A Survey of Localization Systems in Internet of Things

With the rapid development in wireless technologies and the Internet, the Internet of Things (IoT) is envisioned to be an integral part of our daily lives. Localization-based services are among the most attractive applications related to the IoT. They are actually, thanks to the deployment of networks of sensors, able to collect and transmit data in order to determine the targets position. A plethora of localization systems are proposed in the literature. These localization systems are based on different positioning approaches, different techniques and different technologies, making them appropriate for some applications and inappropriate for other applications. This survey provides a general overview of the localization in Wireless Sensor Networks (WSN) and surveys technical details related to approaches and algorithms of various important localization techniques using different technologies. Based on the localization approaches, we propose to classify the localization systems to centralized, distributed and interactive. Considering the techniques of localization, we classify them to distance measurement, angle measurement, arear measurement and hop-count measurement based. Finally, Depending on the manner of the wireless devices interaction with the target, we classify the localization systems to two categories: device-based and device-free systems. In device-based techniques, localization is linked to the target, and localization is determined thanks to the cooperation with other deployed wireless devices. Whereas in the device-free systems, the target does not include any wireless device according to the localization. We compare exhaustively each system in terms of precision, cost, evolution and energy efficiency. Furthermore, we show the importance of localization in modern IoT application such as smart city, smart transportation and mobility. In this concern, we provide an overview of the main challenges of localization in IoT exposed recently in the literature. Finally, we suggest in this paper some future directions in localization studies. This paper intends to help new researchers in the field of localization and IoT by providing a comprehensive survey on recent advances in this field.