Frame Synchronization Exploiting Cauchy Distribution in DMT-Based xDSL Modems

This letter considers frame synchronization in nonsynchronized sampling discrete multi-tone (DMT) based asymmetric digital subscriber line (ADSL)/very high speed DSL (VDSL) systems in the presence of timing error. We propose a frame synchronization method which is based on the observation that the normalized correlation between two sequences separated by the FFT length is Cauchy random variable. The proposed approach uses less number of correlators, reducing computational complexity as well as demodulation delay than a previous approach [1]. Therefore, ADSL/VDSL modems can be more power efficient and computationally less complex via the proposed frame synchronization method. Simulation results demonstrate the effectiveness of the proposed approach, comparing with the previous approach. key words: Cauchy distribution, sampling frequency offset, sampling phase offset, non-synchronized sampling