Nippon Telegraph and Telephone Corporation

Yasushi Takatori

Takahiro Asai

Akira Yamada

Yukihiko Okumura

Takayuki Kobayashi

Koichi Ishihara

Hirantha Abeysekera

Tomoki Murakami

Toshiro Nakahira

Takafumi Hayashi

Masato Mizoguchi

Riichi Kudo

Shoko Shinohara

Munehiro Matsui

Takeo Ichikawa

Yasuhiko Inoue

Yusuke Asai

Yutaka Miyamoto

Keisuke Wakao

Toshikazu Hori

Shota Nakayama

Takatsune Moriyama

Hideyuki Nosaka

Etsushi Yamazaki

Akihide Sano

Eiji Yoshida

Tadao Nakagawa

Kenichi Kawamura

Kentaro Nishimori

Riku Omiya

Akira Kishida

Keizo Cho

Tomoaki Ogawa

Tomoyuki Yamada

Shogo Yamanaka

Kengo Nagata

Masashi Iwabuchi

Mamoru Akimoto

Yoshifumi Morihiro

Takefumi Hiraguri

Akiyoshi Inoki

Hiroshi Nakamoto

Wataru Yamada

Hayato Fukuzono

Yasufumi Morioka

Shinya Otsuki

Daisuke Goto

Hiroto Yasuda

Eiichi Yamada

Syuji Kubota

Wenjie Jiang

Motoharu Sasaki

Mitsuki Nakamura

Nobuaki Kuno

Yoghitha Ramamoorthi

Hirantha Sithira Abeysekera

A relay apparatus includes a plurality of reflection elements that applies independent phase shifts to an incoming wave, a communication circuitry that receives transmission point information from one or more transmission points, an element allocation circuitry, and a phase control circuitry. The element allocation circuitry determines the number of communication links to be established via the relay apparatus based on the transmission point information, determines the number of reflection elements to be allocated to each of the communication links, and determines a reflection element to be allocated to each of the communication links according to the number of the reflection elements. The phase control circuitry determines the phase weights so that a beam directed to a reception point being a communication destination of each communication link is generated by a reflection wave generated by each reflection element allocated to each of the communication links.

Relay control system, relay apparatus, and relay control method

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

A base station according to an embodiment of the present disclosure includes a generation unit () that generates a beacon including switching information () indicating whether to cooperatively use a frequency channel and a transmission unit () that transmits the beacon.

Base station, terminal apparatus, and wireless communication 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

Provided is a wireless communication system in which, based on a random access scheme, a transmission opportunity (TXOP) acquired by a wireless access point is granted to a wireless station when performing uplink data transmission from the wireless station to the wireless access point and the TXOP acquired by the wireless station is granted to the wireless access point when performing downlink data transmission from the wireless access point to the wireless station, the system includes a scheduling unit for TXOP granting determining one or more wireless stations having a quality of an uplink data transmission lower than a prescribed value as TXOP responders to which the wireless access point grants the TXOP, and determining one or more wireless stations having a quality of a downlink data transmission lower than the prescribed value as TXOP holders which grant the TXOP to the wireless access point.

Wireless communication system and wireless communication method

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

A relay system includes: one or more radiation units configured to form a beam in a predetermined direction by radiating radio waves from each of a plurality of elements; a detection unit configured to detect a physical environment on a radio wave propagation path that affects the beam formed by the radiation unit; a direction determination unit configured to determine a direction in which the radiation unit should form the beam based on the physical environment detected by the detection unit; a phase calculation unit configured to calculate a phase of radio wave to be radiated by each of the plurality of elements such that the radiation unit forms a beam in the direction determined by the direction determination unit; and a phase control unit configured to control the phase of the radio wave radiated by each of the plurality of elements based on the phase calculated.

Relay system, relay control device, relay method, and relay control program

A reflection direction control method includes an arrival direction estimation step of estimating an arrival direction of radio waves transmitted by a wireless terminal to one or more reflection units each including a plurality of reflection elements capable of dynamically changing phase characteristics when the radio wave is reflected, a phase control step of controlling a phase of a radio wave reflected by each of the plurality of reflection elements so that the reflection unit reflects, in a predetermined direction, the radio wave transmitted from the estimated arrival direction, and a switching step of switching between an antenna mode in which the reflection unit is caused to receive the radio wave of which the arrival direction is estimated and a reflection mode in which the reflection unit is caused to reflect the radio wave.

Reflection direction control method, reflection direction control system, reflection direction control device, and reflection direction control 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 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 LAN system where an interfering communication device is present around a base station device and a terminal device includes an interference control signal transmitter that transmits an interference control signal that causes the interfering communication device to wait for transmission, and an interference control signal management device that collects wireless environment information, sets wireless LAN communication between the base station device and the terminal device, which are protection targets, as protected communication, and causes the interference control signal transmitter to transmit an interference control signal that causes the interfering communication device to wait for transmission, and the interference control signal management device instructs the interference control signal transmitter to start transmitting the interference control signal when detecting a start of the protected communication and instructs the interference control signal transmitter to stop transmitting the interference control signal when detecting a stop of the protected communication.

Provide a wireless local area network (LAN) system, an interference control signal management device which are capable of limiting interference

A wireless communication system includes a sensing unit that detects an obstacle currently present between a transmitting station and a receiving station. There is an environment memory that stores information on a detection result of the sensing unit, an environment prediction unit that predicts a variation in a radio wave propagation environment between the transmitting station and the receiving station from the information stored in the environment memory. There is further a simulation calculation unit that simulates an environment in which a communication path between the receiving station and a reflector and a communication path between the transmitting station and the reflector are a line-of-sight environment on the basis of a prediction result of the environment prediction unit and calculates a control parameter of the reflector that achieves the environment. Further, a reflector control unit controls the reflector in accordance with the control parameter calculated by the simulation calculation unit.

Wireless communication method, wireless communication system, and wireless communication program

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 base station () according to an embodiment includes a data processing unit () and a wireless signal processing unit (). The data processing unit () generates a MAC frame. The MAC frame includes input data and an identification bit (CB). The identification bit (CB) indicates that data is extended broadcast data. The wireless signal processing unit () converts the MAC frame into a wireless signal to distribute the wireless signal.

Utilizing wireless distribution content

Growing community of inventors

Yokosuka, Japan

Yasushi Takatori