Hitachi, Ltd.

Godo Kaisha IP Bridge 1

May Takada

Satoshi Tamaki

Tsutomu Yamada

Kenzaburo Fujishima

Shiro Mazawa

Katsuhiko Tsunehara

Yosuke Takahashi

Rintaro Katayama

Yoshihito Sato

Koki Uwano

Go Ono

Masaki Yamada

Mikio Kuwahara

Masayuki Miyazaki

Shinya Sasaki

Yuji Ogata

Noritaka Matsumoto

Toshiyuki Odaka

Tomonori Yamamoto

Shoji Yunoki

Nobuyuki Muranaka

Yoshinori Okura

Kazuya Shimoyama

Shigeyuki Ejiri

It is provided a wireless communication system comprising base stations that transmit data to a terminal with cooperation by the base stations. The terminal communicates with the base stations. The terminal periodically transmits, to one of the base stations, information necessary for data transmission from a single base station out of the base stations. Each of the base stations determines whether the terminal needs data transmission through a cooperation among the base stations, and transmits a cooperation information transmission instruction to the terminal, which includes information necessary to execute the data transmission in order to cooperate among the base stations in the case where it is determined that the terminal needs the data transmission through the cooperation among the base stations. The terminal transmits the cooperation information to the base stations in a case of receiving the cooperation information transmission instruction.

Base station and wireless communication system

A multistage relay communication systemincludes a trunk networkand branch networks(), each of which includes one or more communication apparatuses. The communication apparatuscan switch between a trunk mode to operate in the trunk networkand a branch mode to operate in the branch network. In the trunk network, the communication apparatuscarries out fixing of a communication path and redundancy of data based on a path table in order to achieve real-timeness and a data arrival rate. Meanwhile, in the branch network, when a communication failure occurs, the communication apparatusautonomously searches for a communication path and constructs a path table, in order to at least secure a data arrival rate even if real-timeness is impaired within an allowable range.

Relay communication apparatus and multistage relay communication system

Provided is a monitoring system which can perform priority control in accordance with the wideband limitation. A priority/filter type selection processing unit () of a network interconnection device (), which connects a local network () and a wide area network (), selects a transmission data selection processing unit () on the basis of the priority level definitions of a transmission data in accordance with an event status, and a data compression method in association with the event status and the wide area network communication status, and selects and controls a filtering processing unit (). As a consequence, the communication bandwidth in a wide area network is reduced.

Monitoring system, device, and method

In a wireless communications system operating according to CDMA or the like, when one terminal simultaneously performs communication using multiple wireless resources (e.g., multiple carriers), there was a problem that when it was attempted to guarantee network mobility by the same soft handoff system as in the case where communication was performed using only one wireless resource, efficiency suffered from the viewpoint of network forwarding load, processing load and wireless resource occupancy time. Soft handoff termination is judged and soft handoff is forcibly terminated according to whether or not the data rate obtained for all resources on the network side satisfies a requested rate, based on a reception state notification from a terminal concerning wireless resources. By performing this processing, the soft handoff period is shortened, sufficient received strength in the terminal is maintained and terminal mobility is guaranteed, while at the same time network forwarding load, terminal processing load and wireless resource occupancy time are suppressed to the absolute minimum.

Control node in a communication system using multiple wireless resources during a soft handoff

A plurality of wireless communication methods are combined, networks to be used are dynamically selected by evaluating each network quality, and a packet format is changed adaptively to realize necessary reliability. The wireless communication apparatus has a network interface, a data interface, a quality interface, an allocation control part, a quality database, a quality update part, communication units and antennas. The wireless communication apparatus receives data and a requested quality from an application apparatus, selects the communication unit and communication method suitable for the requested quality, and transmits the data and requested quality. The communication unit receives a communication quality of the communication partner, and the quality update part updates the communication quality state in the quality database.

Wireless communication apparatus and wireless communication method

A radio communications system includes at least one terminal communication unit having one antenna that conducts a radio communication with a plurality of terminals; and at least one baseband modem that generates and decrypts a data signal, a cell being configured by at least one of the antenna, wherein the baseband modem divides a radio frequency band used for the radio communication into two or more subbands, generates and decrypts the data signal specific to each of the divided subbands, and allocates the data signal specific to the subband to the terminal communication unit, and wherein the terminal communication unit receives the data signal specific to the subband generated by the baseband modem, and forms the cell of each the subband by the data signal specific to the received subband.

Radio communications system

Provided is a wireless communication system, comprising: a wireless communication apparatus which performs adaptive modulation for changing a modulation method and an encoding rate of a data channel, and transmits/receives a signal via MIMO multiplexing. The control information comprises first control information to be used for a MIMO stream separation process and second control information not to be used for the MIMO stream separation process. The selections in the second control information are changed corresponding to selected first control information. The wireless communication apparatus determines the first control information at an update timing of the first control information by referring to the first control information table, determine selections of the second control information based on the determined first control information, and select one of the selections of the second control information among the determined selections of the second control information at an update timing of the second control information.

Wireless communication system, apparatus and method thereof

In a cellular radio communication system, a base station or a mobile station has a TA (Time Alignment)-range-out detection function, so that when a TA-range-out state that is unable to compensate with a guard interval is detected, the transmission condition of an uplink signal at the mobile station is changed by the mobile station autonomously or by the base station and the mobile station cooperatively.

Base station and mobile station for OFDMA cellular system

Communication system using multiple wireless resources during a soft handoff

Growing community of inventors

Koganei, Japan

May Takada