different unit patterns determining positions of data symbols and null symbols; a subcarrier map unit to assign, in a two-dimensional space defined by a plurality of subcarriers for use in multicarrier transmission and a time series represented in units of time determined in accordance with a single symbol, transmission data to positions of data symbols of the respective subcarriers determined in accordance with the null symbol arrangement pattern; a modulator to generate the data symbols by modulating the assigned transmission data, assign null symbols having a power of 0 to positions of null symbols of the respective subcarriers determined in accordance with the null symbol arrangement pattern, and generate transmission symbols of the respective subcarriers; and a baseband section to output a baseband signal based on the transmission symbols.

Abstract: Provided is a beam transmission/reception method, which is executed in a wireless communication system in which a terminal and a base station use a beam to communicate to and from each other. The method includes a step of grouping, by the base station, when the base station is to receive a random access channel signal transmitted as a connection request from the terminal, a plurality of beam directions by combining a main beam direction, which is determined as suitable for reception of the random access channel signal, with one or more beam directions adjacent to the main beam direction, and of receiving the random access channel signal with use of the grouped plurality of beam directions.

Abstract: A transmitter includes: a null symbol map unit to determine a null symbol arrangement pattern by combining different unit patterns determining positions of data symbols and null symbols; a subcarrier map unit to assign, in a two-dimensional space defined by a plurality of subcarriers for use in multicarrier transmission and a time series represented in units of time determined in accordance with a single symbol, transmission data to positions of data symbols of the respective subcarriers determined in accordance with the null symbol arrangement pattern; a modulator to generate the data symbols by modulating the assigned transmission data, assign null symbols having a power of 0 to positions of null symbols of the respective subcarriers determined in accordance with the null symbol arrangement pattern, and generate transmission symbols of the respective subcarriers; and a baseband section to output a baseband signal based on the transmission symbols.

Abstract: A radio communication apparatus that performs radio communication according to a multicarrier scheme includes: a transmitting unit including a null inserting unit that dispersedly arranges null symbols in a two-dimensional space of time and frequency in radio data, and a differential modulating unit that performs differential modulation on a data symbol part other than the null symbols; and a receiving unit including an interference measuring unit that measures interference power for a data symbol that is a measurement target by using a null symbol adjacent to the data symbol in the two-dimensional space of time and frequency, and a delay detecting unit that performs weighting on each data symbol according to the interference power measured for each data symbol and that performs delay detection between data symbols.

Abstract: A receiving device according to the present invention is a receiver for receiving a signal including null symbols. The receiver includes a null extraction unit for extracting the null symbols from the received signal, a power calculation unit for calculating a power of each null symbol extracted by the null extraction unit, a two-dimensional filter unit for performing a plurality of kinds of filtering for the powers of the respective null symbols calculated by the power calculation unit and obtaining a plurality of kinds of average power values, and a normalizing unit for normalizing a data symbol included in the received signal based on a value obtained by performing nonlinear processing to the average power values obtained by the two-dimensional filter unit.

Abstract: A receiving device according to the present invention is a receiver for receiving a signal including null symbols. The receiver includes a null extraction unit for extracting the null symbols from the received signal, a power calculation unit for calculating a power of each null symbol extracted by the null extraction unit, a two-dimensional filter unit for performing a plurality of kinds of filtering for the powers of the respective null symbols calculated by the power calculation unit and obtaining a plurality of kinds of average power values, and a normalizing unit for normalizing a data symbol included in the received signal based on a value obtained by performing nonlinear processing to the average power values obtained by the two-dimensional filter unit.

Abstract: A radio communication apparatus that performs radio communication according to a multicarrier scheme includes: a transmitting unit including a null inserting unit that dispersedly arranges null symbols in a two-dimensional space of time and frequency in radio data, and a differential modulating unit that performs differential modulation on a data symbol part other than the null symbols; and a receiving unit including an interference measuring unit that measures interference power for a data symbol that is a measurement target by using a null symbol adjacent to the data symbol in the two-dimensional space of time and frequency, and a delay detecting unit that performs weighting on each data symbol according to the interference power measured for each data symbol and that performs delay detection between data symbols.

Abstract: A calibration method according to the present invention includes a step of first channel estimating for transmitting a pilot signal from a first antenna and receiving the pilot signal at a second antenna different from the first antenna to calculate a first channel estimation value; a step of second channel estimating for transmitting a plot signal from the second antenna and receiving the pilot signal at the first antenna to calculate a second channel estimation value; and a step of correction coefficient calculating for calculating, by using the first and second channel estimation values, a correction coefficient.

Abstract: An auto frequency control method of this invention has a first step of a base station BS detecting a frequency deviation ?fBS of an uplink signal transmitted from a mobile station MS, a second step of the base station BS transmitting an instructing amount of increase or decrease fcont of the transmission frequency fMS of the uplink signal to the mobile station MS on the basis of the frequency deviation ?fBS of the uplink signal, and a third step of the mobile station MS shifting the transmission frequency fMS of the uplink signal according to the instructing amount of increase or decrease fcont transmitted from the base station BS.

Abstract: A signal generation/noise extraction unit that includes an analog-to-digital converter, a switch, a filter, a subtracter, an oscillator, a multiplier, and a switch generates a down-sampled signal at a frequency at which aliasing occurs, from an input signal, and extracts an aliasing noise component included in the down-sampled signal. A dispreading unit includes a (1/n)× over-sampling matched filter, a 1× over-sampling matched filter conducts dispreading processings to the down-sampled signal and the aliasing noise component. A noise canceling unit includes filters, a multiplier, an adder, and a switch combines two dispreading results, and cancels the aliasing noise component.

Abstract: A matched filter takes a correlation between a plurality of multiplexed spread spectrum signals and a spreading code. A cyclic integrator integrates a correlation waveform, associated integration outputs with phases, and sets up a maximum detection when an integration value corresponding to a predetermined phase is detected as a maximum. A correlation peak canceller regards an integration value of a phase having the maximum detection flag as a maximum of the correlation waveform of the spreading code, generates a replica signal, and eliminates the replica signal from an output of the integration. A maximum detection unit detects a maximum in a predetermined integration period and a phase corresponding to the maximum from the output of the integration after eliminating the replica signal.

Abstract: The spread spectrum reception apparatus is provided with a RAKE-combination path timing detector which detects a first path using a delay profile produced with a correlation electric power value with improved signal-to-electric power ration by performing cyclic integration of electric power, detects a second path based on the corrected delay profile by correcting a correlation electric power value of the delay profile using a correction coefficient corresponding to a deviation of delay time of the first path signal. A correction coefficient storing unit stores correction coefficient pre-calculated giving consideration to time correlation of interference and thermal noise.

Abstract: A receiver of this invention includes a signal generation and noise extraction unit (A/D converter 1, a switch 2, a filter 3, a subtracter 4, an oscillator 5, a multiplier 6, and a switch 7) that generates a down-sampled signal at a frequency at which aliasing occurs, from an input signal, and that extracts an aliasing noise component included in the down-sampled signal; a despreading unit (a 1/n times over-sampling matched filter 8, a one time over-sampling matched filter 11) that individually conducts despreading processings to the down-sampled signal and the aliasing noise component; and a noise cancellation unit (filters 3 and 9, a multiplier 10, an adder 12, and a switch 13) that combines the two despreading results, and that thereby cancels the aliasing noise component.