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 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 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.

Abstract: According to one embodiment, a wireless communication apparatus using a first wireless communication scheme includes a transmitter and controller. The controller which controls IFSs so as to set, one of the first IFS and the second IFS as an IFS used during the first period. the controller sets the second IFS to at least a second period when a channel is idle during a period corresponding to a fourth IFS after one of the IFS is switched from the first IFS to the second IFS and when the channel becomes busy after the period corresponding to the fourth IFS is elapsed, the fourth IFS being an IFS before the transmission of a beacon signal, the second period being one of a plurality of first periods and being a period which includes timing for an estimated cycle of the beacon signal.

Abstract: According to one embodiment, a wireless communication apparatus is provided with first and second determination units. The first unit determines based on a first carrier sense threshold whether busy state or not and specifies a first time when busy state is determined with the first threshold, and determines based on a second carrier sense threshold smaller than the first threshold whether busy state or not and specifies a second time when busy state is determined. The second unit determines, if at least busy state is determined based on the second threshold and the second time precedes a reference time equal to or earlier than the first time, to perform processing for avoiding interference.

Abstract: A wireless communication apparatus in a first wireless system is provided with first, second and third units, and a controller. The first unit transmits frames over a frequency channel using a short or long IFS as compared with a specific one used in a second wireless system with a communication range wider than the first wireless system. The second unit receives frames over the channel. The third unit determines an error characteristic in the received frames and/or a busy status of the channel. The controller controls at least either one of whether to change the frequency channel or not, and whether to change a duration of an interframe space or not.

Abstract: According to one embodiment, a wireless communication apparatus has a transmitter, a receiver, and a transmission timing instructor. The transmitter transmits a signal by using a first wireless communication scheme. The receiver receives a signal transmitted by using the first wireless communication scheme. The receiver detects a signal of which a frequency band includes at least a part of a frequency band used in the first wireless communication scheme, which is other than a signal transmitted by using the first wireless communication scheme. The transmission timing instructor instructs the transmitter to transmit a signal by using the first wireless communication scheme if the receiver does not receive a signal over a predetermined time from a detection of a signal other than a signal transmitted by using the first wireless communication scheme.

Abstract: According to one embodiment, a wireless communication apparatus includes a transceiver, an estimator and a controller. The transceiver transmits and receives a frame in a frequency band which is used by a first system executing communication in a first communication range determined by a first transmission power and a first antenna gain. The estimator determines whether an amount of interference in the frequency band from a second system is no less than a threshold, the second system executing communication in a second communication range which is larger than the first communication range and which is determined by a second transmission power and a second antenna gain. The controller increases a transmission power when the amount of interference is no less than the threshold.

Abstract: According to one embodiment, a wireless communication apparatus is provided with first and second determination units. The first unit determines based on a first carrier sense threshold whether busy state or not and specifies a first time when busy state is determined with the first threshold, and determines based on a second carrier sense threshold smaller than the first threshold whether busy state or not and specifies a second time when busy state is determined. The second unit determines, if at least busy state is determined based on the second threshold and the second time precedes a reference time equal to or earlier than the first time, to perform processing for avoiding interference.

Abstract: A wireless communication apparatus performs access control which starts transmission after a backoff time passes since an available state of a channel is detected through carrier sense, the backoff time being set based on a random value selected within a contention window width. The wireless communication apparatus includes a remaining time calculating unit which calculates a remaining time until a request delay time time-outs after data is generated, and a setting unit which sets the contention window width according to the remaining time calculated by the remaining time calculating unit.

Abstract: According to one exemplary embodiment, a communication apparatus includes: a measurement module which measures reception power of each field; a determination module which determines whether the reception power is within a range; a calculator which calculates a gain using the reception power if the reception power is not within the range; an adjuster which adjusts a field according to one of an initial gain and the calculated gain; a selector which selects a field length according to the number of field adjustments by the adjuster; and a transmitter which transmits information regarding the field length. When the number of the adjustments is lower than a first threshold value, the selector selects a first value, and when the number of the adjustments is equal to or higher than the first threshold value, the selector selects a second value that is higher than the first value, as the field length.

Abstract: In a wireless system of one embodiment, a first wireless device includes a first transmitter which transmits an end-of-transmission notification, and a first receiver which receives a change request signal sent from a second wireless device receiving the end-of-transmission notification. The second wireless device includes a second receiver which receives the end-of-transmission notification, and a second transmitter which transmits a change request signal when the end-of-transmission notification is received. The first transmitter transmits a signal at a longer interval after the first receiver receives the change request signal, and the second transmitter transmits a signal at a shorter interval after the second transmitter transmits the change request signal.

Abstract: In a wireless system of one embodiment, a first wireless device includes: a first transmitter which transmits an end-of-transmission notification; and a first receiver which receives a change request signal sent from a second wireless device receiving the end-of-transmission notification. The second wireless device includes: a second receiver which receives the end-of-transmission notification; and a second transmitter which transmits a change request signal when the end-of-transmission notification is received. The first transmitter transmits a signal at a longer interval after the first receiver receives the change request signal, and the second transmitter transmits a signal at a shorter interval after the second transmitter transmits the change request signal.

Abstract: According to one embodiment, a radio apparatus includes: a radio unit; a timer configured to count a first measurement time; a control unit configured to establish a first mode if the first measurement time is shorter than a first time, and establish a second mode if the first measurement time is longer than or equal to the first time; and a power control unit configured to control power to be supplied to the radio unit if the first mode is set and next data is not received even if a second time elapsed, and control power to be supplied to the radio unit if the second mode is set and next data is not received even if a third time elapsed, wherein the radio unit makes a transition to a sleep mode as a result of a power control by the power control unit.

Abstract: In general, according to one embodiment, there is provided a wireless communication apparatus used for asymmetrical communication, in which frame transmission at a first interval and frame transmission at a second interval longer than the first interval are performed. The apparatus includes a receiver, an interval controller, and a transmitter. The receiver receives a frame for which a flag requesting transmission of an acknowledgement is set. The interval controller changes the first interval to a third interval longer than the second interval in response to reception of the frame. The transmitter performs frame transmission at the third interval.

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: According to one embodiment, a communication device includes a first wireless device configured to transmit a signal and a second wireless device configured to transmit a positive acknowledge when reception of the signal is successful. In the first wireless device, a first controller controls a first transmission module to change a first frequency channel based on a change order stored in a first storage when the positive acknowledge is not received even after the time measured by a first timer exceeds a first period. In the second wireless device, a second controller controls a second reception module to change the first frequency channel based on the change order stored in a second storage when the positive acknowledge is not transmitted even after the time measured by a second timer exceeds the first period.

Abstract: According to one embodiment, a wireless communication apparatus includes a first and a second processing unit. The first processing unit generates a control signal related to connection settings. The second processing unit supports wireless systems and is configured to transmit a first frame including first information related to at least one of the plurality of wireless systems by any of the wireless systems, grasp, based on a second frame received from another wireless communication apparatus, a wireless system supported by the other wireless communication apparatus, select a wireless system used for data exchange with the other wireless communication apparatus based on the second information indicating the grasped wireless system.

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.