Analysis on the Compensation for the Demodulated Phase Errors Caused by Sampling Frequency Offset in OFDM Systems

Abstract

Due to the excellent spectral efficiency and inherent resistance to multipath fading effect, OFDM has been widely adopted in Digital video broadcasting-terrestrial (DVB-T). However, as a multi-carrier transmission technique, there is sampling frequency offset (SFO) in the OFDM systems, which will seriously degrade performance of demodulation by resulting in interference between adjacent sub-carriers (ICI) and demodulated phase deviation. In this paper, to achieve correction of phase errors and solve the problem that OFDM signals cannot be correctly demodulated for complex constellation when SFO exists, we propose an adaptive sampling frequency tracking and demodulated phase error compensation scheme based on synchronization symbol information of OFDM signals. Numerical results supported by simulations are provided to show that the proposed scheme in an ADSL environment indicate great performance improvement of demodulation.