Research On Coverage Problem Of ZigBee Protocol Based Mobile Sensor Network

With the development of sensor technique, Micro-Electro-Mechanical Systems, network, wireless communications and other modern technology, wireless sensor networks are becoming an active research area. Wireless sensor network is composed of massive collaborative sensor nodes, and each node has the abilities of sensing, computing and communicating. It has synthesized sensor techniques, embedded computations, distributed information processing and wireless communication technique, which can cooperate to complete real-time monitoring, sensing and gathering of object information, and then transmit it to the user after information processing. At present, wireless sensor network has a very broad application in military defense, industrial control, urban management, biomedicine, environmental monitoring, disaster and dangerous regional remote control, etc.As network coverage is the prime issue of wireless sensor network, this paper mainly discusses the coverage optimization control of wireless sensor network.The paper proposes a novel way of hardware design for mobile sensor node, which is based on mobile robot vehicle with high-performance DSP processor, power supply module, driving module, ZigBee wireless communication module and low-cost, low-power sensors. And then experimental implementations, which contain network configuration test and motor control test, are introduced based on the designed nodes. The results are also presented to demonstrate the effectiveness of the proposed approach, which satisfies the requirements of mobile sensor network, that is, mobilization, data collection, data processing and data transportation.Founded on the coverage optimization control problem of wireless sensor network, the paper also proposes a Hexagonal Grid-based Sensor Deployment Algorithm (HGSDA). The proposed algorithm, under the condition of initial random placement of sensor nodes, first divides the target region into small hexagonal grids, and then applies ant colony algorithm into searching the redundant nodes in the hexagonal grids in order to deploy them in the proper centers of hexagonal grids which have no sensor nodes in their own areas. Thus, it not only achieves one hundred percent coverage degree, but also cut the distances of moving nodes. Simulation results and tests based on the designed nodes show that the HGSDA could not only cover the area effectively and completely, but also reduce the moving distances of mobile nodes. Besides, the algorithm has good adaptability.