Network control system for controlling relative errors between network nodes

摘要

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.