Abstract: A BAN system includes multiple terminal apparatuses connected by wireless communication, where a terminal apparatus of the multiple terminal apparatuses is configured to identify in which direction acceleration has changed, the direction being identified based on a measurement result of a sensor of the terminal apparatus, the sensor being configured to measure acceleration; and to refer to information that specifies corresponding to places where the plurality of terminal apparatuses is to be attached to a body, directions in which acceleration changes when the body performs a given behavior, and determines based on the identified direction, a place where the terminal apparatus is attached to the body.

Abstract: A communication device includes a memory, and a processor coupled to the memory and configured to transmit a first packet including a first information within a contention-free period assigned to the communication device, the first packet storing last data to be transmitted in the contention-free period, the first information indicating presence of remaining data to be transmitted in the contention-free period, and, after transmit the first packet, to transmit a second packet including a second information within the contention-free period, the second information indicating absence of remaining data to be transmitted in the contention-free period.

Abstract: A calculation unit computes, based on subsequent information that is added to data transmitted from a terminal device and indicates the presence or absence of untransmitted data reserved in the terminal device when transmitting the data, the number of data in which untransmitted data exists among the certain number of data previously transmitted from the terminal device. A time slot assignment control unit controls the assigned size of a time slot to the terminal device based on the number of the data, in which untransmitted data exists, computed by the calculation unit. A data processing unit notifies the terminal device of the assigned size of the time slot determined by the time slot assignment control unit.

Abstract: A communication apparatus includes: a judgment section configured to judge a request for delay guarantee for data transmission; a route selection section configured to: select a first route including a mean delay time meeting a first condition, from routes available between the communication apparatus and a second communication apparatus which are in a network of wireless communication, when the request is a first request; and select a second route including a probability of successful data transmission for a given number of transmissions meeting a second condition, from the routes, when the request is a second request; and a transmission section configured to transmit the data to one of the first route and the second route.

Abstract: A wireless communication system includes first and second wireless communication apparatuses. The first wireless communication apparatus includes a plurality of communication units that perform communication in different frequency bands. The plurality of communication units transmits the same control signal and data in the different frequency bands to keep allocation of communication slots for the second wireless communication apparatus on a plurality of paths. When detecting a communication failure while connecting to and communicating with one communication unit through one path, the second wireless communication apparatus switches to another communication unit and continues the communication through another path.

Abstract: A BAN system includes multiple terminal apparatuses connected by wireless communication, where a terminal apparatus of the multiple terminal apparatuses is configured to identify in which direction acceleration has changed, the direction being identified based on a measurement result of a sensor of the terminal apparatus, the sensor being configured to measure acceleration; and to refer to information that specifies corresponding to places where the plurality of terminal apparatuses is to be attached to a body, directions in which acceleration changes when the body performs a given behavior, and determines based on the identified direction, a place where the terminal apparatus is attached to the body.

Abstract: A radio communication terminal includes an acquisition unit configured to acquire property information indicating a property that is used when a data communication route, on which data communication is performed with other radio communication terminals, is determined, a calculator configured to calculate variation of the property by using the acquired property information, and a controller configured to change a determination reference for whether to change the data communication route in response to the calculated variation of the property.

Abstract: A wireless communication system includes a transmission device, a relay device, and a reception device and is configured to execute direct communication of directly transmitting a wireless signal from the transmission device to the reception device without routing through the relay device and indirect communication of indirectly transmitting a wireless signal from the transmission device to the reception device through the relay device. The wireless communication system includes a controller configured to estimate a disconnection continuation time that is a time during which the direct communication is not executable in a case where the direct communication is not executable while the direct communication is repeatedly executed, continue to execute the direct communication when the disconnection continuation time is shorter than a threshold time, and execute the indirect communication when the disconnection continuation time is longer than the threshold time.

Abstract: A communication method for use in a communication system having a plurality of communication devices includes: a first communication device transmitting within a predefined period a connection request signal requesting a connection with another communication device; a second communication device transmitting a connection permit signal which contains the number of connection request signals received during the predefined period as the number of requesting candidates; the first communication device obtaining a transmission probability defining the probability of signal transmission such that the transmission probability decreases as the number of requesting candidates contained in the connection permit signal received from the second communication device increases; and the first communication device making a decision as to whether or not to transmit a signal out in accordance with the transmission probability at the timing that the signal can be transmitted to the second communication device.

Abstract: A wireless communication method includes: detecting, at a wireless communication apparatus, a collision of data transmitted from a plurality of wireless communication terminals during a first period that is in a communication-enabled state; shifting, when the collision has been detected, a second period, which belongs to the same frame as the first period and is in a communication-disabled state, to a communication-enabled state; transmitting, at the wireless communication apparatus, a request to the plurality of wireless communication terminals for retransmission of the data and receiving data transmitted from the plurality of wireless communication terminals in response to the request, using the shifted second period.

Abstract: A transmission control method performed in a communication apparatus, the transmission control method including: receiving a packet from a counterparty apparatus, measuring a quality of communication with the counterparty apparatus and the fluctuation amount of the quality, controlling a transmission so as to transmit a packet to the counterparty apparatus when the fluctuation amount is relatively large in accordance with a first level and the quality is relatively high in accordance with a second level, and not to transmit a packet to the counterparty apparatus when the fluctuation amount is relatively large in accordance with the first level and the quality is relatively low in accordance with the second level.

Abstract: A wireless communication device, including a radio transceiver data configured to transmit and to receive data packets to and from a base station, and a processor configured to compute a proportional hidden standby time being computed on the basis of at least two of from among a proportional exposed communication time, a proportional exposed collision time, and a proportional exposed standby time, to compute a predicted PER from the proportional hidden standby time computed; to compute a threshold value for the number of retransmission attempts on the basis of the predicted PER computed, and to cause the radio transceiver to repeat transmission of a data packet to the base station until the number of transmissions exceeds the threshold value computed in the case of failed transmission of a data packet to the base station by the radio transceiver.

Abstract: A communication apparatus includes: a judgment section configured to judge a request for delay guarantee for data transmission; a route selection section configured to: select a first route including a mean delay time meeting a first condition, from routes available between the communication apparatus and a second communication apparatus which are in a network of wireless communication, when the request is a first request; and select a second route including a probability of successful data transmission for a given number of transmissions meeting a second condition, from the routes, when the request is a second request; and a transmission section configured to transmit the data to one of the first route and the second route.

Abstract: A communication device includes a memory, and a processor coupled to the memory and configured to transmit a first packet including a first information within a contention-free period assigned to the communication device, the first packet storing last data to be transmitted in the contention-free period, the first information indicating presence of remaining data to be transmitted in the contention-free period, and, after transmit the first packet, to transmit a second packet including a second information within the contention-free period, the second information indicating absence of remaining data to be transmitted in the contention-free period.

Abstract: A wireless communication system includes first and second wireless communication apparatuses. The first wireless communication apparatus includes a plurality of communication units that perform communication in different frequency bands. The plurality of communication units transmits the same control signal and data in the different frequency bands to keep allocation of communication slots for the second wireless communication apparatus on a plurality of paths. When detecting a communication failure while connecting to and communicating with one communication unit through one path, the second wireless communication apparatus switches to another communication unit and continues the communication through another path.

Abstract: A base station apparatus that communicates with a radio communication terminal in a radio communication system, includes: processor configured to detect interference between the radio communication system and another radio communication system, and determine whether or not to switch a radio channel used to communicate with the radio communication terminal when the interference is detected; and a channel switching unit that switches the radio channel when the processor determines to switch the radio channel, and does not switch the radio channel when the processor determines not to switch the radio channel.

Abstract: A calculation unit computes, based on subsequent information that is added to data transmitted from a terminal device and indicates the presence or absence of untransmitted data reserved in the terminal device when transmitting the data, the number of data in which untransmitted data exists among the certain number of data previously transmitted from the terminal device. A time slot assignment control unit controls the assigned size of a time slot to the terminal device based on the number of the data, in which untransmitted data exists, computed by the calculation unit. A data processing unit notifies the terminal device of the assigned size of the time slot determined by the time slot assignment control unit.

Abstract: A transmission control method performed in a communication apparatus, the transmission control method including: receiving a packet from a counterparty apparatus, measuring a quality of communication with the counterparty apparatus and the fluctuation amount of the quality, controlling a transmission so as to transmit a packet to the counterparty apparatus when the fluctuation amount is relatively large in accordance with a first level and the quality is relatively high in accordance with a second level, and not to transmit a packet to the counterparty apparatus when the fluctuation amount is relatively large in accordance with the first level and the quality is relatively low in accordance with the second level.

Abstract: A wireless communication device, including a radio transceiver data configured to transmit and to receive data packets to and from a base station, and a processor configured to compute a proportional hidden standby time being computed on the basis of at least two of from among a proportional exposed communication time, a proportional exposed collision time, and a proportional exposed standby time, to compute a predicted PER from the proportional hidden standby time computed; to compute a threshold value for the number of retransmission attempts on the basis of the predicted PER computed, and to cause the radio transceiver to repeat transmission of a data packet to the base station until the number of transmissions exceeds the threshold value computed in the case of failed transmission of a data packet to the base station by the radio transceiver.

Abstract: A radio communication system including a base station apparatus including a first memory to store a schedule for communication using each of a plurality of set values of a predetermined communication element in the physical layer, a first antenna to communicate with a terminal apparatus using a first set value of the plurality of set values in accordance with the schedule stored in the first memory, and a first processor to select a second set value of the plurality of set values if the condition of communication performed with the terminal apparatus by the first antenna using the first set value has deteriorated, and cause the first antenna to perform communication using the selected second set value in accordance with the schedule and the terminal apparatus including a second memory to store the schedule, a second antenna to communicate with the base station apparatus, and a second processor.