Energy Efficient Relay Selection Algorithm for Virtual MIMO Cooperative Networks

In this paper, we propose a distance based energy efficient multiple relay selection algorithm for cooperative virtual Multiple-Input-Multiple-Output (MIMO). The fundamentals of this method is to forward the source signal using the node which minimizes the end-to-end total path distance, such that the total energy cost per bit is reduced at the relay and at the source. An energy efficient multiple relay selection algorithm is proposed to minimize the energy cost per bit while achieving a target system performance in terms of BER at the destination. The core of the proposed relay selection method is selecting the node set that minimize the overall path lengths. We present the impact of the relay location and the constellation size for different MIMO configuration, and prove numerically that minimizing the sum of all path link length leads to lower energy consumption under the same performance requirement for MIMO, Multiple-Input-Single-Output (MISO) and Single-Input-Multiple-Output (SIMO) configuration. We compare the performance of MIMO, SIMO and MISO in terms of energy consumption and we present the results in terms of energy cost per bit against transmission distance. The results presented show that the proposed algorithm outperforms non optimized MIMO and traditional virtual MIMO communication in terms of energy consumption per bit for fixed rate and variable rate systems.