Pulse-Based Clock Synchronization and Physical Layer Communication in Wireless Sensor Networks

Clock synchronization is a critical technology in wireless sensor networks (WSNs), providing an essential foundation for data fusion, event scheduling, and collaborative operations among network nodes. However, existing clock synchronization methods face challenge of random delay in practical applications. To address these issues, this paper first proposes a pulse-based physical layer clock synchronization method, which can achieve the synchronization directly at the physical layer, thereby avoiding the random delays introduced by the upper-layer network. Specifically, the high-precision phase offset estimation between the reference node and the slave nodes is first accomplished under the one-way dissemination mechanism by leveraging the correlation property of pulse sequences. On this basis, the estimated clock information is quantized and encoded into pulse signals for transmission using pulse position modulation (PPM) technology, thereby enabling synchronization and communication between any two slave nodes at the physical layer. Simulation results demonstrate that our proposed pulse-based method significantly improves estimation accuracy, achieving the mean square error (MSE) of approximately −45 dB in synchronization precision. Compared to the benchmark schemes, the proposed pulse-based physical layer scheme exhibits notable advantages in system performance: it can reduce the MSE by approximately 16 dB compared to Benchmark Scheme 1 and by approximately 10 dB compared to Benchmark Scheme 2.