Time and Frequency Synchronization for Power Line OFDM Systems with Colored Noise

A pilot aided joint symbol timing and frequency offset estimator for OFDM systems over power line channel (PLC) with colored noise is proposed in this paper. In the proposed estimator, the received time domain OFDM samples are first divided into groups where noise samples are approximately independent. Initial maximum likelihood (ML) based symbol timing and frequency offset estimates are obtained based on each group and final estimate is then derived by combining the initial estimates. We further simplify the proposed estimator to a practical one which does not require the knowledge of PLC fading profile, noise profile and signal-to-noise-ratio (SNR). The simulation results show that, under the presence of colored noise, the proposed practical symbol timing estimator achieves performance gain in terms of correct synchronization probability, around 2 dB at SNR=15 dB, and with improved mean square error (MSE) performance, compared to the widely adopted estimator in. With the knowledge of the statistics of colored noise, another algorithm is also proposed to further improve the estimation performance.