A Combined Batteryless Radio and WiFi Indoor Positioning System

This paper presents a design of an indoor localization system that can be used in hospital nurse calling systems. The call button of patient is batteryless and wireless. The positioning system is developed for this batteryless button. When the switch is pressed, a wireless telegram is sent to reference nodes that act like Wireless Sensor Networks (WSN). This wireless message contains the module ID and the Received Signal Strength Indicator (RSSI) value. The reference nodes or beacons forward the information gathered from target node to a central receiver attached to a computer. A program is developed to read the incoming signals to the receiver module for processing. This program calculate the distance between target node (unknown location) and each reference node (known location), and then it determines the position of the call button which held by the patient. In parallel, nurses hold smart phones, and the position is determined via WiFi-Based Positioning System (WPS). Both systems are combined and linked to the nurse calling system. Therefore, when a patient hits the batteryless button, the system will compare the patient position with nurses' positions and notify the nearest nurse. The main goal of developing such system is to decrease the time taking for the nurse to provide healthcare for patients.