Efficient Algorithms for Distributed Detection of Holes and Boundaries in Wireless Networks

We propose two novel algorithms for distributed and location-free boundary recognition in wireless sensor networks. Both approaches enable a node to decide autonomously whether it is a boundary node, based solely on connectivity information of a small neighborhood. This makes our algorithms highly applicable for dynamic networks where nodes can move or become inoperative. We compare our algorithms qualitatively and quantitatively with several previous approaches. In extensive simulations, we consider various models and scenarios. Although our algorithms use less information than most other approaches, they produce significantly better results. They are very robust against variations in node degree and do not rely on simplified assumptions of the communication model. Moreover, they are much easier to implement on real sensor nodes than most existing approaches.Comment: extended version of accepted submission to SEA 201

New Holes and Boundary Detection Algorithm for Heterogeneous Wireless Sensor Networks

Hole is an area in wireless sensor network (WSN) around which nodes cease to sense or communicatedue to drainage of battery or any fault, either temporary or permanent. Holes impair sensing andcommunication functions of network; thus their identication is a major concern. In this paper, adistributed solution is proposed for detecting boundaries and holes in the WSN using only the nodesconnectivity information and estimated distance between nodes. The run of our protocol is dividedinto four main phases. In the rst phase, each node discovers its coverage neighbors and collects theirinformation. In the second phase, each node communicates with its neighbors to nd whether its sensingrange is fully covered by the sensing ranges of its neighbors. In the third phase, the boundary nodesconnect with each other to complete the boundary information. In the fourth phase, a boundary subgraphamongst boundary nodes is constructed and classied either as an interior or an exterior boundary.Simulation results show that our approach improves the energy and reduces the number of boundarynodes over existing algorithms

Distributed Recognition of Reference Nodes for Wireless Sensor Network Localization

All known localization techniques for wireless sensor and ad-hoc networks require certain set of reference nodes being used for position estimation. The anchor-free techniques in contrast to anchor-based do not require reference nodes called anchors to be placed in the network area before localization operation itself, but they can establish own reference coordinate system to be used for the relative position estimation. We observed that contemporary anchor-free localization algorithms achieve a low localization error, but dissipate significant energy reserves during the recognition of reference nodes used for the position estimation. Therefore, we have proposed the optimized anchor-free localization algorithm referred to as BRL (Boundary Recognition aided Localization), which achieves a low localization error and mainly reduces the communication cost of the reference nodes recognition phase. The proposed BRL algorithm was investigated throughout the extensive simulations on the database of networks with the different number of nodes and densities and was compared in terms of communication cost and localization error with the known related algorithms such as AFL and CRP. Through the extensive simulations we have observed network conditions where novel BRL algorithm excels in comparison with the state of art

Resilient networking in wireless sensor networks

This report deals with security in wireless sensor networks (WSNs), especially in network layer. Multiple secure routing protocols have been proposed in the literature. However, they often use the cryptography to secure routing functionalities. The cryptography alone is not enough to defend against multiple attacks due to the node compromise. Therefore, we need more algorithmic solutions. In this report, we focus on the behavior of routing protocols to determine which properties make them more resilient to attacks. Our aim is to find some answers to the following questions. Are there any existing protocols, not designed initially for security, but which already contain some inherently resilient properties against attacks under which some portion of the network nodes is compromised? If yes, which specific behaviors are making these protocols more resilient? We propose in this report an overview of security strategies for WSNs in general, including existing attacks and defensive measures. In this report we focus at the network layer in particular, and an analysis of the behavior of four particular routing protocols is provided to determine their inherent resiliency to insider attacks. The protocols considered are: Dynamic Source Routing (DSR), Gradient-Based Routing (GBR), Greedy Forwarding (GF) and Random Walk Routing (RWR)

Reliable Communication using Path Recovering in Wireless Sensor Network

Sensor technology is one in every of the quick growing technologies within the current scenario. And it's big selection of application additionally. The power of sensors to figure while not being monitored by someone is its distinctive quality. Wireless device network comprise of little sensors that have minimum communicatory and procedure power. Several anomalies square measure gift in WSNs. One such drawback may be a hole. Space barren of any node will be brought up as a hole. This degrades the performance of the full network. It affects the routing capability of the network terribly badly. The formation of holes in an exceedingly WSN is unavoidable thanks to the inner nature of the network. This paper deals with detective work and healing such holes in associate on demand basis

Boundary node selection algorithms in WSNs

Physical damage and/or node power exhaustion may lead to coverage holes in WSNs. Coverage holes can be directly detected by certain proximate nodes known as boundary nodes (B-nodes). Due to the sensor nodes' redundant deployment and autonomous fault detection, holes are surrounded by a margin of B-nodes (MB-nodes). If all B-nodes in the margin take part in the hole recovery processes, either by increasing their transmission power or by relocating towards region of interest (ROI), the probability of collision, interference, disconnection, and isolation may increase affecting the rest of the network's performance and QoS. Thus, distributed boundary node selection algorithms (BNS-Algorithms) are proposed to address these issues. BNS-algorithms allow B-nodes to self-select based on available 1-hop information extracted from nodes' simple geometrical and statistical features. Our results show that the performance of the proposed distributed BNS-algorithms approaches that of their centralized counterparts. © 2011 IEEE

Coverage Assessment and Target Tracking in 3D Domains

Recent advances in integrated electronic devices motivated the use of Wireless Sensor Networks (WSNs) in many applications including domain surveillance and mobile target tracking, where a number of sensors are scattered within a sensitive region to detect the presence of intruders and forward related events to some analysis center(s). Obviously, sensor deployment should guarantee an optimal event detection rate and should reduce coverage holes. Most of the coverage control approaches proposed in the literature deal with two-dimensional zones and do not develop strategies to handle coverage in three-dimensional domains, which is becoming a requirement for many applications including water monitoring, indoor surveillance, and projectile tracking. This paper proposes efficient techniques to detect coverage holes in a 3D domain using a finite set of sensors, repair the holes, and track hostile targets. To this end, we use the concepts of Voronoi tessellation, Vietoris complex, and retract by deformation. We show in particular that, through a set of iterative transformations of the Vietoris complex corresponding to the deployed sensors, the number of coverage holes can be computed with a low complexity. Mobility strategies are also proposed to repair holes by moving appropriately sensors towards the uncovered zones. The tracking objective is to set a non-uniform WSN coverage within the monitored domain to allow detecting the target(s) by the set of sensors. We show, in particular, how the proposed algorithms adapt to cope with obstacles. Simulation experiments are carried out to analyze the efficiency of the proposed models. To our knowledge, repairing and tracking is addressed for the first time in 3D spaces with different sensor coverage schemes

Neighbor Adjacency based Hole Detection Protocol for Wireless Sensor Networks

AbstractCoverage and communication holes may appear in sensor networks due to limited battery life, presence of obstacles and physical destruction of nodes. These holes have a negative impact on the network performance. In order to ensure that optimum area in sensing field is covered by sensors, coverage holes must be detected. This paper proposes an adaptive routing algorithm based on neighbor adjacency for detecting coverage holes in sensor networks. Proposed algorithm can compute location of holes in the network from remote locations based on hop count measure computed from network statistics. Simulation results show that algorithm gives better performance in terms of end to end delay and packet delivery fraction as compared to previous works. Simplicity and efficiency are the key features that distinguish this work from existing routing and hole detection schemes