Incremental Network Coding in Cooperative Transmission Wireless Networks

For block-fading Rayleigh channels, this work considers a network coding approach to cooperative transmission. The network under consideration consists of two sources, S and P, that transmit to a common destination, D. Using half-duplex channels, S and P transmit their packets to D; they also overhear each other´s transmission. Then both sources cooperate by transmitting a network-coded packet, which is used at D as incrementally redundant information. We first analyze outage probability and show that this scheme achieves full diversity when good quality inter-source channels exist; the result is also verified through simulation. Then, using the outage result we investigate the ´optimal´ rate and energy allocations that minimize the outage probability. The results show that the outage-based performance is more sensitive to the energy allocation than to the rate allocation.