On the Cramer-Rao Lower Bound for Frequency Correlation Matrices of Doubly Selective Fading Channels for OFDM Systems

TL;DR

This paper derives the CRLB and maximum likelihood estimator for frequency correlation matrices in doubly selective fading channels for OFDM, highlighting the dominant effect of sample size on estimation accuracy.

Contribution

It provides analytical expressions for the CRLB and ML estimator specific to OFDM channels with doubly selective fading, a novel contribution in this context.

Findings

Sample size significantly impacts mean square error

SNR and Doppler spread have negligible effect on estimation accuracy

Analytical and numerical results validate the derived expressions

Abstract

The analytic expression of CRLB and the maximum likelihood estimator for the sample frequency correlation matrices in doubly selective fading channels for OFDM systems are reported in this paper. According to the analytical and numerical results, the amount of samples affects the average mean square error dominantly while the SNR and the Doppler spread do negligibly.