Investigation on the Performance of Spiral Constellation in Visible Light Communication

In this letter, we investigate the application of spiral constellations to visible light communication. As a type of circular constellation, the spiral constellation can be straightforwardly constructed using a spiral expression. The proposed spiral constellation is optimized with full consideration of the entire operating range of the light-emitting diode. It achieves superior noise resilience due to its larger average minimum Euclidean distance and exhibits enhanced robustness against nonlinearity by virtue of its lower peak-to-average power ratio. Moreover, we propose a bit-to-symbol mapping algorithm to approximate the Gray coding gain, accounting for the non-uniform Euclidean distances between adjacent constellation points. Extensive experiments are conducted to evaluate the performance of the proposed constellation. Experimental results demonstrate that the available ranges of the driving peak-to-peak voltage and bias current are significantly extended, which clearly validates the superiority of the proposed scheme.