FTN-based cooperative NOMA in VLC: impact of channel parameters

Abstract This paper evaluates an FTN (faster-than-Nyquist)-based Cooperative Non-Orthogonal Multiple Access (C-NOMA) system in a Visible Light Communication (VLC) channel. The system employs Decode-and-Forward (DF) relaying to improve link reliability, user connectivity, and spectral efficiency. MATLAB simulations are conducted to evaluate the BER performance under varying SINR levels, transmit power, channel conditions, receiver field of view (FOV), optical wavelength, and FTN acceleration factor ( β ). The results indicate that the BER decreases monotonically with increasing SINR and transmit power, achieving an improvement of nearly 99.9%, from 10 −1 to 10 −4 , at a transmit power of 40 dBm with β = 0.6. A close agreement between analytical expressions and simulation results is observed, thereby validating the accuracy of the proposed model. Furthermore, the impact of the FTN acceleration factor ( β ) on the SINR versus spectral efficiency (SE) trade-off is investigated through simulations. Compared to a conventional Nyquist-based NOMA-VLC, the FTN-based cooperative NOMA achieves similar BER with lower SINR, demonstrating enhanced power efficiency and robustness to FOV variations. Overall, FTN signaling with cooperative NOMA improves both BER and spectral efficiency, making it a promising approach for future wireless systems.