Energy efficiency of virtual MIMO transmission schemes for cluster-based wireless sensor networks

In this paper, a cluster-based virtual multiple-input multiple-output (MIMO) transmission architecture is proposed for energy-constrained wireless sensor networks. In the proposed architecture, instead of using cluster members as cooperative nodes, multiple cluster heads cooperate to form virtual antenna array so that MIMO transmission can be implemented. According to the MIMO techniques used in this architecture, two different schemes, vertical Bell Laboratories layered space-time (V-BLAST) based cluster heads cooperative transmission (VCHCT) and space time block code (STBC) based cluster heads cooperative transmission (SCHCT), are developed. Based on the communication energy consumption model, the overall energy consumption model for both VCHCT and SCHCT are derived. Detailed comparison between these two schemes and the original low-energy adaptive clustering hierarchy (LEACH) is performed to investigate the performance of these two schemes. Simulation results not only verify the theoretical analysis but also show that the two schemes have their specific application scenarios. When the sink is far from the sensor area, SCHCT scheme is much more energy efficient than LEACH and VCHCT scheme even if it consumes additional inter-cluster communication energy. When the distance to sink is near the sensor area, VCHCT is preferable.