An Energy-Efficient Distributed Relay Selection and Power Allocation Optimization Scheme over Wireless Cooperative Networks

In this paper, we propose a distributed joint relay selection and power allocation scheme in wireless multi-hop cooperative networks, taking both instantaneous channel state information (CSI) and relay nodes' residual energy into consideration. Specifically, we formulate the cooperative relaying network as a restless bandit system, which has been successfully applied in stochastic control and operations research problems. The first-order finite-state Markov chain is used to characterize the time-varying channel and residual energy state transitions. With this stochastic optimization formulation, the optimal policy for joint relay selection and power allocation has indexability property that dramatically reduces the computation and implementation complexity. Analytical and simulation results demonstrate that the proposed scheme can efficiently enhance the expected system reward, while guaranteeing a good tradeoff between achievable date rate and average network lifetime.