Abstract
Connectivity has significance in both of data collection and aggregation for Wireless Sensor Networks (WSNs). Once the connectivity is lost, relay nodes are deployed to build a Steiner Minimal Tree (SMT) such that the inter-component connection is reestablished. In recent years, there has been a growing interest in connectivity restoration problems. In previous works, the deployment area of a WSN is assumed to be flat without obstacles. However, such an assumption is not realistic. In addition, most of the existing strategies chose the representative of each component, which serves as the starting point of relay node deployment during the connectivity restoration, either in a random way or in the shortest-distance based manner. In fact, both ways of representative selection could potentially increase the length of the SMT such that more relay nodes are required. In this paper, a novel connectivity restoration strategy is proposed—Obstacle–Avoid connectivity restoration strategy based on Straight Skeletons (OASS), which employs both the polygon based representative selection with the presence of obstacles and the straight skeleton based SMT establishment. The OASS is proved to be a 3- approximation algorithm with the complexity of , and the approximation ratio can reduce to while it satisfies a certain condition. The theoretical analysis and simulations show that the performance of the OASS is better than other strategies in terms of the relay count and the quality of the established topology (i.e., distances between components, delivery latency and balanced traffic load) as well.
Highlights
Wireless sensor networks (WSNs) are well-known by their significant advantages in monitoring, such as battlefield surveillance, environment monitoring and biological detection
This paper is dedicated to the connectivity restoration problem, which is formally stated as follows: Given a graph G with n disjoint components Ci s that consist of sensors with a transmission range r and obstacles Os, the goal is to provide an efficient solution that ensures that n components will be
Relay Nodes (RNs) being deployed along a planned route at an interval r to restore the connectivity, we can infer each unique relay node consumption function with respect to the number of representatives n and the length Lt of a tree t constructed by OASS, Atc and A Minimum Spanning Tree (MST), respectively
Summary
Wireless sensor networks (WSNs) are well-known by their significant advantages in monitoring, such as battlefield surveillance, environment monitoring and biological detection. All data collected are forwarded toward a base station along at least a multi-hop wireless path In this case, the reachability between any pair of sensors implies the importance of the network connectivity. Most strategies of this type choose the representative either in a random way or in the shortest-distance based manner Both ways of representative selection could potentially increase the length of the SMT such that more RNs are required. This paper presents an Obstacle–Avoid connectivity restoration strategy based on Straight. We devise a straight skeleton based algorithm, SSIN, to build an SMT such that the shortest inter-component connection is achieved. Each straight skeleton will be placed within the potential convex hull of MST as the deployment route for RNs. if multiple line-segments between pairs of nodes have obstacles, the SSIN is an option to avoid obstacles.
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