Combined Ieee 802.15.4 Physical Layer and Virtual Multiple Input Multiple Output (v- Mimo) Transmissions for Energy Efficient Wireless Sensor Networks

A Wireless Sensor Network (WSN) consists of a hundred of sensor nodes 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 maximizes the lifetime of sensor’s batteries. One of the available solutions for improving the energy efficiency of smart WSNs is by using the 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 exploited the advantages Provided by the virtual MIMO technique (i.e. by 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, decoding and forwarding 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 in any other cluster. In this work, we studied the effects of Rayleigh flat fading channels which increase the retransmission error of data packets. Our simulation results show that the use of the advantages of virtual MIMO and one central/rechargeable relay node achieves only low energy efficiency for the Signal to Noise Ratio (SNR) range between –20 to 20dB over the Rayleigh flat fading channel. However, the second scenario achieves high energy efficiency due to the clustering technique and the central relay nodes with direct transmission in each cluster.