Design of a selective FEC subsystem to counteract rain fading in Ku-band TDMA systems

A major concern in satellite communications systems operating at frequencies above 10 GHz (e.g., Ku band) is the performance degradation caused by rain fading. In this paper, an effective method for combatting this phenomenon in TDMA systems is described. This method is based on the application of additional FEC coding protection on a dynamic basis to faded traffic terminals. Selective (adaptive) forward error correction (S-FEC) coding permits the fixed fade margins used by the network earth-stations to be substantially reduced, while a desired outage probability is maintained. This paper deals primarily with the implementation of the monitoring and control subsystems required in a practical S-FEC network.