Low complexity decoding for Raptor codes for hybrid-ARQ systems

Abstract

In this paper we present a low complexity decoding algorithm for Raptor codes which is used for incremental redundancy hybrid ARQ schemes. Encoding and decoding Raptor codes are the processes of making encoding symbols from the source symbols and the recovery of the source symbols from the received encoding symbols transmitted through an erasure channel, respectively. If the received encoding symbols are insufficient to recover the source symbols, additional encoding symbols are delivered and decoded with the previously received encoding symbols. We propose a low complexity decoding algorithm which efficiently combines the previously received encoding symbols and incremental encoding symbols. The proposed algorithm has excellent potential for realizing low power operation and higher throughput transmission due to its highly reduced computational complexity.