Fuzzy-Based Uplink Power Control in Forward Broadband Satellite Links

End-to-end performance of broadband satellite links operating at Ku band and above is studied in this paper. The problem of power control in terms of optimal power allocation and maximization of the total carrier-to-interference-and-noise ratio is considered. More specifically, the paper proposes the use of Fuzzy Inference Systems (FIS) to optimize power allocation in a dual-hop (end-to-end) satellite system, considering the general case of dual-polarized satellite links with transparent satellite transponder. The quality of the link is assessed through the FIS based on the predicted values of rain attenuation induced on the corresponding links and the interference-to-noise ratios. According to this estimation, the satellite hub-station increases or reduces the allocated uplink power. The proposed scheme's effectiveness is investigated in terms of carrier-to-noise plus depolarization plus interference ratio and power consumption for 30/20 GHz frequency in the uplink and the downlink respectively. A variety of conditions is considered regarding the rain attenuation values from 0 (no rain) to 30 dB and interference-to-noise ratio from -15 to 15 dB to both links. Finally, the scheme is compared to step-based power control algorithms, showing that it can significantly reduce the total consumed power.