The Study Of Target Coverage In Wireless Multimedia Sensor Networks

The widely use of Internet of Things promotes the development of sensing technology and the research and development of wireless sensor networks. With the development of the people’s demand, wireless multimedia sensor network (WMSN) comes into being, in which the coverage control is the basic problem,it presents the WMSN’s perception on the physical world, and has a direct impact on the QOS of entire network.In WMSN, the perception of multimedia sensor node is directional. It is different from the omni-directional perception model. The sensing area of directional model is fan-shaped. The perceptual perspective and directional are important features of directional sensor nodes.At the same time, WMSN includes multimedia information, whose data amount is large and complex, the transmission consuming much more source. Therefore, using the source reasonably is very important to WMSN. In this paper, basing on directional sensing model, studying the target coverage algorithm and homeostasis-inspired autonomous communication.The Greedy Algorithm(GA) and the Enhanced Greedy Algorithm(EGA) are relatively simple and low computational complexity to adjust sensor nodes work directions, but their results are local optimality and don’t take the target’s coverage into consider. In this paper, based on the EGA, the Directions Optimization Algorithm Based on Priority (DOBP) is proposed, considering the target coverage simultaneously, trying to cover the key nodes of the networks. For the selection of work direction of sensor nodes, DOBP takes the target’s coverage into consideration, for the target with small coverage, will be got a relatively higher priority, by contrast, the target with high coverage, will be got a relatively low priority. Sensor nodes select the working directions according to the total coverage of the target priority level in their different direction. For the communication of wide-band event signal in WMSN, simulating the homeostasis automatic property, establishing Homeostasis-inspired Autonomous Communication (HAC), so that the sensor node can cooperate automatically, carry on the event signal communication effectively. This algorithm can get a sufficient number of data samples from the event signal with the lowest energy expenditure, realize the exact reconstruction for event signal, and does not need any feedback messages from the nodes, greatly reducing the amount of information in communication.For experiment, comparing and analyzing the coverage performance of EGA and DOBP. Simulation results show that factors’effects on the coverage and the lifetime of network, including the number of sensors, the number of targets, sensing radius. At the same time, analysis the performance of EGA combined with HAC and DOBP combined with HAC on the influence of the lifetime of network. Performance evaluation reveal that DOBP and HAC can successfully strengthen the coverage of key node and prolong the lifetime of network.