Area detection and measuring is one of the most important problems in Wireless Sensor Network (WSN) because it mainly relates to the continuity and functionality of most routing protocols applied to the Region of Interest (ROI). Electronics failure, random deployment of nodes, software errors or some phenomena such as fire spreading or water flood could lead to wide death of sensor nodes. The damage on ROI can be controlled by detecting and calculating the area of the holes, resulting from the damaged sensor networks. In this paper, a new mathematical algorithm, Wireless sensor Hole Detection algorithm (WHD), is developed to detect and calculate the holes area in ROI where the sensor nodes are spread randomly. WHD is developed for achieving Quality of Service (QoS) in terms of power consumption and average hole detection time. The dynamic behavior of the proposed WHD depends on executing the following steps. Firstly, WHD algorithm cuts down the ROI into many cells using the advantage of the grid construction to physically partition the ROI into many small individual cells. Secondly, WHD algorithm works on each cell individually by allocating the nearest three sensor nodes to each of the cell’s coordinates by comparing their positions, WHD connects each cell’s coordinate points with the selected sensor nodes by lines which construct a group of triangles, then WHD calculates the area of upcoming triangles. Repeating the previous step on all the cells, WHD can calculate and locate each hole in the ROI. The performance evaluation depends on the NS-2 Simulator as a simulation technique to study and analyze the performance of WHD algorithm. Results show that WHD outperforms, in terms of average energy consumption and average hole discovery time, Path Density algorithm (PD), novel Coverage Hole Discovery Algorithm (VCHDA) and Distriputed Coverage Hole Detection (DCHD).

Introduction

Wireless Sensor Network (WSN) is one of the new technologies for detecting and monitoring life phenomenon. WSNs are composed of massive number of sensor nodes operated by small batteries, sensor nodes are mostly deployed in open and unprotected environments. Sensor nodes have significant limitation in communication capabilities and battery power. Nowadays sensor nodes are spread in large scale due to rapid technological advances in micro-electronic industries and the new developed routing protocols which save more communication and computation power (Chen et al., 2017). WSN’s can be used in various applications such as target tracking, environmental monitoring, and battlefield surveillance. WSN are composed of hundreds or thousands sensor nodes operated by small batteries, they are spread in open environments to detect and collect information from the surrounded phenomenon (Debnath et al., 2016). Then remote base station receive report messages from the sensor nodes (Zhao et al., Jan 2017). Various applications are dependent on WSNs such as military field exploration, flood of water, border protection and forest fires (Wua et al., 2016; Ahadipour and Haddad, January 2017; Mahapatra et al., 2017). WSNs have unique characteristics due to their physical design, such as unreliability of sensor nodes, undefined network topology, high computation and communication power consumption and lots of storage difficulties (Jan et al., 2017; Kadu and Jaini, 2015), So many challenges are presented in the solutions design and applications development of WSNs. In the real life applications, sensor nodes are randomly scattered over the ROI which allow some uncovered areas (Holes) to be present in the ROI, which significantly degrade the network performance. The hole can be defined as the amount of area within the ROI that is not covered by any living sensor. The holes also can be created by the dynamic operations of the sensor nodes. Sensor nodes usually vanished by impact of random deployment, over heat, movement of animals, vehicles and people accidents. Such failures occur due to the static nature and the random deployment of the sensor nodes (Kumar and Dhingra, 2015; Beghdad and Lamraoui, 2016). The failure within any part of the network directly affects the performance of the total network locally and globally. The presence of holes in ROI definitely affect the routing paths, may cause failure of the routing protocols or separation of the network to many individual small networks.