Energy Efficiency for Cooperative MIMO Wireless Sensor Networks with Optimal Constellation Size under MPSK Modulation Scheme

We consider the energy efficiency for wireless sensor networks (WSNs) where all the nodes operate on batteries so that the total energy consumption should be minimized. One feasible and effective approach is to treat several individual single-antenna nodes which cooperative at the transmitter and receiver as multiple-antenna, i.e., cooperative MIMO. In this context, for the given bit error rate, we first analyze the total energy consumption under the MPSK modulation scheme by using space time block coding in the cooperative MIMO WSNs. Meanwhile, the upper bound of total energy consumption will be deduced. For both short and long transmission distance, we show the trend of the total energy consumption over the constellation size and obtain the optimal constellation size especially achieving the lowest system energy consumption. Additionally, the total energy consumption can be significantly saved by utilizing cooperative MIMO especially at long transmission distance.