Enhancing CSK performance in QLED-based VLC: A multi-objective optimization approach

Optimizing constellation points for Color Shift Keying (CSK) modulation in Quadrichromatic Light Emitting Diode (QLED)-based Visible Light Communication (VLC) systems poses a significant challenge. Balancing high data rates with crucial illumination quality metrics—luminous flux, Correlated Color Temperature (CCT), and Color Rendering Index (CRI)—is essential, yet often neglected in favor of communication speed. This paper introduces a novel multi-objective optimization framework utilizing the NSGA-II algorithm specifically designed for QLED-based VLC CSK constellations. Our approach simultaneously optimizes data rate (throughput), luminous flux, CCT adherence, and CRI. We demonstrate substantial performance improvements compared to both the IEEE 802.15.7 standard and prior optimization studies reported in the literature.

For 4-CSK modulation across tested CCTs (3500K, 5000K, 6500K), our method achieves gains of up to 77.28% in throughput, 349.12% in luminous flux, and 7.18% in CRI relative to the IEEE standard, while also significantly outperforming the prior study, particularly in throughput and luminous flux (e.g., achieving 66.78% vs. 77.28% throughput gain and 139.66% vs. 55% flux gain at 5000K compared to the prior study and IEEE respectively). Similar substantial advantages are observed for 8-CSK (achieving up to 64.41% throughput gain, 314.89% luminous flux gain, and 14.25% CRI gain compared to benchmarks) and 16-CSK (up to 47.80% throughput gain, 258.66% luminous flux gain, and 7.27% CRI gain).

These findings underscore the proposed framework's effectiveness in achieving a superior balance between communication performance and illumination quality compared to existing standards and methods. This research offers valuable insights for designing more efficient, high-quality, and adaptable QLED-based VLC systems suitable for diverse application requirements.