Symbol synchronisation in a DMT system with crosstalk interference

摘要

In a DMT telecommunciations transmission system having at least two VDSL systems, each comprising a pair of modems, and belonging to a single binder group common to both VDSL systems, a method is described for keeping DMT frames aligned to the same frame timing. In this way, orthogonality holds and adjacent carriers can be used for different transmission directions without an capacity loss due to NEXT cross-talk. The steps are: estimating the time mis-alignment and power of cross-talk DMT signals added to a received DMT signal. The estimate is used by the modem to synchronise its own frame timing to a main cross-talker's frame timing auto-correlation is used on the received signal and a delayed copy of the received signal correlation maxima determine the frame boundaries of different DMT components of the received signal.