Precursor ISI-free frame synchronization for DMT VDSL system

Abstract

A new modified maximum likelihood (ML) algorithm for frame synchronization in discrete multitone VDSL transmission system is presented. Computer simulation results are included to show its improvement in Et/N-0 of each tone in the received data. This algorithm estimates the frame boundary at the initial transition edge rather than at the middle peak of a shortened twisted-pair channel response. The timing margin degradation caused by precursor intersymbol interference (ISI) can be reduced significantly, especially at the sub-channel loaded with more bits.