Coverage Control For Directional Sensor Networks

With the development of wireless communication technology, micro-electromechanical systems technology, embedded technology, Wireless Sensor Networks( WSNs) have attracted more and more attention and become a hot issue. WSNs have the advantages of distribution, low-cost and flexibility, and so on. They had been widely applied in environmental protection, health care, intelligent building, battlefield surveillance.Firstly, the problem of an effective way to achieve the goal of full coverage control with strong connectivity for two-dimensional traditional WSNs and three-dimensional traditional WSNs is proposed in this paper. To achieve full coverage with the least sensors, the most efficient 1-coverage topologys in two-dimensional WSNs and three-dimensional WSNs are used. In order to make every sensor reach a proper point without collisions and moving out of the target field to cover the area fully, virtual potential functions are proposed to design the appropriate controller, Compared with the existing coverage strategy, the proposed strategy needs far more less sensors and achieves full coverage while preserving global connectivity much more effectively. It is shown that the proposed algorithm is proved to be convergent through the Lyapunov stability theory, and some simulations are used to verify the effictiveness of the proposed algorithm.Secondly, because the traditional multi-directional sensor networks is not accurate enough for the study of multi-media sensors,the problem of maximum directional area coverage in Directional Sensor Networks( DSNs) is studied, which is more fit for multi-media sensor networks. A developed approach,namely improved rotation angle distributed greedy algorithm based the improved strategy of chosen direction searching is proposed. In this approach,the priority setting stratgy is recomposed according to the initial redundant coverage rate, the rotation angle of sensor while looking for optimal direction is supposed to decrease with the increase of coverage rate. Compared with previous Dgreedy algorithm,the improved Dgreedy algorithm gets higher accuracy and coverage rate without extension of time. Finally,some simulations are used to illustrate the effictiveness of the proposed algorithm.At last, because full coverage is offen required in real application for DSNs except for coverage development,the problem of full coverage in directional sensor networks is studied furtherly, a novel coverage strategy with stream-based obstacle avoidance is presented to coordinate the mobile sensors to achieve full coverage. In this strategy, the number of sensors needed is calculated based on the 1-coverage network topology, a potential-based sensor placement algorithm is developed, where a stream function is applied to avoid collisions. It is shown that the proposed potential-based sensor placement algorithm is convergent. Finally, some simulations are used to demonstrate the effectiveness of the proposed algorithm.