Phase noise is an unsolved, limiting factor for high frequency communications envisioned for 6G. Proposed herein are phase-tracking reference signals embedded in each guard-space of a message. The receiver can recalibrate the phase noise, and amplitude noise as well, with based on each guard-space reference signal, thereby providing extremely localized noise compensation including amplitude and phase distortions and including rapidly-varying frequency-dependent distortions characteristic of interference, on a symbol-by-symbol basis, at zero cost in message throughput and transmission power. The normal functions of a cyclic prefix in the guard-space can be provided by tailoring the guard-space reference signal, as detailed herein. Examples show how guard-space reference signals provide a fault-mitigating capability that is enabling to 6G mmWave objectives.