On-line fountain codes for semi-random loss channels

A fountain coding framework is proposed that endows receivers with the ability to monitor and control the decoding progress given the instantaneous network conditions. These online features allow an optimal recovery from losses manifested by adversarial or other not purely random processes. A uni-partite graph structure and accompanying algorithms are used to efficiently calculate optimal instantaneous degrees. Using analysis of random-graph processes, the average overhead of a simplified scheme is shown to be upper bounded by 0.236, significantly lower than any known on-line fountain scheme.