Comparative analysis of RF semi-quantum key distribution (QKD) under noisy RF channels

Abstract This paper presents a comparative investigation of two quantum communication architectures – standard quantum key distribution (QKD) and semi-quantum key distribution (SQKD) – operating over noisy RF channels and enhanced with quantum phase estimation (QPE) feedback for phase noise mitigation. In QKD, both communicating parties are fully quantum-capable, while in SQKD, one party is restricted to limited classical-level quantum operations. The study evaluates performance under realistic noise models incorporating depolarizing noise, thermal relaxation, and Gaussian-distributed phase noise, examining the impact of QPE pilot configurations on phase tracking, residual error, and error rates. Simulation results reveal that while QPE feedback significantly improves robustness in both architectures, the SQKD configuration exhibits slower convergence, higher residual errors, and more variable key error rates due to the classical party’s limited corrective capabilities. These findings highlight the trade-offs between hardware complexity and performance in quantum-secured RF communication systems.