Energy efficient virtual MIMO-based cooperative communications for wireless sensor networks

An energy-efficient virtual multiple-input multiple-output (MIMO)-based communications architecture is proposed for energy-limited, distributed and cooperative wireless sensor networks. Assuming a space-time block coding (STBC) based MIMO system, the energy and delay efficiencies of the proposed MIMO-based communications scheme are derived using analytic techniques. The efficiency of the proposed MIMO-based communication system is related to the system and channel propagation parameters. These investigations show that MIMO techniques can be made to provide significant energy savings and delay efficiencies at the same time with judicious choice of system parameters at the design level. Further, the dependence of energy efficiency of proposed MIMO-based wireless sensor network on fading coherence time and the required amount of training is analyzed. These results justify the application of proposed cooperative MIMO-based scheme in wireless sensor networks even after allowing for additional training overheads.