Network Coding-based Relay for IEEE 802.16j multi-hop relay network

IEEE 802.16j is to enable the operation of multi-hop Relay Stations (RS). It aims to enhance the coverage, per user throughput and system capacity of IEEE 802.16e. However, the Mobile Stations (MSs) which connect to the RS are suffering from exponentially throughput degradation and end-to-end delay increase in congested network. As the number of RS hops increases, so does the degradation and the delay growth, especially on over 3 hops scenarios. This paper proposes a Network Coding-based Relay scheme for multi-hop relay networks, called NC-based Relay. It allows RSs to combine multiple wireless backhaul transmissions into single transmission using network coding technique. We also propose an improved OFDMA frame structure design for multi-hop relay network, which provides higher utilization for the relay zone by reorganizing the RSs transmission sequence. The analysis and simulation results confirm that the proposed scheme can enhance the throughput gain up to 140%, and reduce the end-to-end delay by up to 83%.