Nippon Telegraph and Telephone Corporation

Nippon Telegraph Telephone Corporation

Koichi Ishihara

Yasushi Takatori

Tomoki Murakami

Hirantha Abeysekera

Toshiro Nakahira

Takafumi Hayashi

Masato Mizoguchi

Riichi Kudo

Etsushi Yamazaki

Yusuke Asai

Takayuki Kobayashi

Shoko Shinohara

Takeo Ichikawa

Munehiro Matsui

Tadao Nakagawa

Yutaka Miyamoto

Akihide Sano

Eiji Yoshida

Masahito Tomizawa

Yasuhiko Inoue

Yoshiaki Kisaka

Shogo Yamanaka

Tomoyoshi Kataoka

Mamoru Akimoto

Seiji Okamoto

Kengo Horikoshi

Mitsuteru Yoshida

Riku Omiya

Hideyuki Nosaka

Kazushige Yonenaga

Tomoyuki Yamada

Takatsune Moriyama

Eiichi Yamada

Mitsuteru Ishikawa

Naoki Fujiwara

Masanori Nakamura

Hiroyuki Uzawa

Daisuke Murayama

Takuya Ohara

Daisuke Goto

Kenichi Kawamura

Tomoaki Kumagai

Kohki Shibahara

Syuji Kubota

Wenjie Jiang

Motoharu Sasaki

A wireless communication system including, a primary transmitting station and a primary receiving station which are being in communication, a secondary transmitting station and one or more secondary receiving stations which use the identical frequency that are used in the above wireless environment, the one or more secondary receiving stations including a secondary receiving station serving as a destination, the secondary receiving station serving as the destination receiving a transmitted signal from the secondary transmitting station, the wireless communication system including a plurality of relay stations located between the secondary transmitting station and the one or more secondary receiving stations, wherein the secondary transmitting station includes a relay station selection unit configured to select at least one relay station that relays the transmitted signal from among the plurality of relay stations, add information for turning on the at least one selected relay station to the transmitted signal, and transmit the transmitted signal, the at least one selected relay station is configured to be turned on in accordance with the information of the transmitted signal to perform a non-regenerative relay of the transmitted signal, and the secondary receiving station serving as the destination is configured to receive the transmitted signal relayed via the at least one relay station that is turned on.

Radio communication apparatus, and radio communication method

A wireless communication device that detects a vacant channel by carrier sensing from among a plurality of channels and performs communication using the vacant channel includes a carrier sensing unit configured to divide channels to be carrier sensed between a wireless station and a surrounding wireless station, acquire a result of carrier sensing from the surrounding wireless station, and share results of carrier sensing from the wireless station and the surrounding wireless station to detect the vacant channel.

Wireless communication device and wireless communication control method

In a wireless communication system including a plurality of base stations to which terminal stations are connectable, and a monitoring station which monitors each of the base stations, the monitoring station includes an information collection unit configured to collect wireless environment information including a plurality of information items indicating wireless environments around the base stations and the terminal stations, from each of the base stations, a defect detection unit configured to detect whether or not one or more defects occur based on a combination of the information items, and a defect determination unit configured to determine estimated occurrence probabilities of the defects detected by the defect detection unit based on a combination of the information items.

Wireless communication system, monitoring station, defect detection method, and wireless communication program

A radio signal strength information calculation method performed by a control apparatus includes: calculating radio information regarding each of a plurality of meshes into which an area where base stations are placed is divided and generating mesh radio information; and placing a virtual base station at a position to where any of the base stations would be moved in the area, and calculating radio signal strength information between a plurality of base stations including the base stations and the virtual base station based on the mesh radio information.

Radio signal strength information calculation method, control apparatus and program

Interference in preamble signals and pilot signals in cooperative transmission using interference suppressing technology is avoided. A wireless apparatus for transmitting a wireless signal on which directivity control has been performed to stations in a wireless system including at least one wireless apparatus is provided with a known signal generating unit which generates a known signal to be added to the wireless signal, a weighting processing unit which performs weighting on the known signal generated by the known signal generating unit, and a wireless processing unit which transmits the known signal on which the weighting has been performed by the weighting processing unit.

Wireless signal transmitting method and wireless apparatus

A radio communication method of connecting a base station with a plurality of terminal stations, the base station including a plurality of radio communication units compatible with a plurality of communication standards or communication schemes, the method including collecting, from each of the plurality of terminal stations, communication quality information representing a communication quality of the terminal station, collecting, from each of the plurality of terminal stations, communication performance information representing a communication performance of the terminal station, collecting, from each of the plurality of terminal stations, identifier information that identifies the terminal station, calculating, based on the communication quality information, the communication performance information and the identifier information that are collected, a setting policy including a setting for each of the plurality of radio communication units, and a switching policy of setting a condition for switching the plurality of radio communication units, and setting, for each of the plurality of radio communication units, the terminal station to be connected based on the setting policy and the switching policy that are calculated.

Wireless communication method, base station, and wireless communication system

A wireless communication system includes a plurality of base stations to which terminal stations are connectable, and a base station control device controlling each of the base stations. The base station control device includes an information collection unit collecting wireless environment information indicating wireless environments around the base stations and the terminal stations from each of the base stations, and a policy calculation unit calculating a policy for connecting the base stations and the terminal stations based on the wireless environment information. Each of the base stations includes receiver receiving the calculated policy a destination calculation unit calculating a destination to which a terminal station left unaccommodated is to be connected based on the received policy, and a transmitter transmitting the received policy and the calculated destination to the terminal station. Each of the terminal stations determines a connection destination based on the transmitted policy and transition destination.

Wireless communication system, communication control method, and communication control program

A wireless communication system includes a plurality of base stations to which one or more terminal stations are connectable, and a base station control device controlling each of the plurality of base stations. The base station control device includes an information collection unit collecting connection information regarding the terminal stations connected to the base stations from each of the base stations, a list generation unit generating a white list indicating the terminal stations allowed to be connected to the base stations for each of the base stations based on the connection information, and a transmission unit configured to transmit the white list to each of the base stations. Each of the base stations includes a reception unit receiving the white list, and a setting unit performing setting so as to allow or inhibit connection of each of the terminal stations to the base station based on the received white list.

Wireless communication system, base station control device, communication control method, and communication control program

A wireless performance evaluation method for performing wireless performance evaluation of a wireless network including wireless base stations and wireless terminal stations includes: before performing wireless performance evaluation operation based on wireless performance evaluation information generated from wireless performance evaluation conditions, determining whether an existing wireless performance evaluation result of wireless performance evaluation operation that has been performed is substitutable or not; and if the existing wireless performance evaluation result is substitutable, skipping arithmetic processing corresponding to the wireless performance evaluation information and substituting the existing wireless performance evaluation result.

Wireless performance evaluation method and wireless performance evaluation system

A wireless communication system includes a base station to which a plurality of terminal stations are connectable and a control unit that controls the base station. The base station includes a collection unit that collects terminal station information indicating terminal stations each having issued a connection request to the base station, an information processing unit that causes a storage unit to store connected terminal station information indicating, among the terminal stations indicated by the terminal station information, the terminal station currently being connected to the base station, a network communication unit that receives, from the control station, base station control information for controlling a response to the connection request from the terminal station that is not indicated by the connected terminal station information, and a connection determination unit that determines, based on each of the connected terminal station information and the base station control information, whether or not the connection request from the terminal station that is not indicated by the connected terminal station information is to be refused. The control station transmits, when a predetermined condition is satisfied, to the base station, the base station control information indicating that the connection request from the terminal station that is not indicated by the connected terminal station information is to be refused.

Wireless communication system, base station, and wireless communication method

Included are a plurality of base stations to which a plurality of terminal stations are connectable and a control station that controls each of the base stations. The control station includes a network communication unit that receives, from each of the base stations, base station information indicating the base station, wireless environment information indicating a reception signal received by the base station from another of the base stations and a signal intensity thereof, and terminal station information indicating the terminal station connected to the base station and a signal intensity and a calculation unit that calculates, based on the base station information, the wireless environment information, and the terminal station information each received from each of the base stations, connection control information for controlling a connection permission from each of the base stations to each of the terminal stations. Each of the base stations includes a connection control unit that controls, based on the connection control information, the connection permission to each of the terminal stations.

Wireless communication system, control station, base station, and wireless communication method

An embodiment of the present invention is a local wireless communication system that emits a radio wave in a licensed band to form a wireless communication environment in a predetermined area. The system includes a base station configured to emit a radio wave, a plurality of sensors disposed along an edge of the area, and a control apparatus. The sensors each measure a radio field intensity of the radio wave emitted from the base station, and feed the radio field intensity back to the control apparatus via the base station. The control apparatus controls a transmission power of the radio wave from the base station to control the fed radio field intensity.

Local wireless communication system, radio field intensity control method, control device, and program

A radio communication method of connecting a base station with a plurality of terminal stations, the base station including a plurality of radio communication units compatible with a predetermined communication standard, the method including collecting additional-line information including information regarding whether each terminal station is compatible with additional communication standard; collecting request information including a request in the predetermined communication standard of each terminal station; collecting identifier information that identifies each terminal station; calculating, based on the additional-line information, the request information and the identifier information that are collected, a setting policy including a setting for each radio communication unit, and a switching policy of setting a condition for switching the plurality of radio communication units; and setting, for each radio communication unit, the terminal station to be connected based on the setting policy and the switching policy that are calculated.

A communication control method for controlling transmission powers transmitted by a plurality of base stations in a coverage area, the coverage area being covered by the plurality of base stations includes setting a transmission power of each base station to a maximum, calculating, for each base station, a percentage of an individual coverage area with respect to the coverage area when the transmission power of each base station is set to the maximum, the individual coverage area serving as a range in which each base station individually accommodates a terminal station, reducing, when a maximum value of the calculated percentages deviates from an average value by a predetermined value or greater, the transmission power of any of the plurality of base stations with the maximum percentage value, newly calculating, for each base station, a percentage of the individual coverage area with respect to the coverage area, and continuing the control until the maximum value of the calculated percentages deviates from the average value by less than the predetermined value.

Communication control method, control station, and communication control program

A method includes collecting, as environment information, a radio environment represented by a signal received at a plurality of radio communication units from another base station, each of the plurality of radio communication units being switchable between a normal mode in which the radio communication unit performs radio communication as a base station and a subordinate mode in which the radio communication unit performs radio communication as a virtual terminal station, calculating test conduct information for each base station based on base station performance information representing a performance of each base station and the environment information, and conducting an operation test of each base station by, based on the test conduct information, setting any of the radio communication units to the normal mode, switching the radio communication units of the other base station to the subordinate mode, and performing radio communication with each other.

Base station operation test method, wireless communication system, and base station

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Yokosuka, Japan

Koichi Ishihara