Robust non data-aided frequency offset estimation technique

A new technique to recover the carrier frequency offset of OFDM systems is proposed. The proposed technique does not require cyclic prefix, pilot signals, training symbols, or any other supplementary data, this will significantly improve the system power and bandwidth efficiency. The proposed algorithm exploits the interference that results due the loss of orthogonality between subcarriers where the variance of the resulted interference is proportional to the carrier frequency offset. The proposed technique does not require prior fine symbol synchronization and it is capable of estimating the carrier offset at E/sub b//N/sub o/ as low as -3 dB with symbol timing offset that is less than or equal to 10% of the symbol duration.

II. INTRODUCTION

Orthogonal frequency division multiplexing (OFDM) a modulation technique employs orthogonal subcarriers modulated by parallel data streams [1]. Compared to single carrier systems, OFDM shows significant immunity in multipath and impulsive noise channels, and possesses high bandwidth efficiency due to the overlapping of the subcarriers spectra. Due to these advantages, OFDM was adapted as the modulation scheme for audio digital broadcasting (ADB) system [2] and is also proposed as the terrestrial HDTV transport in Europe [3], and is being investigated for other wireless applications such as digital broadcast television and mobile communication systems, as well as for broadband digital communication on existing copper networks.