An Energy-Efficiency Comparison of RLNC and ARQ in the Presence of FEC

We consider the problem of multicasting from a single source to multiple destinations over an erasure channel model. We are interested in energy-efficient communication. Our performance metric is the number of bits that the source delivers successfully to all destinations per joule of the overall energy spent. We compare the performance of Random Linear Network Coding (RLNC) and Automatic Repeat reQuest (ARQ) with respect to the above performance metric in the presence and absence of Forward Error Correction (FEC). Our numerical results illustrate that RLNC is more energy-efficient than ARQ when the links are highly unreliable. However, as the reliability protection provided to the links through FEC increases the energy-efficiency performance of RLNC deteriorates and it becomes suboptimal compared to ARQ methods.