TIME DELAY DIVERSITY/SATELLITE DIVERSITY (TDD/Sat-D) SYSTEM USING TWO EARTH STATIONS OF CLOSE RANGE

摘要

PROBLEM TO BE SOLVED: To obtain a sufficient diversity effect in the Sat-D system for avoiding line disconnection due to rainfall by using two satellite signals, in the fixed satellite services using Ku, Ka bands.;SOLUTION: Availability ratio of line is enhanced by using two earth stations separated about 3-5 km, and using a diversity mode for switching to other earth station when the rainfall attenuation of one earth station increases. Furthermore, when the rainfall attenuation increases and the line is disconnected, switching is made to the TDD/Sat-D system where a repeater transmitting a delayed signal is operated on two satellites and a signal is transmitted with as much delay as a delay amount (t1-t2), and received via a delay circuit in the earth station. Degradation in the availability ratio of line is improved by demodulating a signal of highest signal strength.;COPYRIGHT: (C)2013,JPO&INPIT