Abstract: One of a plurality of radio terminals that transmit radio signals to a radio base station under a space multiplexing scheme, including a receiving unit that receives an access right request signal with respect to the radio base station from an other radio terminal, a prevention unit that prevents transmission of radio signals when receiving radio signals directed to an other radio terminal, a cancellation unit that cancels the prevention of transmission when receiving an access right assignment signal during the prevention of transmission and a transmitting unit that transmits a data signal to the radio base station according to the assignment signal, wherein radio signals are transmitted to the radio base station simultaneously with the other radio terminals and under the space multiplexing scheme.

Abstract: A wireless communication apparatus which can simultaneously conduct communication on at least two frequency channels is described. The apparatus includes a communication unit which refers to a connection management table to determine a communication system which can be used by a wireless communication terminal using an identifier of the wireless communication terminal, and conducts communication with the wireless communication terminal on a second frequency channel using the communication system, when a request from the wireless communication terminal to change the first frequency channel to the second frequency channel is permitted.

Abstract: A wireless communication apparatus which can simultaneously conduct communication on at least two frequency channels is described. The apparatus includes a communication unit which refers to a connection management table to determine a communication system which can be used by a wireless communication terminal using an identifier of the wireless communication terminal, and conducts communication with the wireless communication terminal on a second frequency channel using the communication system, when a request from the wireless communication terminal to change the first frequency channel to the second frequency channel is permitted.

Abstract: An information processing apparatus includes a receiving unit and a determining unit. The receiving unit receives read information that is read by a reading unit from a storage medium a plurality of number of times. The determining unit determines abnormality in a reading process performed by the reading unit, based on a first result acquired by comparing a time interval of reading the read information with a first threshold, or on a second result acquired by comparing the number of times the reading is performed with a second threshold.

Abstract: A wireless communication apparatus includes a transmitter that transmits a first frame and a second frame with multiplexing and a receiver that receives a third frame sent in response to the first frame and a forth frame sent in response to the second frame, wherein a first receipt completion timing at which the third frame is fully received by the receiver and a second receipt completion timing at which the forth frame is fully received by the receiver are synchronized by controlling at least one of first content of the first frame, a first transmission method by which the first frame is sent, second content of the second frame and a second transmission method by which the second frame is sent.

Abstract: A wireless communication apparatus includes a transmitter that transmits a first frame and a second frame with multiplexing and a receiver that receives a third frame sent in response to the first frame and a forth frame sent in response to the second frame, wherein a first receipt completion timing at which the third frame is fully received by the receiver and a second receipt completion timing at which the forth frame is fully received by the receiver are synchronized by controlling at least one of first content of the first frame, a first transmission method by which the first frame is sent, second content of the second frame and a second transmission method by which the second frame is sent.

Abstract: A wireless communication system includes a first tag installed on a ground outside a track for a running train, the first tag being driven by wirelessly received power, a second tag installed outside a side face of the train and above the first tag, the side face extending in a running direction, the second tag being driven by wirelessly received power, a wireless communicator which is installed in the train and performs wireless communication with the first tag and the second tag, and an antenna which is installed in the train and has a gain in directions of the first tag and the second tag.

Abstract: A wireless communication apparatus which can simultaneously conduct communication on at least two frequency channels is described. The apparatus includes a communication unit which refers to a connection management table to determine a communication system which can be used by a wireless communication terminal using an identifier of the wireless communication terminal, and conducts communication with the wireless communication terminal on a second frequency channel using the communication system, when a request from the wireless communication terminal to change the first frequency channel to the second frequency channel is permitted.

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: A wireless communication apparatus which can simultaneously conduct communication on at least two frequency channels is described. The apparatus includes a communication unit which refers to a connection management table to determine a communication system which can be used by a wireless communication terminal using an identifier of the wireless communication terminal, and conducts communication with the wireless communication terminal on a second frequency channel using the communication system, when a request from the wireless communication terminal to change the first frequency channel to the second frequency channel is permitted.

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: A communication device includes a receiver, a transmitter and an interruption module. The receiver receives an allocation signal indicating a first period usable by the communication device and a second period usable by a plurality of communication devices including the communication device. The transmitter transmits a transmission signal in the first period. If the transmission of the transmission signal is completed within the first period, the interruption module interrupts at least a part of power supply to the receiver in the second period. If the transmission of the transmission signal is not completed within the first period and directivity of radio waves used by a second communication device includes a direction of the communication device in a communication period allocated before the second period, the transmitter transmits the transmission signal in the second period.

Abstract: A wireless communication apparatus includes a transmitter that transmits a first frame and a second frame with multiplexing and a receiver that receives a third frame sent in response to the first frame and a forth frame sent in response to the second frame, wherein a first receipt completion timing at which the third frame is fully received by the receiver and a second receipt completion timing at which the forth frame is fully received by the receiver are synchronized by controlling at least one of first content of the first frame, a first transmission method by which the first frame is sent, second content of the second frame and a second transmission method by which the second frame is sent.

Abstract: A wireless communication apparatus includes a transmitter that transmits a first frame and a second frame with multiplexing and a receiver that receives a third frame sent in response to the first frame and a forth frame sent in response to the second frame, wherein a first receipt completion timing at which the third frame is fully received by the receiver and a second receipt completion timing at which the forth frame is fully received by the receiver are synchronized by controlling at least one of first content of the first frame, a first transmission method by which the first frame is sent, second content of the second frame and a second transmission method by which the second frame is sent.

Abstract: A wireless communication apparatus which can simultaneously conduct communication on at least two frequency channels is described. The apparatus includes a communication unit which refers to a connection management table to determine a communication system which can be used by a wireless communication terminal using an identifier of the wireless communication terminal, and conducts communication with the wireless communication terminal on a second frequency channel using the communication system, when a request from the wireless communication terminal to change the first frequency channel to the second frequency channel is permitted.

Abstract: A wireless communication apparatus which can simultaneously conduct communication on at least two frequency channels is described. The apparatus includes a communication unit which refers to a connection management table to determine a communication system which can be used by a wireless communication terminal using an identifier of the wireless communication terminal, and conducts communication with the wireless communication terminal on a second frequency channel using the communication system, when a request from the wireless communication terminal to change the first frequency channel to the second frequency channel is permitted.

Abstract: A wireless communication apparatus includes a transmitter that transmits a first frame and a second frame with multiplexing and a receiver that receives a third frame sent in response to the first frame and a forth frame sent in response to the second frame, wherein a first receipt completion timing at which the third frame is fully received by the receiver and a second receipt completion timing at which the forth frame is fully received by the receiver are synchronized by controlling at least one of first content of the first frame, a first transmission method by which the first frame is sent, second content of the second frame and a second transmission method by which the second frame is sent.

Abstract: One of a plurality of radio terminals that transmit radio signals to a radio base station under a space multiplexing scheme, including a receiving unit that receives an access right request signal with respect to the radio base station from an other radio terminal, a prevention unit that prevents transmission of radio signals when receiving radio signals directed to an other radio terminal, a cancellation unit that cancels the prevention of transmission when receiving an access right assignment signal during the prevention of transmission and a transmitting unit that transmits a data signal to the radio base station according to the assignment signal, wherein radio signals are transmitted to the radio base station simultaneously with the other radio terminals and under the space multiplexing scheme.

Abstract: A wireless communication apparatus includes: a communication module configured to wirelessly communicate with first and second counterpart communication apparatuses through a wireless channel during a period in which the wireless channel is allowed to be exclusively used, wherein the communication module multiplexes first and second data frames and transmits the first and second data frames to the first and second counterpart communication apparatuses, wherein the communication module completes receiving first and second receipt confirmation frames being respectively sent from the first and second counterpart communication apparatuses at first and second receipt completion timings, the second receipt completion timing being in synchronization with the first receipt completion timing, and wherein the communication module transmits a next first data frame and a next second data frame after elapse of a given time from the first receipt completion timing and the second receipt completion timing.

Abstract: One of a plurality of radio terminals that transmit radio signals to a radio base station under a space multiplexing scheme, including a receiving unit that receives an access right request signal with respect to the radio base station from an other radio terminal, a prevention unit that prevents transmission of radio signals when receiving radio signals directed to an other radio terminal, a cancellation unit that cancels the prevention of transmission when receiving an access right assignment signal during the prevention of transmission and a transmitting unit that transmits a data signal to the radio base station according to the assignment signal, wherein radio signals are transmitted to the radio base station simultaneously with the other radio terminals and under the space multiplexing scheme.