Multi-Horizon Delay Asymmetry Prediction and Compensation for IEEE 1588 Precision Time Protocol on Copper and Fiber...

IEEE 1588 Precision Time Protocol (PTP) synchronization accuracy is degraded by delay asymmetry in physical links. Accurate prediction and compensation of this asymmetry are essential for high-precision timekeeping. This paper presents a multi-horizon delay asymmetry prediction framework validated on a cesium-referenced testbed. The experimental platform integrates a cesium atomic clock (frequency stability <5×10-12), a Syncedge C10 PTP analyzer, and an RK3568 embedded TimeReceiver, providing hardware-timestamped ground-truth measurements over 24 h periods on both copper and fiber links under real operating conditions. A unified multi-output encoder architecture is compared against per-horizon recurrent models and classical baselines to predict delay asymmetry at five future horizons (h∈{1,2,4,8,16}, corresponding to 0.125-2.0 s ahead). On copper links at an 8 s observation window, the unified model achieves a mean absolute error of 2.15 ns and an R2 of 0.714 at the nearest horizon, statistically tied with the best per-horizon model (2.16 ns, R2=0.713) while using 1.9-6.1× fewer total parameters (655 K vs. 1.2-4.0M). On fiber links, all models achieve comparable accuracy with an MAE of 2.16-2.18 ns. The method requires ground-truth labels from a calibrated 1PPS or cesium reference; both training and inference require the same physical link and environmental conditions. Generalization to other settings remains untested.