دانلود رایگان مقاله تشخیص پوشش حفره مبتنی بر درخت و روش درمان در شبکه های حسگر بی سیم

Abstract

In wireless sensor networks, coverage is a fundamental issue affecting the quality of service. A coverage hole may appear anywhere in the area being monitored at any time because of many reasons. Thus, hole detection and healing have become major challenges towards achieving perfect coverage. This study provides a novel algorithm using trees and graph theory to detect and describe the existing holes in the region of interest. Simulation results show that the tree-based method can indicate the location, size, and shape of coverage holes accurately. Based on the results for hole detection, a tree-based healing method is also proposed. The method is divided into two phases, namely, hole dissection and optimal patch position determination. Results obtained from the experimental evaluation reveal that the proposed healing method can increase the coverage rate with only a few additional sensors compared to other related methods.

7. Conclusions

In this study, the problem of coverage hole detection and healing is considered. We introduce the concept of trees to detect, locate, and describe coverage holes. Based on the tree, we can determine the location and shape of the corresponding coverage hole and estimate its size. The tree-based method provides the global view of holes clearly and estimates the size of holes more accurately compared with the conventional boundary node detection method. We also proposed a coverage hole healing method based on the results of hole detection. The healing method is divided into two phases, namely, hole dissection and optimal patch position determination. These two phases ensure that the overlap between the sensing ranges of the additional sensors becomes as little as possible. Compared with the Delaunay triangulation-based and the Voronoi based methods, the proposed healing method can increase the coverage rate efficiently with the same number of additional sensors. Therefore, the proposed scheme serves as a useful tool for detecting and healing coverage holes. Future studies should address the coverage problem in directional sensor networks, such as camera networks.