مقاله انگلیسی رایگان در مورد پروتکل های مبتنی بر پوشش برای شبکه های حسگر بی سیم – الزویر 2018

A wireless sensor network (WSN) consists of a group of energy-constrained sensor nodes with the ability of both sensing and communication, which can be deployed in a field of interest (FoI) for detecting or monitoring some special events, and then forwarding the aggregated data to the designated data center through sink nodes or gateways. In this case, whether the WSN can keep the FoI under strict surveillance and whether the WSN can gather and forward the desired information are two of the most fundamental problems in wireless sensor networks that need to be solved. Therefore, preserving network connectivity while maximizing coverage by using the limited number of energy constrained nodes is the most critical problem for the deployment of WSNs. In this survey article, we classify and summarize the state-of-the-art algorithms and techniques that address the connectivity-coverage issues in the wireless sensor networks.

Introduction

Wireless sensor networks (WSNs) have gained a considerable attention in the recent years [1, 2]. The development of modern sensing and wireless communication technologies have greatly promoted the development of energy- efficient micro sensing equipments with both sensing and wireless communication abilities, which is the furtherance of developing WSNs [3]. The objective of the deployment of the WSN is to monitor a given field of interest (FoI) or keep a given target under strict surveillance. However, due to the limited size and battery capacity, both computational and communication capacities of the sensor nodes are limited [4]. Hence, in order to achieve the expected objective, multiple sensor nodes need to cooperate. Typically, a large-scale WSN that consists of thousands of sensor nodes is deployed to cover a given FoI by either random or deterministic method. The connected WSNs can accomplish many complicated tasks. Moreover, by exploiting the communication capacity of the sensor nodes, the WSN can consist a wireless communication network to transmit the gathered data which eliminates the dependency of the complicated wired communication backbone that is hard to be deployed in the remote area. Moreover, by exploiting its easedeployment property, the WSN is widely adopted in very broad applications, e.g., the surveillance of military activities, boundary control, and industrial and agricultural monitoring, etc [5]. As aforementioned, the existing deployment strategies of WSNs are categorized into two main classes: the deterministic ones and the random ones. For the deterministic method, the deployed position of each sensor node is predefined for a specific FoI. It can achieve the system objective more efficiently. However, if the WSNs are deployed in the remote area and the environment can be very hazardous to the human safety, e.g., the battlefield, volcano, etc, the manual/deterministic deployment strategies of WSNs may not be adopted. In this case, the random deployment strategies of WSN could be an applicable option, e.g., paradropped by the airplane. Then, the deployed WSN needs to automatically work for weeks or months. During the working period, the battery replacement may not be applicable [3]. Hence, the energy preserving problem has to be considered when the WSN-based system is being designed. In order to prolong the lifetime of the network, utilizing the WSN in an energy efficient method is essential to facing the strict energy constraint in sensor nodes [6]. Furthermore, there are another two important factors that affects the deployment of an efficient WSN, i.e., find optimal node deployment/area coverage strategies and efficient connectivity control techniques. Once the nodes are deployed, they need to sense and detect the desired events from the given FoI, and then generate corresponding data for the detected events.