ML Estimation of Time and Frequency Offset Using Antenna Diversity in OFDM Systems

This paper presents the joint maximum likelihood (ML) time and frequency offset estimator exploiting antenna diversity in orthogonal frequency division multiplexing (OFDM) systems. Redundant information contained within the cyclic prefix (CP) is used and furthermore, we propose a new correlation coefficient for ML estimation and can obtain diversity gain from several received antenna signals. The method is efficient in an environment having a low signal to noise ratio (SNR) and multipath channel by combining the received signals from antennas in an OFDM system. In this paper we demonstrate an example of ML estimation from two received antenna signal.