Accurate time synchronization is essential for Internet of Things (IoT) systems, where multiple distributed nodes must share a common time base for coordinated sensing and data fusion. However, conventional synchronization approaches suffer from nondeterministic transmission latency, limited precision, or restricted bidirectional functionality. This paper presents a protocol-independent wireless timer synchronization method that exploits radio timeslots to transmit precisely timestamped beacons in a proprietary radio mode. By decoupling synchronization from upper-layer packet retransmissions and leveraging hardware-timed radio events, the proposed approach significantly reduces scheduling uncertainty and achieves nanosecond-level synchronization accuracy. Comprehensive experiments evaluate the impacts of synchronization frequency, RSSI, BLE connection interval, and throughput on synchronization performance. The results demonstrate that an optimal synchronization frequency of 1000 Hz yields an approximately 20 ns delay in the absence of communication stack activity while maintaining sub-500 ns accuracy under most realistic BLE traffic conditions. Furthermore, larger connection intervals, lower application throughput, and higher RSSI consistently improve synchronization quality by reducing radio resource contention and packet loss. The proposed scheme provides a general and high-precision synchronization solution suitable for resource-constrained IoT systems.

翻译：精确的时间同步对于物联网系统至关重要，其中多个分布式节点必须共享统一时间基准以实现协同感知与数据融合。然而，传统同步方法存在传输延迟不确定、精度受限或双向功能受限等问题。本文提出一种协议无关的无线定时器同步方法，该方法利用专有无线电模式下的无线时隙传输精确时间戳信标。通过将同步机制与上层数据包重传解耦，并利用硬件定时无线电事件，所提方法显著降低了调度不确定性，实现了纳秒级同步精度。综合实验评估了同步频率、RSSI、BLE连接间隔及吞吐量对同步性能的影响。结果表明：在无通信栈活动时，1000 Hz最优同步频率可实现约20 ns延迟，且在大多数实际BLE流量条件下保持500 ns以下精度。此外，增大连接间隔、降低应用吞吐量及提高RSSI可通过减少无线电资源竞争与丢包持续改善同步质量。该方案为资源受限的物联网系统提供了一种通用高精度同步解决方案。