Autonomous synchronization of a DMT-VDSL system in unbundled networks
2002 (English)In: IEEE Journal on Selected Areas in Communications, ISSN 0733-8716, E-ISSN 1558-0008, Vol. 20, no 5, 1055-1063 p.Article in journal (Refereed) Published
We present an algorithm that autonomously synchronizes all DMT-Zipper based VDSL modems in an unbundled access network, solving the problem with nonorthogonal NEXT that appears in systems with unsynchronized modems. The algorithm we present runs autonomously in each VDSL-modem in the central office or in the street cabinet. We determine the other modems ' relative frame offsets by exploiting their NEXT signal using the inherent cyclic redundancy found in DMT signals. By estimating the relative frame offsets of the other users, we can adjust a given user's own frame-timing relative to the mean of the others. With our method all modems in the network will be synchronized to within a small fraction of the total DMT frame-length, suppressing the nonorthogonal NEXT to a level far below the background noise-floor. This means that we can achieve the same performance in an unbundled access network without any master clock reference as in a system where all modems are perfectly synchronized using a master clock. Index Terms-Discrete multitone, frame synchronization, subscriber loops.
Place, publisher, year, edition, pages
2002. Vol. 20, no 5, 1055-1063 p.
Research subject Signal Processing
IdentifiersURN: urn:nbn:se:ltu:diva-13669DOI: 10.1109/JSAC.2002.1007386Local ID: ceec9a60-12c6-11dd-ada4-000ea68e967bOAI: oai:DiVA.org:ltu-13669DiVA: diva2:986622
IEEE International Conference on Communications : 11/06/2001 - 14/06/2001
Validerad; 2002; 20080425 (ysko)2016-09-292016-09-29Bibliographically approved