Nippon Telegraph and Telephone Corporation

Ntt Corporation

Riku Omiya

Yasushi Takatori

Tomoki Murakami

Tomoaki Ogawa

Takafumi Hayashi

Masashi Iwabuchi

Koichi Ishihara

Toshiro Nakahira

Hirantha Abeysekera

Shoko Shinohara

A reflection characteristic analysis device analyzes reflection characteristics of a reconfigurable intelligent surface (RIS: Reconfigurable Intelligent Surface). The reflection characteristic analysis device includes a ray trace calculation unit and an electromagnetic field analysis unit. The ray trace calculation unit calculates an incident angle of an electromagnetic wave incident on the reconfigurable intelligent surface by a ray-tracing method. The electromagnetic field analysis unit acquires the incident angle calculated by the ray trace calculation unit, and calculates, based on an electromagnetic field analysis, the reflection characteristics obtained when the electromagnetic wave enters the reconfigurable intelligent surface at the incident angle.

Reflection characteristic analysis device, reflection characteristic analysis method, and reflection characteristic analysis program

The reflection direction control system includes a plurality of reflection units each including a plurality of reflection elements, a position estimation unit for estimating a position of each of the wireless terminals on the basis of radio waves transmitted to the plurality of reflection parts wireless terminals, a direction estimation unit for estimating an incident direction of the radio waves transmitted by each of the wireless terminals to the reflection units, a phase calculation unit for calculating a phase of the radio waves to be reflected so that the reflection unit reflects the radio waves made incident in the direction estimated by the direction estimation unit in a predetermined direction, and a phase control unit for controlling the phase of the radio waves reflected by each of the plurality of reflection elements on the basis of the phase calculated by the phase calculation unit.

Reflection direction control system, reflection direction control device, reflection direction control method, and reflection direction control program

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 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 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 base station setting position calculation method includes a step Sfor assuming the setting area to be a rectangle, receiving an input of longitudinal and lateral lengths of a setting area and the number of wireless base stations to be set 's', and determining one or more candidates of a number of divisions 'd' of the setting area according to the number of wireless base stations 's', a step Sfor representing the number of divisions &#x201c;d&#x201d; in a division ratio x:y and selecting, for each number of divisions &#x201c;d&#x201d;, according to the longitudinal and lateral lengths of the setting area, a division ratio at which diagonal line lengths of divided areas are minimized, a step Sfor performing, for each number of divisions &#x201c;d&#x201d;, adjustment of a division pattern until a difference m between the number of divisions &#x201c;d&#x201d; and the number of wireless base stations &#x201c;s&#x201d; decreases to 0, a step Sfor calculating, for each number of divisions &#x201c;d&#x201d;, a sum of the diagonal line lengths of the divided areas and selecting the division pattern with which the sum is minimized, and a step Sfor setting the wireless base stations in the centers of gravity of the divided areas in the division pattern selected in step S

Wireless base station installation position calculation method and wireless base station installation position calculation device

A characteristic variable antenna configured to be able to select or switch antenna characteristics in accordance with a predetermined periodic variable timing, an RF unit configured to perform a reception process on a signal received by the characteristic variable antenna, an ADC unit configured to sample the analog signal input from the RF unit at a sampling period corresponding to the variable timing of the antenna characteristics of the characteristic variable antenna, a signal dividing unit configured to divide the digital signal input from the ADC unit into different digital signals in accordance with the antenna characteristics and output the divided different digital signals, a MIMO-OFDM demodulation unit configured to receive inputs of the different digital signals divided by the signal dividing unit and perform a demodulation process of predetermined MIMO-OFDM, and a control unit configured to periodically select or switch the antenna characteristics of the characteristic variable antenna in accordance with the sampling period of the ADC unit are included.

Growing community of inventors

Musashino, Japan

Riku Omiya