1.
Liu, Xin; Xu, Chao; Ng, Soon Xin; Hanzo, Lajos
OTFS-Based CV-QKD Systems for Doubly Selective THz Channels Journal Article
In: IEEE Transactions on Communications, vol. 73, no. 8, pp. 6274–6289, 2025, ISSN: 1558-0857.
Abstract | Links | BibTeX | Tags: Array signal processing, continuous variable quantum key distribution (CV-QKD), Faces, Fading channels, low-density parity check (LDPC), multiple-input multiple-out (MIMO), OFDM, Orthogonal frequency division multiplexing (OFDM), orthogonal time frequency space (OTFS), Parity check codes, Random variables, secret key rate (SKR), Symbols, Terahertz (THz), Terahertz communications, Time-frequency analysis, Vectors
@article{liu_otfs-based_2025,
title = {OTFS-Based CV-QKD Systems for Doubly Selective THz Channels},
author = {Xin Liu and Chao Xu and Soon Xin Ng and Lajos Hanzo},
url = {https://ieeexplore.ieee.org/document/10857395},
doi = {10.1109/TCOMM.2025.3535889},
issn = {1558-0857},
year = {2025},
date = {2025-08-01},
urldate = {2025-10-08},
journal = {IEEE Transactions on Communications},
volume = {73},
number = {8},
pages = {6274–6289},
abstract = {The feasibility of continuous variable quantum key distribution (CV-QKD) is considered in the Terahertz (THz) band, experiencing time-varying and frequency-selective fading. Advanced multi-carrier modulation is required for improving the secret key rate (SKR). However, the hostile quantum channel requires powerful classical channel coding schemes for maintaining an adequate reconciliation performance. Against this background, for the first time in the open literature, we propose a multi-carrier quantum transmission regime that incorporates both orthogonal frequency division multiplexing (OFDM) and orthogonal time frequency space (OTFS) transmission over doubly selective fading THz channels. Furthermore, we propose a modified multi-dimensional reconciliation algorithm for CV-QKD, facilitating the integration of OFDM/OTFS quantum transmission with low-density parity check (LDPC) coded key reconciliation. Moreover, we harness multiple-input multiple-output (MIMO) beamforming for mitigating the severe THz path loss. Our SKR analysis results demonstrate that the proposed OTFS-based and LDPC-assisted CV-QKD system is capable of outperforming its OFDM counterpart in mobile wireless scenarios. Moreover, we also demonstrate that increasing the MIMO dimension reduces the transmission power required for achieving the secure transmission distance target.},
keywords = {Array signal processing, continuous variable quantum key distribution (CV-QKD), Faces, Fading channels, low-density parity check (LDPC), multiple-input multiple-out (MIMO), OFDM, Orthogonal frequency division multiplexing (OFDM), orthogonal time frequency space (OTFS), Parity check codes, Random variables, secret key rate (SKR), Symbols, Terahertz (THz), Terahertz communications, Time-frequency analysis, Vectors},
pubstate = {published},
tppubtype = {article}
}
The feasibility of continuous variable quantum key distribution (CV-QKD) is considered in the Terahertz (THz) band, experiencing time-varying and frequency-selective fading. Advanced multi-carrier modulation is required for improving the secret key rate (SKR). However, the hostile quantum channel requires powerful classical channel coding schemes for maintaining an adequate reconciliation performance. Against this background, for the first time in the open literature, we propose a multi-carrier quantum transmission regime that incorporates both orthogonal frequency division multiplexing (OFDM) and orthogonal time frequency space (OTFS) transmission over doubly selective fading THz channels. Furthermore, we propose a modified multi-dimensional reconciliation algorithm for CV-QKD, facilitating the integration of OFDM/OTFS quantum transmission with low-density parity check (LDPC) coded key reconciliation. Moreover, we harness multiple-input multiple-output (MIMO) beamforming for mitigating the severe THz path loss. Our SKR analysis results demonstrate that the proposed OTFS-based and LDPC-assisted CV-QKD system is capable of outperforming its OFDM counterpart in mobile wireless scenarios. Moreover, we also demonstrate that increasing the MIMO dimension reduces the transmission power required for achieving the secure transmission distance target.