# A Low Energy IoT Application Using Beacon for Indoor Localization  
[PERSON]  
1 Department of Energy, Polytechnic of Milan, 20156 Milan, Italy2 Department of Industrial Engineering, University of Salerno, 84084 Fisciano, Italy; [EMAIL_ADDRESS] (E.A.A. ); [EMAIL_ADDRESS] (V.G. )3 Department of Electrical Engineering and Information Technologies, University of Naples \"Federico II\", 80126 Naples, Italy; [EMAIL_ADDRESS] Department of Electrical Engineering, Universidad Tecnica de Manabi, Portoviego 130105, Ecuador; [EMAIL_ADDRESS] Correspondence: [EMAIL_ADDRESS]  
E.A.A. the transfer of any type of information between two or more points that are not physically connected to each other. The developments in the field of communication and the advent of the Internet of Things have led to a wide range of different services in order to improve the quality of service (QoS) provided to the user [7,8]. Among these, services based on internal location are of interest. Although the GPS--acronym for Global Position System--is a fairly accurate positioning system for the estimation of position, in an indoor environment it is unusable, due to the scarce or even non-existent presence of a satellite signal [9,10]. To solve the problem of indoor localization, techniques have been adopted that mainly concern the IEEE 802.11 standard and, in particular, the b and g releases (commercially known as Wi-Fi). Indoor localization, compared to the outdoor one, is much more challenging due to the presence of a wide range of obstacles that affect the result of the localization [11]. In order to design a functioning indoor localization system, it is necessary to take advantage of everything that is currently present in the state of the art. Localization in an indoor environment turns out to be an essential and important research problem of the Internet of Things. Since smart objects can be identified and equipped with wireless communication capabilities, it is possible to locate them in a certain environment [12]. Location-based IoT applications are exploited to monitor objects and people for resource management, for agriculture, and for health care. Unlike what happens with an outdoor positioning system, where the LTE network is used in addition to GPS for a more precise location, for an indoor location system, it is necessary to develop a hardware-software set that can simulate the GPS function within a delimited and closed space. The idea behind this localization system is to exploit \"smart\" objects, deriving precisely from the IoT, in order to define an infrastructure system capable of reading and returning the required result. For this purpose, the IoT uses some detection devices, such as sensors, RFID tags and Bluetooth devices. The wireless location systems basically imply the presence of at least three points of reference from which to obtain useful information for the final goal, distributed in fixed positions known a priori, of at least one mobile node. The technologies used in these systems are highly heterogeneous; among the most used are Wi-Fi, ultrasound, radio frequency identification (RFID) and Bluetooth communication [13]. To date, however, there is no dominant technology that can be used in all cases. Each technology that an indoor localization system can use processes, through various techniques, the data received from the sensors in a different way. However, it is possible to divide and manage a generic localization system essentially through two phases:  
1. Data collection: In this phase, all useful information is collected from the reference sensors and then processed to provide the data actually requested (the final position);
2. Localization: The devices that act as transmitters are affected by the surrounding environment and any obstacles. This phase is used to improve the accuracy of the position estimation, taking into account any systematic errors due to any interference. The aim of this paper is to provide a system to detect people in an indoor location, using BLE technology.