Performance analysis of energy efficient cooperations in WSNs over frequency-selective channels

Abstract

Energy efficient cooperations in wireless sensor networks (WSNs) subject to flat fading channels have attracted a considerable amount of attention recently. However, wireless channels of WSNs operating in indoor environments are supposed to have a frequency-selective nature, yet a comprehensive analysis of cooperative communications in these WSNs practically does not exist. Therefore, this paper has studied energy efficient cooperative communications over frequency-selective fading channels. Investigations of the energy efficient decode-and-forward and the adaptive decode-and-forward cooperations are provided in terms of the optimal power allocation and the partner selection region. The study is based on a network geometry of a fixed source node and a destination node with a range of potential partner node locations. Numerical results of optimal power allocation and the partner selection region are generated, and contour graphs of the resulting cooperative energy savings achieved from cooperations are provided using MATLAB. Results have indicated that cooperations can seek for potential partner nodes within a specified region to form energy efficient communications in WSNs operating in indoor environments. Furthermore, we have compared our results to the existing work which studies cooperations over flat fading channels, and several interesting findings have been revealed.