Cooperative Transmission in a Wireless Relay Network based on Flow Management

In this paper, a cooperative transmission design for a general multi-node half-duplex wireless relay network is presented. It is assumed that the nodes operate in half-duplex mode and that channel information is available at the nodes. The proposed design involves solving a convex flow optimization problem on a graph that models the relay network. A much simpler generalized-link selection protocol based on the above design is also presented. Both the proposed flow-optimized protocol and the generalized-link selection protocol are shown to achieve the optimal diversity-multiplexing tradeoff (DMT) for the relay network. Moreover, simulation results are presented to quantify the gap between the performances of the proposed protocols and that of a max-flow-min-cut type bound, in terms of outage probability.