Adaptive Modulation Control in Visible-Light Communication Systems Based on a Joint Analysis of the Hurst Exponent and Local Estimation of the Signal-to-Noise Ratio Derivative. Part 1. Theoretical Foundations and Algorithm Development

An adaptive modulation control algorithm for visible-light communication systems is proposed. It utilizes a combined analysis of the Hurst exponent and a local estimate of the signal-to-noise ratio derivative. The algorithm utilizes asymmetric switching logic: modulation order upshifts are permitted only when the conditions of a positive local derivative estimate and high time series persistence are simultaneously met, while downshifts are performed immediately upon detection of a directional degradation. The algorithm’s threshold parameters are substantiated by analyzing speed-gain heat maps constructed for experimental scenarios. The proposed algorithm reduces the number of modulation order switches relative to the classical threshold method by 7.1 to 81.2%, depending on the channel dynamics.

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