A virtual MIMO transmission scenarios for high energy efficiency smart wireless sensor networks over Rayleigh flat fading channel

A Wireless Sensor Network (WSN) consists of a hundred of sensor nodes which deployed in sensing fields in order to serve various applications. The limited resources of sensor nodes such as energy source, computational ability and communication bandwidth are the most important challenges in designing a reliable smart WSN which guarantees the connectivity and maximizing the lifetime of sensors batteries. One of the available solutions of improving the energy efficiency of smart WSNs is using Virtual Multiple Input Multiple Output (V-MIMO) technology adapted to sensor nodes. In this paper, we proposed a high energy efficiency smart WSN in which we exploit the advantages given by virtual MIMO technique (i.e. reducing the multipath fading channel). Our network transmission has two scenarios. The first scenario is based on deploying one rechargeable relay node at the center of the sensing field which is responsible for receiving data packets from the source node, decode and forward them to a destination node, while the second scenario is based on dividing the sensing field into clusters where each cluster has a rechargeable relay node which transfers data packets to a destination node in the same cluster or any other cluster. In our paper, we studied the effects of Rayleigh flat fading channels which cause increasing the re-transmission error of data packets. Our simulation results show that using the advantages of virtual MIMO and one central/rechargeable relay node achieve low energy efficiency for Signal to Noise Ratio (SNR) range between -20 to 20dB over Rayleigh flat fading channel. However, the second scenario achieves high energy efficiency due to clustering technique and the central relay nodes with direct transmission in each cluster.