Frequency Offset Estimation and Training Sequence Design for MIMO OFDM

TL;DR

This paper proposes a novel method for estimating carrier frequency offset in MIMO OFDM systems by designing special training sequences, improving estimation accuracy over frequency selective channels.

Contribution

It introduces a new training sequence design based on Chu sequences and a combined approach for integer and fractional CFO estimation in MIMO OFDM systems.

Findings

Accurate CFO estimation demonstrated through simulations

Training sequences ensure identifiability of CFO parameters

Proposed sequences outperform existing methods in robustness

Abstract

This paper addresses carrier frequency offset (CFO) estimation and training sequence design for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems over frequency selective fading channels. By exploiting the orthogonality of the training sequences in the frequency domain, integer CFO (ICFO) is estimated. {With the uniformly spaced non-zero pilots in the training sequences} and the corresponding geometric mapping, fractional CFO (FCFO) is estimated through the roots of a real polynomial. Furthermore, the condition for the training sequences to guarantee estimation identifiability is developed. Through the analysis of the correlation property of the training sequences, two types of sub-optimal training sequences generated from the Chu sequence are constructed. Simulation results verify the good performance of the CFO estimator assisted by the proposed training sequences.