Research On Wireless Sensor Network Coverage Optimization By Fish-swarm Algorithm

One of the most fundamental problems in wireless sensor networks is the coverage control problem,which reflects how well a region is apperceived.When a wireless sensor network (WSN) is deployed in the unknown or hostile environment, randomly deployment, such as air-dropped from an aircraft,can be the only way.In such a situation, the sensing coverage performance of the WSN is a random variable.So it needs some control strategies to ensure the area of interest monitored effectively by the sensing nodes.The WSN coverage control can be transformed into a kind of constrained optimization problems, the optimization goal is to minimize energy consumption and to extend the life of the network on the condition that it guarantees the quality of sensing coverage. Artificial fish swarm algorithm (AFSA) is a new kind of intelligent optimization algorithm, which is insensitive to initial value and has the strength of fast global covergence and high real-time. This paper researches the optimization mechanism of AFSA for some improvements to make the improved AFSA be applied in WSN coverage.The main work of this paper includes:1.Due to the high density of distributing nodes in wireless sensor networks, aiming at maximizing the network coverage and minimizing the number of working nodes as a network optimization goal, an optimal model for coverage in wireless sensor network is established and a coverage optimization strategy based on fish swarm algorithm is proposed.Simulation results show that the proposed strategy can get an optimal selection of the set of nodes rapidly,improve the energy consumption and the real time capability of nodes scheduling.2.Generally, the self-government of WSN is achieved by the clustering structure. The strategies which make the most redundant nodes asleep don't get the least energy consumption and it can't assure every node consumes its energy evenly. Considering the cluster energy and the coverage quality, the paper proposes a node scheduling strategy based on fish-swarm algorithm. Simulation results demonstrate that the proposed strategy can save more energy and make the life of network longer while offering the required coverage.3.In a hybrid sensor network that contains a small amount of mobile nodes,traditional virtual force algorithm(VFA) can not remove the impact of stationary nodes because force exerted by stationary nodes will fetter the movements of mobile nodes,which will strongly deteriorate the performance of coverage. Further more,the energy heterogeneity of mobile nodes is not considered in VFA.This paper proposes a parallel fish-swarms strategy to maximize the network coverage rate and to balance the energy consumption of the mobile nodes.Simulation results demonstrate that the proposed strategy can get better coverage rates than VFA,and performs better in energy balance of mobile nodes.