Abstract: According to one embodiment, An electronic apparatus that is capable to communicate with a wireless apparatus includes: a receiver to receive a first signal including first information in which the wireless apparatus is in a synchronous state, or a second signal including second information in which the wireless apparatus is in an asynchronous state; and a processor configured to switch the electronic apparatus from an asynchronous state to a synchronous state in response to reception of the first signal or reception of one or more of the second signals.

Abstract: According to one embodiment, an electronic apparatus includes processing circuitry. The processing circuitry estimates a first AoA of an arrival wave corresponding to a received signal from a receiving element array. The processing circuitry determines whether the estimated first AoA is an outlier or not. The processing circuitry outputs the first AoA as a second AoA, when the first AoA is not to be an outlier. The processing circuitry acquires one or more main-lobe angles assuming that the first AoA is a side-lobe angle of the receiving element array, when the first AoA is to be an outlier. The processing circuitry determines whether the main-lobe angle is an outlier or not. The processing circuitry outputs the main-lobe angle as the second AoA, when the main-lobe angle is not to be an outlier.

Abstract: According to one embodiment, An electronic apparatus that is capable to communicate with a wireless apparatus includes: a receiver to receive a first signal including first information in which the wireless apparatus is in a synchronous state, or a second signal including second information in which the wireless apparatus is in an asynchronous state; and a processor configured to switch the electronic apparatus from an asynchronous state to a synchronous state in response to reception of the first signalor reception of one or more of the second signals.

Abstract: According to one embodiment, a wireless receiver includes reception circuitry and processor circuitry. The reception circuitry receives a radio wave from a radio wave emitter. The processor circuitry estimates a parameter of a ratio of a first received power of a line-of-sight component in the radio wave to a second received power of the radio wave, estimate the first received power based on the parameter and a value of the second received power; and calculate a distance to the radio wave emitter, based on the first received power.

Abstract: According to one embodiment, an electronic apparatus includes processing circuitry. The processing circuitry estimates a first AoA of an arrival wave corresponding to a received signal from a receiving element array. The processing circuitry determines whether the estimated first AoA is an outlier or not. The processing circuitry outputs the first AoA as a second AoA, when the first AoA is not to be an outlier. The processing circuitry acquires one or more main-lobe angles assuming that the first AoA is a side-lobe angle of the receiving element array, when the first AoA is to be an outlier. The processing circuitry determines whether the main-lobe angle is an outlier or not. The processing circuitry outputs the main-lobe angle as the second AoA, when the main-lobe angle is not to be an outlier.

Abstract: A wireless receiver includes an antenna array and processing circuitry. The antenna array receives radio waves from a radio wave radiator to output received signals. The processing circuitry calculates similarity indices based on (1) a first eigenvector corresponding to a largest eigenvalue of a covariance matrix of each of the received signals, and (2) a degree of similarity between the first eigenvector and a steering vector of a single wave, estimates angles of arrival of the received signals, and determines an output angle of arrival from the estimated angles of arrival of the received signals.

Abstract: A wireless receiver includes an antenna array and processing circuitry. The antenna array receives radio waves from a radio wave radiator to output received signals. The processing circuitry calculates similarity indices based on (1) a first eigenvector corresponding to a largest eigenvalue of a covariance matrix of each of the received signals, and (2) a degree of similarity between the first eigenvector and a steering vector of a single wave, estimates angles of arrival of the received signals, and determines an output angle of arrival from the estimated angles of arrival of the received signals.

Abstract: According to one embodiment, a wireless receiver includes reception circuitry and processor circuitry. The reception circuitry receives a radio wave from a radio wave emitter. The processor circuitry estimates a parameter of a ratio of a first received power of a line-of-sight component in the radio wave to a second received power of the radio wave, estimate the first received power based on the parameter and a value of the second received power; and calculate a distance to the radio wave emitter, based on the first received power.

Abstract: A protection path reservation method which reserves protection paths to avoid a node failure for each transmission path on a network formed of a plurality of nodes, comprising assuming the nodes as an imaginary failure node in turn in a condition in which the node failure is not present in the network, and selecting N neighbor nodes connected to the imaginary failure node through N links, wherein the imaginary failure nodes sequentially transmit protection path reservation request messages to neighbor nodes, and the nodes which have received the protection path reservation request messages sequentially, one by one, reserve N?1 protection paths starting from the nodes.

Abstract: In a method for communication, first and second signals for timing synchronization are generated. Frequencies of the first and second signals are converted to other frequencies to obtain a first and second RF signals, which have a specific frequency gap therebetween. The first and second RF signals are combined to obtain a transmission signal, and the transmission signal is transmitted. When the transmission signal is received as a received signal, the frequency of the received signal is shifted by the specific frequency gap to obtain a converted signal. A complex conjugation of the converted signal calculated to obtain a complex conjugation signal. The received signal and the complex conjugation signal are multiplied to obtain a multiplication signal to calculate cross-correlation between a product of the first and second signals and the multiplication signal. A peak of the cross-correlation is detected to set a base time for timing synchronization.

Abstract: A radio communication apparatus includes a first acquisition unit configured to acquire a first frequency use status of a first frequency band having a first center frequency, a second acquisition unit configured to acquire a second frequency use status of a second frequency band having a second center frequency which is a value M/N times (M and N are natural numbers, and M?N) of the first center frequency, and a decision unit configured to determine whether a harmonic is detected in the first frequency band using the first frequency use status and the second frequency use status, and to decide, if it is determined that the harmonic is detected, a radio communication parameter in the first frequency band so as to use a frequency band used by the harmonic in radio communication.

Abstract: A radio communication apparatus which uses a first radio communication system that makes a radio communication by sharing frequencies with a second radio communication system, the apparatus includes a detection unit configured to detect an available frequency channel which fails to be used by the second radio communication system in a frequency band used by the first radio communication system, and a transmission unit configured to transmit, using the available frequency channel, a frame which includes a signal sequence which is used to identify whether or not the frame is transmitted by a radio communication terminal belonging to the first radio communication system by detecting the available frequency channel, the signal sequence being predetermined for the first radio communication system.

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: A data transmitting apparatus generates a block that includes identification information including the number of times divided data can be transmitted and data for error detection for detecting an error in the identification information associated with each other with respect to each divided data, and transmits the block to a data receiving apparatus. If the number of times divided data can be transmitted is one or more, the data transmitting apparatus stores the corresponding block in a transmission memory, and retransmits it upon a request for retransmission from the data receiving apparatus.

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 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 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 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: There is provided with a radio terminal which carries out data transmission using frequency bands licensed to other licensed radio terminals, including: a judging section configured to carry out a modulation analysis on a radio signal for each frequency band to judge whether the radio signal is a radio signal from a licensed radio terminal or not; a selection section configured to select a plurality of frequency bands; a schedule generation section configured to generate a schedule for intermittent data transmission; a data transmission section configured to transmit data according to the schedule; a carrier sensing section configured to carry out carrier sensing on a frequency band in which data is transmitted before data transmission for each the intermittent data transmission; and a control section configured to stop, when a radio signal from a licensed radio terminal is detected in a certain frequency band, data transmission using at least the certain frequency band.

Abstract: In a method for communication, first and second signals for timing synchronization are generated. Frequencies of the first and second signals are converted to other frequencies to obtain a first and second RF signals, which have a specific frequency gap therebetween. The first and second RF signals are combined to obtain a transmission signal, and the transmission signal is transmitted. When the transmission signal is received as a received signal, the frequency of the received signal is shifted by the specific frequency gap to obtain a converted signal. A complex conjugation of the converted signal calculated to obtain a complex conjugation signal. The received signal and the complex conjugation signal are multiplied to obtain a multiplication signal to calculate cross-correlation between a product of the first and second signals and the multiplication signal. A peak of the cross-correlation is detected to set a base time for timing synchronization.