Dual-Channel OOK (D-COOK) Modulation for UAV-Assisted Mixed THz/VLC Systems

This paper investigates a dual-hop UAV-assisted communications system that integrates Terahertz (THz) and Visible Light Communication (VLC) over a decode-and-forward (DF) relay that bridges the THz and VLC segments. The VLC channel is modelled to account for additive background noise and deterministic fading, while the THz link is subject to path loss, absorption loss, and pointing errors. A comparative analysis with Free Space Optics (FSO)-VLC and Radio Frequency (RF)-VLC systems highlights the superior performance of the THz-VLC system, especially at high signal-to-noise ratios (SNR), in terms of BER and outage probability. Furthermore, a novel modulation technique is proposed that enables increased data rates. Performance evaluation of the proposed modulation scheme further validates the effectiveness of the system.