Fade countermeasure using signal degradation estimation for demand-assignment satellite systems

This paper describes a complete fade countermeasure system, designed for thin route user-oriented and fully meshed satellite networks. The signal degradation due to the residual up-link attenuation after up-power control intervention, plus the down-link attenuation, is compensated for by varying the FEC coding and bit rates of the data. Down and up-link signal degradations are evaluated separately: the former by collecting statistics of quantized levels of the demodulated PSK signal, and the latter by using a narrow band signal level estimator. Measurement times are optimized using a model to evaluate the scintillation variance. The performance evaluation of the whole system in the presence of additive white Gaussian noise (AWGN), shows that very small link power margins can be adopted.