Optimum power allocation for Amplify-and-Forward cooperation strategy in WSN

Energy is an extremely limited resource in wireless sensor networks (WSNs). Thereby, various power management strategies have been proposed to reduce the quantity of consumed energy. In this article, the aim of our approach is to provide the optimal transmission power in order to maximize the network lifetime using the orthogonal channels and taking into account a Symbol Error Rate (SER) constraint at the Fusion Center (FC). In order to analyze our approach, we will first study the case where the information passes by a single relay to reach the destination creating several boughs. We call this case “virtual mimo with a single relay”. Second, we will consider a specific case with a single bough and several relays and then generalize a global case with several relays and several boughs. In addition, we suppose that a Maximum Ratio Combining (MRC) is used by the receiver as a detector, and Amplify and Forward (AF) is used as a relaying strategy where the channel gain coefficients are known. Simulation results show the viability of our approach.