Abstract: According to an embodiment, a communication apparatus includes a receiver, a first beacon processor, a second beacon processor, and an authentication processor. The receiver receives a first beacon transmitted over a wireless network while being protected by a first common key and a second beacon transmitted over the wireless network while not being protected by the first common key. The first beacon processor accesses the wireless network using information contained in the first beacon when the first common key is provided. The second beacon processor accesses the wireless network using information contained in the second beacon when the first common key is not provided. The authentication processor performs connection authentication to the wireless network using information contained in the second beacon and acquires the first common key.

Abstract: An orthogonal frequency division multiplexing (OFDM) signal transmission apparatus which transmits OFDM signals by using a plurality of transmission antennas includes a subcarrier setting device which sets signals for subcarriers so as to use some of the subcarriers of the OFDM signals as pilot subcarriers to transmit pilot signals and use the remaining subcarriers as data subcarriers to transmit data signals, the subcarrier setting device changing polarities of signals for the pilot subcarriers for each transmission antenna.

Abstract: A wireless communication apparatus according to an embodiment includes a transceiver and a transmission slot determiner. The transceiver transmits/receives information. The transmission slot determiner determines a transmission slot in which the transceiver transmits information, from a frame time-divided into a plurality of slots, based on the rank value of self node corresponding to the number of hops to a root node. A plurality of slot groups including a plurality of continuous slots is set in the frame. The slot groups are assigned different rank values. The transmission slot determiner selects a slot group to which the rank value of self node is assigned, and determines a transmission slot from among the slots included in the selected slot group.

Abstract: A communication device according to an embodiment is included in a multi-hop network. The communication device includes a holder, a storage, a switcher, and a controller. The holder holds communication data. The storage stores path information including an identifier that identifies a communication path and destination information that indicates a destination of communication data on the communication path. The switcher switches a communication path used to transmit communication data on the basis of the path information stored in the storage. The controller transmits communication data to a destination of a communication path switched by the switcher.

Abstract: A transmitter includes first generator to generate pilot source signal by modulating pilot sequence, second generator to generate data source signal with time length longer than that of pilot source signal by modulating data sequence, first cyclic shifter to perform cyclic shift of first shift amount to pilot source signal to generate first pilot signal, second cyclic shifter to performs cyclic shift of second shift amount to data source signal to generate first data signal, third cyclic shifter to perform cyclic shift of third shift amount to pilot source signal to generate second pilot signal, fourth cyclic shifter to perform cyclic shift of fourth shift amount to data source signal to generate second data signal, first transmit antenna to transmit first pilot signal and first data signal, and second transmit antenna to transmit second pilot signal and second data signal.

Abstract: According to an embodiment, a communication control device includes an acquisition unit, first and second authentication units, an output unit, and a connection permission unit. The acquisition unit acquires first authentication information for authenticating a communication device during initialization, via a first communication unit, from a terminal device that acquires and decodes encoded first authentication information. During initialization, the first authentication unit executes a connection authentication of the communication device via a second communication unit, based on the first authentication information. When the authentication is successful, the output unit encrypts second authentication information different from the first authentication information, and output the encrypted second authentication information to the communication device.

Abstract: A transmitter includes first generator to generate pilot source signal by modulating pilot sequence, second generator to generate data source signal with time length longer than that of pilot source signal by modulating data sequence, first cyclic shifter to perform cyclic shift of first shift amount to pilot source signal to generate first pilot signal, second cyclic shifter to performs cyclic shift of second shift amount to data source signal to generate first data signal, third cyclic shifter to perform cyclic shift of third shift amount to pilot source signal to generate second pilot signal, fourth cyclic shifter to perform cyclic shift of fourth shift amount to data source signal to generate second data signal, first transmit antenna to transmit first pilot signal and first data signal, and second transmit antenna to transmit second pilot signal and second data signal.

Abstract: A radio base station performs wireless communication with a wireless terminal. The radio base station includes a directivity pattern specifying unit, a communication unit, and a signal processor. The directivity pattern specifying unit specifies plural directivity patterns. The communication unit receives a search request frame from the wireless terminal, sends to the wireless terminal a search response frame which is a response to the search request frame, with at least one, specified by the directivity pattern specifying unit, of the directivity patterns, and receives a delivery acknowledgment frame for the search response frame from the wireless terminal with the directivity patterns specified by the directivity pattern specifying unit. The signal processor calculates, for each specified directivity pattern, a radio wave intensity of the delivery acknowledgment frame.

Abstract: According to one embodiment, a wireless terminal communicates with a server via wireless base stations. The wireless terminal has devices which transmit a signal in a normal-power transmission mode and the signal in a low-power transmission mode, a power control device which switches the normal-power transmission mode to the low-power transmission mode, or vice versa, and a device which transmits current position data to the server. The server detects the position of the wireless terminal, designates one of the base stations which is close to the wireless terminal, when the wireless terminal is set to the low-power transmission mod, and detects whether the base station designated has a problem or not according to detect the signal from the wireless terminal.

Abstract: According to an embodiment, a calculation method is for performing calculation on a wireless network including multiple terminals and multiple base stations. The method includes calculating a first probability with which a first base station and a second terminal are capable of connection with (h?1) hops, h being a finite integer equal to or larger than 2, and a first terminal and the second terminal are capable of direct connection with each other, by using a probability with which the first terminal and the second terminal are capable of direct connection with each other and a probability with which the second terminal and the first base station are capable of direct connection with each other; and calculating a second probability with which the first terminal is capable of connection with at least one of the base stations with h hops by using the first probability.

Abstract: According to an embodiment, a position calculation method includes obtaining a plurality of candidate positions each of which represents a position of a corresponding one of a plurality of base stations to be installed in a wireless network; calculating a condition of an optimization problem for deciding installation positions of base stations from the candidate positions by using probabilities of connection between a plurality of terminals included in the wireless network and the base stations installed at the candidate positions; and calculating the installation positions by solving the optimization problem under the condition.

Abstract: A transmitter includes first generator to generate pilot source signal by modulating pilot sequence, second generator to generate data source signal with time length longer than that of pilot source signal by modulating data sequence, first cyclic shifter to perform cyclic shift of first shift amount to pilot source signal to generate first pilot signal, second cyclic shifter to performs cyclic shift of second shift amount to data source signal to generate first data signal, third cyclic shifter to perform cyclic shift of third shift amount to pilot source signal to generate second pilot signal, fourth cyclic shifter to perform cyclic shift of fourth shift amount to data source signal to generate second data signal, first transmit antenna to transmit first pilot signal and first data signal, and second transmit antenna to transmit second pilot signal and second data signal.

Abstract: A communication device includes a signal processing device, a transceiver, and a controller. The signal processing device uses a first signal medium. The transceiver communicates with at least one of first devices by using a second signal medium. The controller controls usage of the first signal medium by the communication device and the at least one of first devices by communicating with the at least one of first devices by the transceiver.

Abstract: According to one embodiment, a monitoring apparatus includes a communication unit and a determination unit. The communication unit is configured to calculate a first indicator value and a second indicator value, the first indicator value relating to a received signal strength at a time when a packet transmitted from a first wireless device is received, the second indicator value relating to a received signal strength at a time when carrier sense is executed. The determination unit is configured to determine a state of the first wireless device to be one of three or more states, by performing a state determination using the first indicator value and the second indicator value, with a current state of the first wireless device being set as a basic point.

Abstract: According to one embodiment, a transmitting apparatus includes a generation unit, a division unit, an imparting unit and a transmitting unit. The generation unit generates first control information in accordance with a first information format. The division unit divides the first control information into control information pieces in accordance with information format divisions into which the first information format is divided and which include respective pointer regions, each of the information format divisions having a same data length as a second information format. The imparting unit imparts, to the pointer region of each of the information format divisions, a pointer indicating a wireless communication resource used to transmit one of the control information pieces corresponding to one of the information format divisions other than the each control information format division. The transmitting unit transmits the control information pieces.

Abstract: A transmitter includes first generator to generate pilot source signal by modulating pilot sequence, second generator to generate data source signal with time length longer than that of pilot source signal by modulating data sequence, first cyclic shifter to perform cyclic shift of first shift amount to pilot source signal to generate first pilot signal, second cyclic shifter to performs cyclic shift of second shift amount to data source signal to generate first data signal, third cyclic shifter to perform cyclic shift of third shift amount to pilot source signal to generate second pilot signal, fourth cyclic shifter to perform cyclic shift of fourth shift amount to data source signal to generate second data signal, first transmit antenna to transmit first pilot signal and first data signal, and second transmit antenna to transmit second pilot signal and second data signal.

Abstract: According to this embodiment, a position estimating device, that estimates a position of a target wireless device, includes a storage that stores positions of a plurality of reference wireless devices, a receiver which is notified of a received signal strength indicator value in signal transmission and reception between the target wireless device and each reference wireless device, a calculator that calculates a standard deviation for a probability distribution of a distance between the target wireless device and each reference wireless device, using the received signal strength indicator value, a first estimator that calculates an estimated distance between the target wireless device and each reference wireless device, using the received signal strength indicator value, and a second estimator that calculates the position of the target wireless device, using the standard deviation, the estimated distance, and the positions of the plurality of reference wireless devices.

Abstract: A wireless communication device transmits data to a relay destination being one of first relaying devices capable of communicating out of relaying devices; obtains first information, from each first relaying device, that indicates a representative value of remaining operating times of relaying devices present on a relay route from the first relaying device to a target device; determines to perform a new route search, based on the first information; increases a transmission power; then transmits a request; receive responses from all or a part of second relaying devices, which are relaying devices that have received the request, including pieces of second information each of which indicates a representative value of remaining operating times of relaying devices present on a relay route from the second relaying device to the target device; and selects a relay destination of data from among the second relaying devices based on the pieces of second information.

Abstract: There is provided a radio power transmitting apparatus including: a power transmitting coil, a band signal generating unit, a reflected signal measuring unit, an oscillator and a communication control unit. The coil is supplied with a signal and transmits the signal to a power receiving coil on a radio power receiving apparatus through magnetic coupling. The generating unit generates a band signal having an allowable transmission band and supplies the band signal to the power transmitting coil. The reflected signal measuring unit measures a reflected signal of the band signal from the power transmitting coil. The oscillator generates a carrier signal having a controllable oscillating frequency. The control unit determines a transmission frequency based on a frequency characteristic of the reflected signal and performs control so that a transmission signal generated by modulating the carrier signal of the transmission frequency is supplied to the power transmitting coil.

Abstract: Broadcast data is divided into a plurality of broadcast channels. Any of the plurality of broadcast channels is placed on a predetermined subcarrier in each of a plurality of main bands such that the placed broadcast channels differ from each other in a same frame and are consecutive in a predetermined order in a frame direction. The subcarriers are converted into a transmit RF signal and the transmit RF signal is transmitted.