Relay selection in network coded communications with power control

This paper is concerned with the computationally efficient selection of relays and assignment of transmit power values in wireless networks deploying cooperating nodes. The objective is to minimize the transmitted power required to exchange the data between two nodes. Specifically, the design of routing protocols with multiple store-and-forward relays along a data path is proposed for multiple unicast sessions in a network with randomly distributed nodes. The protocols are based on the knowledge of interdistances between nodes and, by adapting the transmission power, they control the topology to achieve the minimized total energy in networks with mesh type connectivity. In addition, the benefits of network coding are exploited for underlying networks with dynamic power allocations. Geometric ideas and abstractions are used to demonstrate that nodes which are closest to equi-spaced points distributed along the line of communication between a source and destination pair are the most energy efficient choices for relays. An analysis of the energy efficiency of the conventional store-and-forward and network coding based relaying schemes under different propagation conditions and for various node densities, with potential theoretical improvements corroborated through simulations, are also provided.