On the Performance of Distributed LT Codes

In this paper we extend previous results on distributed LT codes and focus on the frame erasure rate performance of the corresponding block codes with fixed rate. Specifically, we address modified LT (MLT) codes which resemble LT codes in both structure and performance. First, an MLT code construction scheme for four sources communicating with a single sink via a common relay is presented. Then, for the fixed rate case and erasure channels at both source-relay and relay-sink links, simulation results are given for the frame erasure rate versus the corresponding erasure probabilities. We observe that MLT codes strongly outperform a scheme where an LT block code for every source is separately transmitted over the relay-sink erasure channel. This is due to the increased codeword length for the MLT code-based schemes.