Fujitsu Corporation

Tetsuyoshi Takenaka

Hideto Furukawa

Nobutsugu Fujino

Takeshi Inoue

Atsushi Yamashita

Satoru Chikuma

Yoshiharu Tajima

Kazuo Kawabata

Tadashi Nakamura

Travel velocity detecting apparatus in mobile communication system

A network control system for eliminating a relative error among control signals transmitted from nodes provided in radio zones respectively, a mobil station moving among the radio zones, each of the nodes comprising: a relative error detecting unit for detecting a relative error between an after-controlled transmitting control signal to be transmitted to adjacent nodes and a received control signal from an adjacent node; and a control unit for controlling a before-controlled transmitting control signal in such a way that the relative error becomes zero so as to output the after-controlled transmitting control signal.

Network control system for controlling relative errors between network

A network control system for controlling a plurality of nodes respectively corresponding to, and provided in, a plurality of radio zones. Each node has a corresponding base station, where a mobil station travels among the plurality of radio zones and communicates with the base station of a respective node when travelling in a radio zone corresponding to the respective node. Each base station transmits a transmission signal for the corresponding node to adjacent nodes, receives transmission signals transmitted from the base stations of adjacent nodes and spatially filters the received transmission signals. Each base station includes (a) a notification unit notifying the base stations of adjacent nodes of transmission timing information of the transmission signal of its own node, and (b) a correction unit receiving transmission timing information from the base stations of adjacent nodes indicating the timing of the transmission signals of the adjacent nodes, and correcting the timing of the transmission signal of its own node to minimize a difference between the timing of the transmission signal of its own node and the timing of the spatially filtered transmission signals received from the base stations of the adjacent nodes.

A network control system for controlling a plurality of nodes respectively corresponding to, and provided in, a plurality of radio zones. Each node has a corresponding base station. A mobil station travels among the plurality of radio zones and communicates with the base station of a respective node when travelling in a radio zone corresponding to the respective node. Each base station transmits a transmission signal to adjacent nodes and receives transmission signals transmitted from the base stations of adjacent nodes. Each base station includes (a) a reception automatic frequency control unit receiving the transmission signals transmitted by base stations of adjacent nodes, and performing an automatic frequency control operation for each received transmission signal, (b) a frequency error detection unit detecting a frequency error between the automatic frequency controlled transmission signals and a frequency obtained by adding a nominal frequency gap between base stations to the transmission frequency of the transmission signal of the node corresponding to the frequency error detection unit, (c) an averaging unit spatially filtering the frequency errors to produce a spatial mean value, and (d) a transmission frequency control unit controlling the transmission frequency of the node corresponding to the transmission frequency control unit in accordance with the spatial mean value, to substantially eliminate the frequency errors.

There is provided a method and an apparatus for assigning a radio channel between base and mobile stations in a mobile communication system, which provide advantages of first available and reuse partitioning systems and do not cause as great a proportional increase in a processing amount as an ARP system. A radio zone is divided into a number of regions having the same area which is equal to channel number N, usable in an entire system by concentric circles centering on a base station 12. Channels 1 to N.sub.s are allotted to the respective regions. Upon the issuance of a channel assignment request, a channel corresponding to the region where the mobile station is located or its neighboring channels is assigned preferentially.

Growing community of inventors

Kawasaki, Japan

Tetsuyoshi Takenaka