Efficient encoding of systematic Raptor codes based on operation lists for known block lengths

Abstract

Raptor codes can provide good error correction capability and efficient encoding and decoding rates. Its fountain code property is effective in avoiding packet retransmission for both unicast and multicast service delivery. Hence, there are many wireless and broadband applications adopting it such as mobile multimedia broadcasting and broadband IPTV systems. In this paper, we present an efficient systematic Raptor codes encoder based on operation lists for known block lengths. For a Raptor codes application that can frequently use one or several fixed block lengths (i.e., the number of source symbols in a source block), we could produce the corresponding operation lists in advance and use it to generate the encoding symbols more efficiently. We first introduce the basic architecture of the proposed Raptor encoder, and then describes the details about how to generate operation lists and Raptor intermediate symbols. The simulation results show that our encoder is at least two times faster than the conventional Raptor codes encoder which is adopted by 3GPP and DVB-H.