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arXiv · 2609.20542

Technical Report OFDM-Assisted Simultaneous Quantum and Classical THz Communications

Xin Liu·Chao Xu·Soon Xin Ng·Mohammed El-Hajjar·Phuc V. Trinh·Shinya Sugiura·Lajos Hanzo
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Abstract

The feasibility of cost-effective simultaneous quantum and classical communication (SQCC) transmitting both the quantum key and classical information via a superimposed coherent state is investigated both in optical and Terahertz (THz) bands. Since the existing THz SQCC schemes assume single-carrier (SC) transmission over flat fading channels, we embark on investigating SQCC in realistic frequency-selective multipath THz fading channels. We then propose an orthogonal frequency division multiplexing (OFDM) based SQCC system for time-invariant frequency-selective THz scenarios, supported by low-density parity-check coded (LDPC) multidimensional QKD reconciliation schemes. Our simulation results demonstrate that the OFDM-based SQCC scheme is capable of achieving a practical secret key rate (SKR) over a wide range of power sharing scenarios between the classical and quantum signals. By contrast its single-carrier counterpart requires the classical signal to be at least 100 times stronger than the quantum signal in THz SQCC.

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Xin Liu, Chao Xu, Soon Xin Ng, Mohammed El-Hajjar, Phuc V. Trinh, Shinya Sugiura, Lajos Hanzo. 2026-09-17. Technical Report OFDM-Assisted Simultaneous Quantum and Classical THz Communications. https://arxiv.org/abs/2609.20542

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