The Research On Virtual MIMO-Based Low-Power Wireless Sensor Network

In recent years, with the development of electronics technology and wireless communication technology, there was an emergence of low-cost, low-power, and multifunctional sensor nodes. These sensor nodes are small, and they can make short-distance communication. These tiny sensor nodes consist of sensors, data processing components and communications components, and the sensor nodes achieve the concept of wireless sensor network. Wireless sensor network expand the communication between human and nature, and it is a landmark of traditional sensors.At present, because of the potential applicative value, the research on wireless sensor network (WSN) has been getting many extensive attentions. Different from other wireless communication systems, wireless sensor networks can not be added generally because of the battery-powered sensor nodes. Therefore, how to improve the energy efficiency of sensor nodes and prolong the network lifetime of sensor network is the key issues for its research.The extents of wireless sensor networks interact with the environment are larger than ordinary network, so the network operations are affected by environmental impacts in a large extent. Communication between network nodes due to direct, diffraction and scattering of transmission arising from the multi-path fading phenomenon, therefore, only according to the traditional means of simply nodes communication can not minimize the network energy consumption.MIMO (Multiple-input, Multiple-output) technology is an important technology in wireless communications'field. It can use random decline effectively which may exist in the multipath propagation and improve communication system capacity and spectral efficiency. Research shows that at the same transmit power and bit error rate performance requirements, the MIMO system relative to the Single-input, Single-output (SISO) system can support higher transfer rates. In other words, under the request of the same system throughput, MIMO systems can save more transmission energy than the SISO system. However, due to the size restrictions on sensor nodes, the antenna array of MEMO system can not be accommodated in a single node. Therefore, the program of virtual MIMO was proposed. In the program, multiple nodes are in a coalition and to form multi-antenna systems. As a result, how to adopt virtual MIMO to design the optimal energy-efficient wireless sensor networks becomes a research hotspot.In this paper, we first introduced the simple transmit diversity technology in wireless communications,-Alamouti space-time coding. Then based on the description of the MIMO system model and principle, describes the MIMO system in wireless sensor network. At last, we also describe the classical routing protocols and topology control of wireless sensor network.Based on the Alamouti space-time coding and virtual MIMO technology, we improve the wireless sensor networks'routing protocol LEACH, and propose a new grid clustering algorithm. The new algorithm can effectively improve the wireless sensor network's life by simulation evidence.Broadcasting is one of the most basic means of communication in wireless sensor networks, and its purpose is to send information from the source node sends to the rest node of network. In this paper, describe the minimum energy broadcasting problem which based virtual MIMO cooperative multihop broadcasting schedule, and improve the GFA algorithm. Compare with the GFA algorithm, the improved algorithm can save the transmitting energy, reduce the nodes'energy consumption and prolong the life of wireless sensor network.