Wireless sensor networks are a set of spatially distributed autonomous nodes over a large area that can cooperatively monitor and communicate the data to the central server through wireless network [1]. Sensor networks are being utilized in many areas, including environmental conditions monitoring, military application, tracking and monitoring animals, detection of harmful animals, smart buildings, structural health monitoring, automobiles, and so on. These wireless sensor networks are capable of detecting specific conditions, such as temperature, pressure, humidity, sound, motion of objects, pollutants. In every application, security is thefundamentalfactor, and mechanisms must be designed to have a secured environment.

۱٫۱٫ Motivation

The survey in this context summarizes the application scenarios of wireless sensor networks. Here, we focus on three application scenarios – environmental wireless sensor networks, structural health monitoring, and smart building wireless sensor networks. And these three application areas are scaled to large-, medium-, and small-scale applications, respectively. The below Figure 1 shows the scheme of study. We summarize and compare pros and cons for each application. Based on this analysis and comparison summarized, we briefly investigate the open issues. The investigations raise potential research questions and hence, it gave us strong motive to conduct broad research in this area.

۱٫۲٫ Application scenarios

Wireless sensor network applications handle the sensitive data and important information, hence the wireless sensor networks are considered as critical systems. The wireless sensor networks are widely used to communicate and process data among the nodes. Over the last decade, the evolution of sensor network technology is at its peak where the applications developed focusing various operational areas. For the practical research ideology, the real-world scenarios are studied under three applications.

۱٫۲٫۱٫ Environmental wireless sensor networks

Environmental wireless sensor networks is a broad research area and it is observed that environmental sensor networks as a large application has rapid development in recent years. In this applications category, spring brook rain forest which is one of the world heritage in Australia is considered as one of the motivating application and the security issues and vulnerabilities are studied in this context [2,3]. The spring brook rain forest is the long term and the large-scale monitoring wireless sensor networks. The wireless sensor networks of spring brook rain forest is the means for tracking the restoration of bio-diversity. The major responsibilities of wireless sensor networks on spring brook rain forest are temperature monitor, wetness of the leaves, speed of the wind, soil moisture, and direction of wind. It also includes the video monitoring along with the bio-acoustic technique [4–۶].