Low-Power High-Accuracy Time Synchronization Using PPI for Bluetooth-Based IoT Systems

In this paper, we propose a low-power, high-accuracy time synchronization system for Bluetooth-based communication. Building upon our previous research on MicroSync, this system achieves high precision by utilizing the programmable peripheral interconnect (PPI) of nRF52840 for communication timing detection and hybrid timer synchronization. PPI is a hardware feature that enables peripherals to directly cooperate without involving the CPU, thereby eliminating unstable delays caused by interrupt-based implementations. Hence, the proposed method achieves a time synchronization accuracy of 107.6 ns with a standard deviation of 122.7 ns at a power consumption of 244.1 μW. This represents a 60.5% improvement in synchronization accuracy compared to MicroSync without increasing power consumption. By leveraging PPI, the proposed method demonstrates high synchronization accuracy while maintaining energy efficiency, making it suitable for Bluetooth-based IoT systems that require both low power and high precision.