Flooding-assisted informed dynamic scheduling for rateless codes

Abstract

As part of the tradeoff between error performance, decoding complexity and the overhead of rateless codes, the combination of incremental decoding (ID) and informed dynamic scheduling (IDS), known as IDIDS (incremental decoding with informed dynamic scheduling), is an attractive solution in binary symmetric channels (BSC). However, applying IDIDS in the AWGN (additive white Gaussian noise) channel may cause a degradation in BER performance, since the incrementally received symbols from the AWGN channel may not be immediately utilized in the decoding process directed by IDS. In addition, a stopping criterion combined with IDS may cause the current decoding attempt to terminate too early, and the channel information contained in the originally received codeword will not be used efficiently. In this paper, a dynamic decoding schedule strategy is proposed. In the proposed decoder, the new received symbols can be immediately utilized in the decoding process. For Luby transform (LT) codes and Raptor codes over the AWGN channel, the proposed algorithm provides a more balanced tradeoff. In the case of Raptor codes, the BER performance is obviously improved.