Research On Invulnerability Optimization Strategy Through Topology Reconstruction For Wireless Sensor Networks

Wireless Sensor Network(WSN)is formed by a large number of sensor nodes which are low cost and have signal acquisition,wireless communication and other functions through self-organized way.And it completes the task of collection and transmission the data of monitoring area through mutual cooperation of sensor nodes.WSN is widely applied in military surveillance,environmental monitoring,urban traffic management and so on,recently.Due to the network is often deployed in the harsh environment and sensor nodes are subject to their own energy and broadband communication restrictions,the network is vulnerable to be damaged and can not work effectively.So,the study of the problem of the network invulnerability optimization has become a very important topic.Through the reasonable analysis to the topological structure of the network,this paper optimizes the network invulnerability from the point of view of the topology reconstruction which includes two aspects of failure prevention and topological repair,and puts forward two algorithms accordingly.(1)The paper proposes a topology optimization algorithm to prevent the failure of scale-free network which operates normally and improve the network invulnerability.The algorithm firstly analyzes the robust and fragile topological features of the network and then removes some links among the network to balance the node load and reduce the probability of the overload of node as much as possible.In order to further improve the network invulnerability to against the external attacks,the algorithm selects the node with relatively high invulnerability in each adjacent network and constructs a connected ring interchange topology among them that according to the thought of the traveling salesman problem(TSP).The simulation results show that this kind of topology reconstruction algorithm can effectively improve the network transmission capacity and the invulnerability of the network.(2)Based on a partitioned WSN,the paper presents an invulnerability optimization algorithm to repair the network connectivity which opts to employ the fewest relay nodes.The algorithm forms the largest inner simple cycle at the first phase which referred to as backbone polygon.Then,the initial 1-connected topology is established where the terminals of the backbone polygon act as a core mesh and each partition that is not part of the backbone polygon is connected to the backbone polygon over the shortest path.In order to avoid the network divided again that due to the failure of a single relay node,the second phase of the algorithm is to form a bi-connected inter-partition topology among the backbone polygon and partitions that can boost the application robustness,improve the fault tolerance and balance the inter-segment traffic in a network.