Research Of The Coverage And Connectivity Algorithms In Wireless Sensor Networks

Recent technological advances in micro-electro-mechanical systems (MEMS) technology, wireless communications, and digital electronics have led to the emergence of large-scale sensor networks. It has been predicted to have a wide range of applications related to national security, military, environment, health care, home and other commercial areas. Many researchers are currently engaged in developing the technologies needed for different layers of the sensor networks.Two of the most fundamental problems in WSN are connectivity and coverage. Coverage means that overall area should be sensed by all nodes so that the observer can obtain the whole information. In the paper, we computer the coverage degree in the wireless sensor network, and propose the CTS (Coverage Template Scan) algorithm by introducing the concept of Coverage Template. The CTS algorithm takes full attention to both the different sensing range of nodes and the boundary effect of the coverage range, so it not only solves the k coverage problem, but also strengthens the adaptation of the actual application.One effective approach to conserving system energy in wireless sensor networks is to keep only a minimal number of sensors active. The problem of computing such minimal active sensor set, which covers the target region completely, is NP-hard. This paper presents an optimized algorithm to seek the minimal cover set based on genetic algorithm. Experimental results show that the algorithm can make an excellent and reasonable balance between coverage effect and active node number, and which obtains the minimal cover set is more adaptable for practical application need.Connectivity indicates every node can communicate with any other nodes in WSN. It is the precondition to create a self-organization network. The paper presents the necessity and sufficient condition though investigate the relationship between coverage and connectivity. The communication graph induced by the cover set computed by Genetic algorithm is connected if sensor's communication radius is at least twice of its sensing radius. In case of sensor's communication radius is smaller than twice of its sensing radius, a minimum spanning tree (MST) based connection algorithm is proposed to ensure the communication connectivity of the cover set.The paper gets the Minimal Connected Cover Set though the above research of connectivity and coverage problem.