Abstract: Radio communication system includes radio transmitter containing unit dividing transmission data into first-code blocks each having N-bit data, unit adding error detection codes to first-code blocks, unit assigning first-code blocks to second-code blocks each including M carriers each having L symbols, and unit transmitting second-code blocks, and radio receiver containing unit receiving second-code blocks, unit converting second-code blocks into first-code blocks, based on values of M and L, unit subjecting first-coded blocks to error correction decoding, unit detecting error of code block of first-code blocks subjected to error correction decoding, unit generating retransmission-request signal for requesting retransmission of code block including error, if error is detected, and unit transmitting retransmission-request signal.

Abstract: A modulator includes a first input configured to input a first bit string; a first modulating device configured to modulate the inputted first bit string at a first bit rate; a second input configured to input a second bit string; a second modulating device configured to modulate the inputted second bit string at a second bit rate which is lower than the first bit rate; and an output configured to output a modulated signal including the modulated first bit string and the modulated second bit string.

Abstract: There is provided with there is provided with a wireless communication method using a frequency hopping scheme, which performs wireless communication with a different wireless communication apparatus by using a plurality of frequency bands, including: measuring interference quantities showing strength of interference signals in respective frequency bands; selecting a hopping pattern from a plurality of hopping patterns each having hopping densities set for the respective frequency bands on the basis of the interference quantities in the respective frequency bands, the hopping densities being the number of times that transmission is performed per unit time in the respective frequency bands; notifying the different wireless communication apparatus of the selected hopping pattern; and communicating with the different wireless communication apparatus by using the selected hopping patter.

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: A transfer control device is arranged between a bus and a bus interface. The transfer control device includes a bus connecting unit that is connected to plural signal lines of the bus, an interface connecting unit that is connected to plural signal lines of the bus interface, and a connection control unit that connects, when a defective signal line exists in the plural signal lines of the bus, a signal line corresponding to the defective signal line out of the plural signal lines of the bus interface and a signal line other than the defective signal line out of the plural signal lines of the bus.

Abstract: Radio communication system includes radio transmitter including adding unit adding parity bit for error detection to data, spreading unit spreading, in time-and-frequency direction, data with parity bit, based on spreading pattern, transmission unit transmitting spread data, and reception unit receiving retransmission-request signal, wherein in response to retransmission-request signal, spreading unit spreads to-be-retransmitted data with parity bit, based on varied spreading pattern being varied according to spreading rate in time direction and spreading rate in frequency direction, and transmission unit transmits spread to-be-retransmitted data, and radio receiver including reception unit receiving transmitted spread data, de-spreading unit de-spreading received spread data, based on spreading pattern, error detection unit detecting error of de-spread data, based on parity bit, and transmission unit transmitting retransmission-request signal requesting retransmission of data if error is detected in de-sprea

Abstract: A radio communication terminal includes a detection unit configured to detect a plurality of usable frequencies of a frequency range, in which the radio communication terminal plans to transmit, at least depending on whether or not a power of a first received signal is greater than a first threshold, a selection unit configured to select, when a first frequency band from f0+f1 to f0+f1+?f1 (f1 is a first frequency, and ?f1 is a first bandwidth) and a second frequency band from f0?f1??f1 to f0?f1 are simultaneously usable with respect to a center frequency f0 of a utilizing frequency range including the usable frequencies, the first frequency band and the second frequency band as a pair of utilizing frequency bands, and a transmission unit configured to transmit different signals in the pair of utilizing frequency bands.

Abstract: A radio communication system which includes a base station apparatus and terminal apparatuses and performs TDD two-way communications using an OFDM signal including subcarriers in a downstream communication from the base station apparatus to each terminal apparatus, and an FH signal having the same frequency band as that of the subcarriers in an upstream communication from the each terminal apparatus to the base station apparatus, the each terminal apparatus estimates transmission channel characteristics of the subcarriers based on the OFDM signal received, transmits an estimation result of the estimation unit to the base station apparatus, and the base station apparatus assigns, to the each terminal apparatus, at least one of subcarriers to be used in the downstream communication of the subcarriers and a hopping pattern to be used in the upstream communication, based on the estimation result transmitted from the each terminal apparatus.

Abstract: Radio communication apparatus for receiving OFDM signal from base station and transmitting FH signal to base station, using sub-channels, base station comparing hopping pattern information items indicating hopping patterns from radio communication apparatuses including radio communication apparatus, and generating collision information when hopping patterns include colliding hopping patterns, includes estimation unit configured to estimate channel response values of sub-channels based on OFDM signal, selector which selects, from sub-channels, several sub-channels which have higher channel response values than a value, each of channel response values being expressed by power level, signal-to-noise power ratio, or signal-to-interference ratio, determination unit configured to determine hopping pattern from selected sub-channels, transmitter which transmits, to base station, hopping pattern information item indicating determined hopping pattern, receiver which receives collision information from base station, an

Abstract: The present invention provides a method of improving the performance of a CDMA based wireless network, such as a 3G cellular network for example. Interference cancellation is effectively performed earlier by using the channel request such as a reservation packet from a mobile terminal to estimate interference from that mobile on existing mobile users and interference on the mobile from existing mobile users, by determining the relative transmission timing of the new mobiles channel request compared with the transmission timings of the existing mobiles. The base station determine the cross-correlation between the codes already assigned to the existing users and the code to be allocated to the new user in order to determine an interference measure. This interference can then be cancelled from the new mobile when its data packets are received.

Abstract: A radio communication apparatus connected to a device including a digital signal processing unit generating a clock signal, the apparatus includes an acquisition unit acquiring frequency information concerning the clock signal from the digital signal processing unit, a first measurement unit measuring a signal power in a first frequency band, a comparison unit comparing the signal power with a threshold, a first selection unit selecting, from the first frequency band, a second frequency band necessary for data communication, a bandwidth of the first frequency band whose signal power is lower than the threshold being more than a bandwidth of the second frequency band, a second selection unit selecting an optimum communication scheme from a plurality of communication schemes of the data communication according to the frequency information, and a communication unit using the optimum communication scheme to perform the data communication in the second frequency band.

Abstract: A communication apparatus, includes unit extracting a reception key feature of a temporal change in received power in each frequency band contained in a received signal, unit storing, in correspondence with one another, a system name of a system which uses the frequency band, event information indicating that a communication apparatus belonging to the system starts or stops transmission, and a transmission key feature of a temporal waveform change shape of a transmission signal from a communication apparatus belonging to the system, a transmission key feature corresponding to the event information, unit determining whether there is any transmission key feature matching the reception key feature, by comparing the reception key feature with the transmission key feature, and unit selecting, when the determination unit determines that there is a matched transmission key feature, the event information and the system name which correspond to the transmission key feature from the storage unit.

Abstract: A radio communication terminal includes a first transmitting unit configured to transmit a beacon, a second transmitting unit configured to transmit a first notifying signal which includes information of a frequency of the beacon and a transmission timing of the beacon, a measuring unit configured to measure a reception power of a signal transmitted by each of a plurality of slave radio communication terminals, a selecting unit configured to select a notifying radio communication terminal, which is to transmit a second notifying signal, from the slave radio communication terminals based on the reception power, the second notifying signal including the same information of the frequency of the beacon and the transmission timing of the beacon as the information included in the first notifying signal, and a third transmitting unit configured to transmit, to the notifying radio communication terminal, notifying instruction information including an instruction to transmit the second notifying signal.

Abstract: A radio communication apparatus includes a first detection unit configured to detect a first signal in a first carrier sense period contained in a pre assigned reception slot, a relaying unit configured to relay the detected first signal, a second detection unit configured to detect a second signal in a second carrier sense period contained in a pre assigned transmission slot, and a stopping unit configured to stop transmission in the transmission slot when the second detection unit detects the second signal.

Abstract: A communication apparatus includes unit measuring a first interference feature quantity indicating a state of an interference signal in a transmission frequency band (TFB), unit determining from the first interference feature quantity whether the interference signal exists in the TFB, unit acquiring, after measurement of the first interference feature quantity, a transmission channel from a second interference feature quantity measured by the measuring unit, the transmission channel corresponding to at least one of a frequency orthogonal to the interference signal, a time orthogonal to the interference signal, a space orthogonal to the interference signal, and a spreading code orthogonal to the interference signal, and unit performing a first transmission using the TFB when it is determined that no interference signal exists in the TFB, and to perform a second transmission using the transmission channel when it is determined that the interference signal exists in the TFB.

Abstract: A cognitive radio system includes: a state detecting device that scans a frequency band allocated to another radio system than the cognitive radio system to detect a first use-state of the frequency band; a first server including a first gathering unit that receives first information relating to the first use-state and a second gathering unit; a second server that stores a second use-state of the frequency band allocated to the other radio system, the second server configured to provide second information relating to the second use-state to the second gathering unit; and a notifying unit that notifies a terminal device in the cognitive radio system of information of an available channel based on the first information and the second information.

Abstract: A terminal station radio communication device belongs to a second radio communication system which shares a frequency channel with a first radio communication system in which a radio terminal station communicates with a radio base station in a predetermined time period using a predetermined frequency channel. The terminal station radio communication device includes: a transmission power determining unit which sets up signal transmission power, the signal transmission power being usable for communications between radio communication devices belonging to the second radio communication system, and being determined such that reception power at the radio base station is below a predetermined threshold; a synchronizer enabling the radio terminal station to obtain timing information to start signal transmission; and a signal transmitter starting transmitting the signal at the timing represented by the timing information and terminating the signal transmission within a predetermined time period.

Abstract: There is provided with a communication control method including: measuring signal quality of signals which reach a terminal device from base stations; determining one or more base station to communicate with the terminal device based on the signal quality, and transmitting an instruction signal to instruct to communicate between determined base stations and the terminal device on a time-division scheme to the base stations and transmitting an instruction signal to instruct stoppage of communication to a base station determined not to communicate with the terminal, when a change of the base stations to communicate with the terminal device occurs and the number of base stations is two or more after the change.

Abstract: There is provided with there is provided with a wireless communication method using a frequency hopping scheme, which performs wireless communication with a different wireless communication apparatus by using a plurality of frequency bands, including: measuring interference quantities showing strength of interference signals in respective frequency bands; selecting a hopping pattern from a plurality of hopping patterns each having hopping densities set for the respective frequency bands on the basis of the interference quantities in the respective frequency bands, the hopping densities being the number of times that transmission is performed per unit time in the respective frequency bands; notifying the different wireless communication apparatus of the selected hopping pattern; and communicating with the different wireless communication apparatus by using the selected hopping patter.

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.