Nippon Telegraph and Telephone Corporation

Nec Corporation

Nippon Telegraph Telephone Corporation

Tomoki Murakami

Koichi Ishihara

Yasushi Takatori

Toshiro Nakahira

Hirantha Abeysekera

Takafumi Hayashi

Masato Mizoguchi

Riichi Kudo

Takeo Ichikawa

Kazutaka Hara

Tomohiro Taniguchi

Ryota Shiina

Tomoaki Ogawa

Riku Omiya

Shinya Tamaki

Masashi Iwabuchi

Mamoru Akimoto

Munehiro Matsui

Hiroshi Kurihara

Kentaro Nishimori

Hiroshi Sakamoto

Takefumi Hiraguri

Masamichi Hosoda

Tadashi Mori

Yoshiaki Kisaka

Yusuke Asai

Masaru Miyamoto

Shinya Otsuki

Keisuke Wakao

Akiyoshi Inoki

Masahito Tomizawa

Etsushi Yamazaki

Seiji Okamoto

Hayato Fukuzono

Shoko Shinohara

Yosuke Takeuchi

Kengo Horikoshi

Tomoyuki Yamada

Tomoaki Kumagai

Tadao Nakagawa

Makoto Umeuchi

Tomoyoshi Kataoka

Yasuhiko Sakaguchi

Hisatoshi Kasahara

Yosuke Okamura

Junichiro Tamamatsu

Keisuke Daikohara

Atsushi Hashiguchi

Hiroki Oyama

Yoshiki Shioji

Tadayuki Ohno

Yasushi Hanakago

Communication is performed between a radio base station and a radio terminal via a reflector. The radio base station transmits a measurement signal including a beam ID of a transmission beam for measuring communication quality between the radio base station and the radio terminal. The reflector reflects the measurement signal incident on the reflector in multiple reflection directions to generate multiple reflected measurement signals. Moreover, the reflector modulates the incident measurement signal during reflection to add information about a reflection direction ID being different for each of the multiple reflection directions to each of the multiple reflected measurement signals. The radio terminal demodulates a reflected measurement signal received from the reflector to acquire the reflection direction ID and the beam ID. The radio terminal then evaluates the communication quality for each combination of the beam ID and the reflection direction ID based on reception state of the received reflected measurement signal.

Radio communication method, radio communication system, radio base station, and reflector

A passive relay device () relays radio communication between the inside of a radio wave shielding structure () and the outside of the radio wave shielding the structure (), and the device includes an internal antenna () which connects with the inside, an external antenna () which connects with the outside, and a connection part () which connects the internal antenna () and the external antenna ().

Passive relay device and passive relay 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 wireless transmission device transmits a radio signal with a plurality of beam patterns and outputs transmission beam identifiers corresponding to the beam patterns to an object detection device, a wireless reception device receives the radio signal transmitted by the wireless transmission device with a plurality of beam patterns, measures received signal strength for each of the beam patterns and outputs reception beam identifiers and the received signal strength to the object detection device, and the object detection device detects an object within a detection area on the basis of the transmission beam identifiers, the reception beam identifiers and the received signal strength. This enables device-free object detection by utilizing a beamforming function, so that it is possible to achieve high detection accuracy while preventing increase in cost.

Object detection method, object detection device, and object detection system

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

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 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 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 radio terminal station device includes a communication unit, an information acquisition unit, a threshold calculation unit, a detection unit, and a system selection unit. The communication unit selects any one of a plurality of different communication systems and performs a radio communication. The information acquisition unit acquires information including a communication state of the radio terminal station device and at least communication states of other radio terminal station devices. The threshold calculation unit calculates a threshold value for detecting deterioration of the communication state of the radio terminal station device. The detection unit detects the deterioration of the communication state of a communication system used by the radio terminal station device. The system selection unit selects an optimal communication system from among the communication systems used by the other radio terminal station devices when the deterioration of the communication state of the communication system of the radio terminal station device is detected. Thus, it is possible to maintain favorable communication quality.

Wireless terminal station device, management station device, wireless communication system and wireless communication method

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

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 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

Tomoki Murakami