Abstract: A communication device includes a wireless communication device, a location information acquisition device, a storage and a controller. The wireless communication device wirelessly communicates with a base station used as a connection destination. The location information acquisition device acquires location information on a location of the communication device. The storage stores historical communication information on past communication status. The controller determines a degree of risk of occurrence of reduction in an amount of available communication bandwidth beyond a tolerance limit based on the historical communication information and the location information. The controller further controls a transmission rate for communicating the data based on a result of determination of the degree of risk.

Abstract: In order to prospectively avoid communication failures or reduction in throughput of each user terminal, thereby improving users' satisfaction with communication service, a base station is configured to control wireless communication with a terminal device by using any of multiple transmission beams formed by the base station or those formed by another base station and includes a wireless communication device and a controller configured to acquire correction information used for correcting a measurement value for evaluating reception status of each transmission beam and cause the wireless communication device to transmit the correction information to the user terminal so as to thereby promote the user terminal to use, or inhibit the user terminal from using a specific transmission beam.

Abstract: To reduce power consumption and enable a quick change from one communication path to another when detecting a decrease in quality of communication for communicating user data, a first base station determines a second base station and a third base station, and then the first base station transmits a connection request message to a terminal, the second base station and the third base station concurrently with transmitting a communication request message to the second base station, and, while the second base station is in communication with the terminal, upon detecting a decrease in quality of communication with the terminal based on a reception status of an uplink signal from the terminal, the second base station transmits a path switching request message to the first base station, which in turn transfers the received path switching request message transmitted from the second base station to the third base station.

Abstract: To reduce power consumption and enable a quick change from one communication path to another when detecting a decrease in quality of communication for communicating user data, a first base station determines a second base station and a third base station, and then the first base station transmits a connection request message to a terminal, the second base station and the third base station concurrently with transmitting a communication request message to the second base station, and, while the second base station is in communication with the terminal, upon detecting a decrease in quality of communication with the terminal based on a reception status of an uplink signal from the terminal, the second base station transmits a path switching request message to the first base station, which in turn transfers the received path switching request message transmitted from the second base station to the third base station.

Abstract: A wireless terminal that: for previous communications between the wireless terminal and base stations, stores as a communication history at least position information for the wireless terminal and information pertaining to each base station; acquires the position information for the wireless terminal and, on the basis of the position information for the wireless terminal and the stored communication history, derives from multiple base stations at least a connection subject base station to be used in data communication and a connection standby base station, which is the base station having the next highest connection priority after the connection subject base station; and performs data communication when a trial connection with the connection subject base station has succeeded, and switches the connection subject base station to be used in data communication to the connection standby base station when communication with the connection subject base station is interrupted.

Abstract: A communication device includes a wireless communication device, a location information acquisition device, a storage and a controller. The wireless communication device wirelessly communicates with a base station used as a connection destination. The location information acquisition device acquires location information on a location of the communication device. The storage stores historical communication information on past communication status. The controller determines a degree of risk of occurrence of reduction in an amount of available communication bandwidth beyond a tolerance limit based on the historical communication information and the location information. The controller further controls a transmission rate for communicating the data based on a result of determination of the degree of risk.

Abstract: In order to enable efficient utilization of an available bandwidth by properly estimating the available bandwidth under conditions in which the available bandwidth significantly changes upon occurrence of communication path switching, an available bandwidth estimation is performed by estimating a current available bandwidth based on historical communication state information i.e.

Abstract: A communication device is provided and includes: a wireless communication device configured to wirelessly communicate with a base station used as a connection destination; a location information acquisition device configured to acquire location information on a location of the communication device; a storage configured to store historical obstruction information for an obstructed location where decrease in communication quality due to obstruction has occurred before; a controller configured to determine, based on the historical obstruction information and the location information, a degree of risk of occurrence of decrease in communication quality due to obstruction for at least one of a current connection destination that is currently used by the communication device and a future connection destination that is expected to be used by the communication device, and control the connection destination based on a result of determination of the degree of risk.

Abstract: In order to prospectively avoid communication failures or reduction in throughput of each user terminal, thereby improving users' satisfaction with communication service, a base station is configured to control wireless communication with a terminal device by using any of multiple transmission beams formed by the base station or those formed by another base station and includes a wireless communication device and a controller configured to acquire correction information used for correcting a measurement value for evaluating reception status of each transmission beam and cause the wireless communication device to transmit the correction information to the user terminal so as to thereby promote the user terminal to use, or inhibit the user terminal from using a specific transmission beam.

Abstract: A base station includes a memory holding information on P terminals in connecting to the base station, where P is an integer of 3 or more, a determination unit that determines L terminals to transmit a reference symbol used for measurement of channel state information indicating a state of a propagation path to the base station from among the P terminals based on the information on the P terminals, at every data transmission cycle, where L is an integer satisfying 2?L<P, a selector that selects M terminals capable of spatial multiplexing communication in the data transmission cycle based on a measurement result of the channel state information based on reception of the reference symbol transmitted from L terminals, where M is an integer satisfying 2?M?L, and receives respective pieces of data transmitted from the M terminals via a plurality of antennas.

Abstract: A base station is capable of wireless communication with a plurality of terminals, the base station includes a memory that holds information on P (P: an integer of 3 or more) terminals currently connected to the base station, a determination unit that determines L (L: an integer satisfying 2?L<P) terminals that are to report channel state information indicating a state of a propagation path to the base station from among the P terminals based on the information on the P terminals, at every data transmission cycle, a selector that selects M (M: an integer satisfying 2?M?L) terminals capable of spatial multiplex communication in the data transmission cycle based on the reporting of the channel state information from the L terminals, and a communicator that transmits data to and from the M terminals via a plurality of antennas using the spatial multiplex communication.

Abstract: A communication device is provided and includes: a wireless communication device configured to wirelessly communicate with a base station used as a connection destination; a location information acquisition device configured to acquire location information on a location of the communication device; a storage configured to store historical obstruction information for an obstructed location where decrease in communication quality due to obstruction has occurred before; a controller configured to determine, based on the historical obstruction information and the location information, a degree of risk of occurrence of decrease in communication quality due to obstruction for at least one of a current connection destination that is currently used by the communication device and a future connection destination that is expected to be used by the communication device, and control the connection destination based on a result of determination of the degree of risk.

Abstract: In order to properly control a communication bandwidth used for communication without increasing load of a network, a communication device includes a controller configured to control a communication bandwidth used for transmitting application data by using a congestion control algorithm, wherein, when a connection destination is changed, the controller acquires an initial value of the communication bandwidth appropriate for the connection destination based on an initial value table, and starts control of the communication bandwidth by using the initial value.

Abstract: To shorten time required to measure communication quality levels, a terminal device selects one of a first or second measurement scheme based on an amount of available bandwidth provided by a current cell in which the terminal device is currently present and other information. When the current cell is provides a largest amount of available bandwidth, the terminal device selects the first scheme, and when the current cell provides a smallest amount of available bandwidth, the terminal device selects the second scheme. When the first scheme is selected, the terminal device measures communication quality levels of communication with all peripheral cells, and when the second scheme is selected, the terminal device acquires current location information on the terminal device, and then extracts one or more of the peripheral cells based on current location information and historical communication information, and measures communication quality levels of communication with the extracted peripheral cells.

Abstract: To shorten time required to measure communication quality levels, a terminal device selects one of a or second measurement scheme based on an amount of available bandwidth provided by a current cell in which the terminal device is currently present and other information. When the current cell is provides a largest amount of available bandwidth, the terminal device selects the first scheme, and when the current cell provides a smallest amount of available bandwidth, the terminal device selects the second scheme. When the first scheme is selected, the terminal device measures communication quality levels of communication with all peripheral cells, and when the second scheme is selected, the terminal device acquires current location information on the terminal device, and then extracts one or more of the peripheral cells based on current location information and historical communication information, and measures communication quality levels of communication with the extracted peripheral cells.

Abstract: A base station includes a memory holding information on P terminals in connecting to the base station, where P is an integer of 3 or more, a determination unit that determines L terminals to transmit a reference symbol used for measurement of channel state information indicating a state of a propagation path to the base station from among the P terminals based on the information on the P terminals, at every data transmission cycle, where L is an integer satisfying 2?L<P, a selector that selects M terminals capable of spatial multiplexing communication in the data transmission cycle based on a measurement result of the channel state information based on reception of the reference symbol transmitted from L terminals, where M is an integer satisfying 2?M?L, and receives respective pieces of data transmitted from the M terminals via a plurality of antennas.

Abstract: In order to enable efficient utilization of an available bandwidth by properly estimating the available bandwidth under conditions in which the available bandwidth significantly changes upon occurrence of communication path switching, an available bandwidth estimation is performed by estimating a current available bandwidth based on historical communication state information i.e.

Abstract: A wireless terminal that: for previous communications between the wireless terminal and base stations, stores as a communication history at least position information for the wireless terminal and information pertaining to each base station; acquires the position information for the wireless terminal and, on the basis of the position information for the wireless terminal and the stored communication history, derives from multiple base stations at least a connection subject base station to be used in data communication and a connection standby base station, which is the base station having the next highest connection priority after the connection subject base station; and performs data communication when a trial connection with the connection subject base station has succeeded, and switches the connection subject base station to be used in data communication to the connection standby base station when communication with the connection subject base station is interrupted.

Abstract: A base station is capable of wireless communication with a plurality of terminals, the base station includes a memory that holds information on P (P: an integer of 3 or more) terminals currently connected to the base station, a determination unit that determines L (L: an integer satisfying 2?L<P) terminals that are to report channel state information indicating a state of a propagation path to the base station from among the P terminals based on the information on the P terminals, at every data transmission cycle, a selector that selects M (M: an integer satisfying 2?M?L) terminals capable of spatial multiplex communication in the data transmission cycle based on the reporting of the channel state information from the L terminals, and a communicator that transmits data to and from the M terminals via a plurality of antennas using the spatial multiplex communication.