Apparatus and method for controlling forward error correction encoding in a very small aperture terminal

A system for controlling the forward error correcting rate of a VSAT comprising:

• a hub earth station having an outroute transmitter for forwarding digital data modulated on an outroute carrier signal;
• a transmit power control for changing the level of power being transmitted by said hub earth station;
• an encoder means for generating from said level a data packet representing said level and for combining said packet with said digital data;
• a VSAT earth station for receiving said outroute carrier signal;
• a demodulator at said VSAT earth station for removing said packet from said digital data;
• an inroute transmitter for forwarding digital data from said VSAT earth station to said hub station over an inroute carrier;
• a forward error correcting encoder for encoding said VSAT digital data at multiple rates selectable by a control signal;
• and
• means for supplying said control signal to said forward error correcting encoder based on said data packet.

A VSAT earth station having an FEC encoding rate which varies in accordance with propagation conditions comprising:

• a radio frequency converter for providing an IF signal from a received outroute signal transmitted by a hub earth station via a satellite transponder, and providing an inroute radio frequency carrier signal for transmitting a data signal to said hub earth station;
• an outroute IF signal demodulator connected to receive said IF signal and to remove digital data packets contained in said IF signal;
• a baseband signal processor connected to receive said digital data packet from said outroute IF signal demodulator and to produce inroute digital data packets for transmission to said hub station;
• an FEC encoder for encoding said inroute digital data packets at a selectable FEC rate;
• means for estimating propagation conditions and supplying a signal for selecting said FEC rate based on said propagation conditions;
• and
• an inroute modulator for receiving said encoded inroute digital data packets and modulating said inroute radio frequency carrier with said encoded inroute digital data packets.