A Data Aided Estimation Algorithm of Decimal Frequency Offset for OFDM System

Abstract

In recent years, orthogonal frequency division multiplexing (OFDM) technology has drawn widespread attention for its high spectral efficiency, and has doing better on combating multipath interference than traditional technology.The reason why OFDM system has high spectral efficiency is that it takes advantage of the orthogonality between sub-carriers,characteristic of which can eliminate interference of each subcarrier even when the spectrum of them overlapped.It is the demanding of orthogonality between subcarriers to demodulate signals that makes OFDM system extremely sensitive to frequency offset. Even a little frequency offset can bring inter-carrier interference.This paper studied the mechanism of formation of interference among sub-carriers, and proposed a frequency offset estimation algorithm by changing the structure of data symbols so that the data symbols can act as training sequence.The simulation results show that the proposed algorithm performs better than S.C algorithm in many aspects, such as MSE, BER, Constellation and so on.