Path diversity gain with network coding and multipath transmission in wireless mesh networks

In this paper we investigate the performance that can be achieved by exploiting path diversity through multipath forwarding together with redundancy through linear network coding, in wireless mesh networks with directional links. A key contribution of the paper is to capture the tradeoff between packet delay and throughput achieved by combining multipath forwarding and network coding, and compare this tradeoff with that of simple multipath routing where different flows follow different paths, the transmission of multiple copies of packets over multiple paths, and single path routing. The analytical framework considers the case of end-to-end retransmission for achieving reliability, and is generalized for an arbitrary number of paths and hops. We also derive the minimum and maximum number of coded packets that are needed at the receiver to retrieve all packets sent by the sender; this can be used to obtain a lower and upper bound for the delay in the case of linear network coding with multipath forwarding.