Performance Evaluation of Deployable Bluetooth Low Energy Mesh Network for Monitoring System

Abstract

The development of wireless sensor network (WSN) technology has promoted automation and monitoring systems. Deploying small, low-power and lightweight nodes in the area can monitor and collect, analyze, and process information from the environment in real-time. In recent years, there have been many critical breakthroughs in Bluetooth technology. Bluetooth Low Energy (BLE) technology provides sensor networks with standardized network protocols, facilitates communication between sensor networks and heterogeneous devices, and reduces development costs. BLE Mesh enables many-to-many types of communication and opens the way to new possible applications. This thesis aims to build a prototype for an outdoor BLE mesh network monitoring system using PIR and acoustic sensors. It can detect the invasion of people by PIR sensing and compute feature vectors from the voice samples collected by the acoustic sensor. This thesis has evaluated the communication performance of the BLE Mesh network, including packet delivery rate (PDR) and round-trip time (RTT) in different network architectures, as well as the power and memory performance of nodes. The results show that the PDR maintained 100\% within 13 meters when deploying BLE Mesh nodes outdoors. Adding relaying nodes can extend the reliable communication distance, but the RTT increases by about 25 ms every hop. The battery in this system can support node work for more than 9 hours in low temperatures environment.