20-µs Accuracy Time-Synchronization Method using Bluetooth Low Energy for Internet-of-Things Sensors
Masayasu Harada, Shintaro Izumi, Ryosuke Kozeni, Yukiko Yoshikawa, Ishii Toru, Hiroshi Kawaguchi, Shohei Uemura, Kaname Araki · 2022
This paper presents a low-power and accurate time-synchronization method for Internet-of-Things (IoT) sensors. Time synchronization between the base station and sensor nodes is important for realizing synchronized measurement and data collection from multiple sensor nodes. The proposed method is implemented within the application layer of the Bluetooth Low Energy protocol, and it only requires a 32.768-kHz real-time clock and an active flag of a power amplifier in the transmission circuit and a low-noise amplifier in the receiver circuit. This limited hardware requirement allows for the implementation of commercially available communication modules. The synchronization performance was evaluated with eight peripheral nodes and one central node, and the measurement results indicate that a 20-µs synchronization error was achieved on average for all the eight peripherals.