Energy Efficient Cooperative MIMO Communication for Uncorrelated Data Transmission at Wireless Sensor Network

Abstract

Energy efficient data transfer is one of the key factors for wireless sensor network (WSN). Cooperative MIMO explores the wireless communication schemes between multiple sensors emphasizing the multiple input multiple output (MIMO) structure. In this paper, an energy efficient cooperative technique is proposed for a WSN where selected numbers of sensors at the transmitting end are used to form a MIMO structure wirelessly connected with selected number of sensors at the receiving end. The selection of nodes in the transmitting end is based on a selection function which is a combination of channel condition, residual energy, inter sensor distance in a cluster and geographical location whereas the selection in receiving side is performed on the basis of channel condition. Energy and delay models are evaluated for uncorrelated data scenario and life time analysis is done. Experimental results show that the selected MIMO structure outperforms the unselected MIMO. Index Terms—Cooperative technique, uncorrelated data, selec- tive approach, MIMO, wireless sensor networks. I. INTRODUCTION With recent hardware advancements allow more signal processing functionality to be integrated into a single sensor chip. RF transceiver, A/D and D/A converters, base band processors, and other application interfaces are integrated into a single device to be used as a smart wireless node. A wireless sensor network typically consists of a large number of sensor nodes distributed over a certain region. Monitoring node (MN) monitors its surrounding area, gathers application- specific information, and transmits the collected data to a data gathering node (DGN) or a gateway. Energy issues are more critical in the case of MNs rather than in the case of DGNs since MNs are remotely deployed and it is not easy to frequently change the energy sources. Therefore, the MNs have been the principal design issue for energy limited wireless sensor network design. MIMO (2), (3) is a potential candidate for energy efficient design for a targeted probability of bit error rate at the receiver. There has been a great amount of research on various MIMO techniques (including MISO and SIMO) in wireless communication systems due to its diversity and BER improvements. But the fact that MIMO techniques could require complex transceiver circuitry and signal processing leading to large power consumptions at the circuit level has precluded the application of MIMO techniques