The light-emitting diode (LED) is the major source of nonlinearity in LED communications,
and the nonlinearity needs to be effectively modeled and thereby mitigated
through predistortion or postdistortion to avoid degradation of communication performance.
A memory polynomial is often used for LED nonlinearity modeling and mitigation in the literature.
However, the estimation of memory polynomial coefficients suffers from numerical instability,
resulting in inaccurate modeling and poor performance in nonlinearity mitigation. In
this paper, we propose an orthogonal polynomial-based nonlinearity modeling and mitigation
technique for LED communications with pulse amplitude modulation (PAM) signaling
and show that the proposed technique significantly outperforms the conventional memory