Distributed Raptor Coding for Erasure Channels: Partially and Fully Coded Cooperation

TL;DR

This paper introduces new rateless coded cooperation schemes based on Raptor codes for multi-user wireless systems facing erasures, optimizing throughput with novel degree distributions.

Contribution

It proposes fully and partially coded cooperation strategies using Raptor codes, with optimized degree distributions for erasure channels, improving system throughput.

Findings

Optimized degree distributions significantly increase throughput.

Partially coded cooperation outperforms fully coded cooperation.

Schemes are effective without channel state information.

Abstract

In this paper, we propose a new rateless coded cooperation scheme for a general multi-user cooperative wireless system. We develop cooperation methods based on Raptor codes with the assumption that the channels face erasure with specific erasure probabilities and transmitters have no channel state information. A fully coded cooperation (FCC) and a partially coded cooperation (PCC) strategy are developed to maximize the average system throughput. Both PCC and FCC schemes have been analyzed through AND-OR tree analysis and a linear programming optimization problem is then formulated to find the optimum degree distribution for each scheme. Simulation results show that optimized degree distributions can bring considerable throughput gains compared to existing degree distributions which are designed for point-to-point binary erasure channels. It is also shown that the PCC scheme outperforms the FCC scheme in terms of average system throughput.