Hybrid Protocols for Relay-Assisted Non-Orthogonal Multiple Access in Power Line Communications

We study the outage probability performance of hybrid protocols in relay-assisted, non-orthogonal multiple access (NOMA)-based power line communication. In particular, we consider two networks with source, relay and destination nodes, namely, cooperative relaying NOMA (CR NOMA) and single-stage NOMA (SS NOMA). We derive closed-form expressions for the outage probabilities of three hybrid relaying techniques, namely, hybrid decode- and amplify-and-forward (HDAF), incremental HDAF (IHADF) and IHDAF with maximal ratio combining (MRC) protocols. The HDAF protocol overcomes the limitations of decode-and-forward (DF) and amplify-and-forward (AF) protocols, by combining the advantages of both. In IHDAF protocol, the advantage of successful decoding at the receiver is exploited using the direct link between source and destination nodes, with the added benefit due to HDAF. Through an extensive simulation study, we (a) validate our analysis, (b) show that IHDAF-MRC outperforms IHDAF, HDAF, DF and AF, and (c) CR NOMA outperforms SS NOMA when IHDAF-MRC scheme is employed.