Network coded information raining over high-speed rail through IEEE 802.16j

Two-hop network architectures, with wireline and 802.16a backhauls, respectively, and 802.11 repeaters/relays, were proposed for high-speed rail. The resulting infrastructure cost in the former, and complexity of dual mode wireless relays in the latter, urge the need for more technically and economically efficient solutions. In this paper, we first propose a two-hop wireless network architecture for high-speed rail employing 802.16j. Due to its backward compatibility with 802.16e, the use of 802.16j not only mitigates the restrictions of the previous two-hop heterogeneous solutions but also allows a third direct communication link from the base-station to the trains, thus providing opportunities for throughput improvements. We then propose a network coded downlink transmission scheme over the proposed network architecture to both eliminate the undesirable ARQ overhead in high-speed rail communications and better exploit relay diversity. We refer to our proposed scheme as network coded information raining. Simulation results show the merits of our proposed solutions.