Hitachi Denshi Kabushiki Kaisha

Hitachi, Ltd.

Other

Hitachi Communication Technologies, Ltd.

Yoshito Ohta

Nobukazu Doi

Masayuki Ariyoshi

Tesshin Shiga

In CDMA communications, a base station detects a difference between a reference phase of a spreading code and a phase of a received signal of each terminal station, and feeds a phase jump signal PJ-i representative of the phase difference back to each terminal station. After timing acquisition, the reception operation is performed using the reference phase, and a shift amount between the phase of a received signal and the reference phase is fed back to each terminal station as phase synchronization control information PC-i. Each terminal station coarsely adjusts the phase of the spreading code in accordance with the phase jump signal PJ-i, and thereafter finely adjusts the phase of its transmitting signal in accordance with the phase synchronization control information PC-i. It is therefore possible to synchronize the phases of the signals transmitted from terminal stations and received at the base station. Accordingly, an orthogonal code is used for spreading on the reverse links.

CDMA communication system and method

CDMA Communication system and method

A communication system having a central station and a plurality of terminal stations coupled through a bi-directional communication path such that the terminals communicate with each other through the central station, has dedicated communication channels assigned to couple a terminal station with another terminal station and common communication channels simultaneously assigned to the plurality of terminal stations in a multiplexing manner. The central station has a control unit for selecting one from the dedicated communication channels and the common communication channels in response to a communication request from a terminal station.

Communication system having at least two types of communication channels

Growing community of inventors

Tokorozawa, Japan

Yoshito Ohta