Patent ID: 6272340
Filing Date: 2001-08-07
Classification: H04B

Abstract:
A load shedding method to enhance uplink margin between a terrestrial terminal and a satellite in a satellite based communications system, said load shedding method comprising:generating at the terrestrial terminal a first signal having a first carrier channel;generating at the terrestrial terminal a second signal having a second carrier channel;transmitting from the terrestrial terminal to the satellite a cumulative uplink signal formed by the first signal having the first carrier channel and the second signal having the second carrier channel;determining by a terminal control unit in the terrestrial terminal a transmit power level P.sub.T of the cumulative uplink signal formed by the first signal and the second signal transmitted from the terrestrial terminal;determining a received power level P.sub.R of the cumulative uplink signal formed by the first signal and the second signal received at the satellite;transmitting a power control report from the satellite to the terrestrial terminal that identifies the received power level P.sub.R of the cumulative uplink signal formed by the first signal and the second signal received at the satellite;determining an attenuation level P.sub.T -P.sub.R by the terminal control unit in the terrestrial terminal;terminating transmission of the second signal having the second carrier channel upon instruction by the terminal control unit when the attenuation level P.sub.T -P.sub.R of the cumulative uplink signal formed by the first signal and the second signal transmitted from the terrestrial terminal exceeds a first threshold; andresuming transmission of the second signal having the second carrier channel upon instruction by the terminal control unit when the attenuation level P.sub.T -P.sub.R is less than a second threshold, wherein the first threshold is greater than the second threshold to provide a level of hysteresis.