Joint network coding and OFDMA based MAC-layer in PLC networks

Due to the existing frequency-selectivity in PLC channels, data transmission over long distance can exhibit serious difficulties in PLC systems. In order to reduce the attenuation effect for long transmission distances between two nodes (a transmitter and a receiver), we use a relay in PLC systems. Many considerations are taken into account in this system such as the variation of the distances between the transmitter and the relay and between the relay and the receiver. We highlight in this paper how the use of network coding makes it possible to increase the transmitted data rate in an OFDMA based MAC layer. In order to maximize the total data rate, we propose low-complexity subcarrier assignment algorithms for the uplink and downlink of OFDMA based PLC networks. Simulation results are given to support our claims and highlight the performance gain that can be obtained for PLC systems in terms in enhancement of the transmission rate.