Distributed Multilevel k-Coverage Energy-Efficient Fault-Tolerant Scheduling for Wireless Sensor Networks

The expected k-coverage, prolonged network lifetime, and fault-tolerance capabilities play a vital role in the success of various application operations in Wireless Sensor Networks (WSNs), as they are the key performance indicators of WSNs. The k-coverage protocol ensures that the entire target region of interest (R\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathbb {R}}$$\end{document}) is the whole k-covered, where R\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathbb {R}}$$\end{document} can further be distributed into several target subregions. The distribution of target subregions is based on the field’s vulnerability. The value of k is higher for subregions with higher vulnerability. More explicitly, some applications request a high level of k-coverage for a portion of R\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathbb {R}}$$\end{document} that is highly vulnerable; such applications never demand a flat k-coverage for their entire R\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathbb {R}}$$\end{document}. Thus, more sensors have to be unnecessarily active to provide a flat k-coverage. Some of the sensors stop working before their expected battery lifetime, due to which the network’s overall lifetime and functionality are influenced. Therefore, instead of flat k-coverage scheduling, we propose a distributed multilevel k-coverage, energy-efficient, and fault-tolerant scheduling protocol (named DkCEFS). The average time and the communication overhead of DkCEFS is O(nlogn)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$O(n \log \, n)$$\end{document}. Simulation results proves that DkCEFS maintain the multilevel k-coverage ratio up to 40–45% compared to flat k-coverage and prolonging the average network lifetime up to 30–40% more with fault-tolerance capabilities. We also analyzed that distributed multilevel k-coverage conserve more energy than a distribution of a flat k-coverage in a stipulated network lifetime. The proof of correctness and simulation comparisons-results are presented to validate the proposed protocol’s effectiveness.