Nec Corporation

Nippon Electric Co., Ltd.

Yasuhisa Shimada

Satoru Ohno

Satoru Ono

Goro Oshima

A transmitting power control system is disclosed wherein a master earth station sends a pilot signal to a satellite which retransmits it to the master station as well as to slave earth stations. A beacon signal is also sent from the satellite to the master station which compares it with the received pilot signal and controls its own transmission power level according to the result of the comparison so that the power level of retransmitted pilot signal is maintained constant. A warning signal is sent from the master station to all the slave stations when the received pilot signal decreases below a prescribed value corresponding to a predetermined precipitation. Each slave station receives the pilot signal from the satellite and controls its own transmission power level according to the received pilot signal. A disabling circuit is provided in each slave station to disable the power control function of the own station in response to the warning signal to prevent the satellite from being overloaded by the information signals transmitted from the slave earth stations.

Precipitation loss compensation and disablement for avoidance of

In an earth station (11), an amplifier (15) amplifies a pilot information signal with a variable gain. An up link pilot is thereby transmitted with a controllable transmission power. A beacon receiver (28) detects a level or C/N with which a beacon signal emitted by a satellite reaches the station. A pilot receiver (33) detects a level or C/N for a down link pilot radiated by the satellite in response to the up link pilot. A controller (37) controls the gain to keep a ratio between the levels or C/N's constant. For keeping a similar ratio constant, another station may transmit a transmission signal with a likewise controllable transmission power and receive the down link pilot together with a return signal radiated by the satellite in response to the transmission signal. Still another station may control a similarly controllable transmission power in consideration of an up link attenuation which is estimated from the level or C/N of the down link pilot. One of up link signals may be substituted for the up link pilot with that one of down link signals used for the down link pilot which is radiated by the satellite in response to that one up link signal. Up link signals transmitted with the power so controlled, are radiated by the satellite as down link signals with a substantially constant EIRP despite an attenuation which might be caused to the up link signals by rain or mist.

Growing community of inventors

Tokyo, Japan

Yasuhisa Shimada