An Identity of Hankel Matrices Generated from the Moments of Gaussian Distribution
Sha Hu
TL;DR
The paper addresses exact identities between Hankel matrices generated from Gaussian moments and their use in optimizing a nonlinear distortion function for a maximum-likelihood receiver. It derives closed-form Cholesky-based decompositions and reveals a commuting identity via Hermite-polynomial structure, recasting the optimization as a spectral problem. The key contributions are (i) a commuting identity that reduces the transformed Hankel product to a scalar multiple of a diagonal matrix, (ii) explicit factorizations of the Hankel matrices in terms of diagonal scaling, and (iii) the result that the maximal gain is $G = N/\sigma^2$ with the optimal distortion function being the $N$-th Hermite polynomial $H_N(s)$. These findings provide exact, scalable tools for NL distortion optimization in Gaussian channels and highlight deep connections between Hankel structure and Hermite polynomials.
Abstract
In this letter, we proved a matrix identity of Hankel matrices that seems unrevealed before, generated from the moments of Gaussian distributions. In particular, we derived the Cholesky decompositions of the Hankel matrices in closed-forms, and showed some interesting connections between them. The results have potential applications in such as optimizing a nonlinear (NL) distortion function that maximizes the receiving gain in wireless communication systems.
