COMMUNICATION POWER CONTROL SYSTEM FOR USER TERMINAL VIA SATELLITE

摘要

PROBLEM TO BE SOLVED: To attain autonomous control of a user terminal via a satellite and also to reduce the system complicacy by generating a power control command in a space segment based on the difference of intensity between a receiving signal and the desired one and sending the control command to the user terminal to control the transmitting power of uplinks. SOLUTION: A ground user terminal 5 transmits the uplink signals to the non-geostationary orbit satellites (NGSO) SAT-1 and SAT-2 via the uplinks 31a and 31b respectively. Both SAT-1 and SAT-2 generate the signal intensity information based on the error rate of a CDMA system and send them to geostationary orbit satellite 3 via the links 33a and 33b. When the signal intensity of the SAT-1 is reduced due to an obstacle like a rainfall cell 33, etc., the satellite 3 sends the information on difference of signal intensity information to the terminal 5 via the links 34a and 34b and the downlinks 32a and 32b to control the transmitting power.