Improved non-uniform selecting encoding algorithm for fountain codes with short code-length

Fountain codes are rateless and they can transmit information reliably and efficiently without knowing a priori knowledge of the channel. However, the performance of fountain codes decreases dramatically when code length is shortened. In order to improve the transmission reliability of fountain codes with short code-length, the adjustment among sets non-uniform selecting (ASNS) encoding algorithm is proposed. In ASNS algorithm, the robust soliton degree (RSD) distribution is modified to avoid source symbols imperfect coverage, and some operations on source symbols collections are done to change the probability of source symbols involved in encoding. Simulation consequences show that, under different channel conditions, the proposed ASNS algorithm can achieve much lower decoding failure rate than traditional uniform selecting algorithm and the doping and non-uniform selecting (DNS) algorithm with code-length at 100 and 500.