Dynamic selection on the number of antennas for cooperative MISO in WSNs

Energy efficiency in wireless sensor networks (WSNs) is a crucial factor affecting the performance of the networks since long-time un-interrupted energy supply in WSNs is almost impossible in most cases. Recent research results have demonstrated that under some particular conditions, cooperative multi-input-multi-output (MIMO) systems can save large amount of energy in comparison with the traditional single-input-single-output (SISO) scheme. In this paper, the effect of the number of antennas on the energy consumption in cooperative multi-input-single-output (MISO) scheme was analyzed. We found a dynamic selection on the number of antennas (DSNA) model to obtain an optimized number of cooperative antennas at the transmit side dynamically according to the transmission distance, to minimize the total energy consumption. The performance of the proposed DSNA model was investigated for the WSNs with different network scales. Experimental results showed that the cooperative MISO scheme with the proposed DSNA model was more energy-efficient than the traditional cooperative MISO and SISO schemes.