Multi-carrier transmission systems

US6181714A · kind A · utility

Assignee

• TELIA COMPANY AB · SE

Inventors

• Mikael Isaksson · Luleå, SE
• Magnus Johansson · Luleå, SE
• Harry Tonvall · Luleå, SE
• Lennart Olsson · Luleå, SE
• Thomas Stefansson · Luleå, SE
• Hans Ohman · Luleå, SE
• Gunnar Bahlenberg · Luleå, SE
• Anders Isaksson · Luleå, SE
• Goran Okvist · Luleå, SE
• Lis-Marie Ljunggren · Luleå, SE
• Tomas Nordstrom · Luleå, SE
• Lars-Ake Isaksson · Luleå, SE
• Daniel Bengtsson · Luleå, SE
• Siwert Hakansson · Luleå, SE
• Ye Wen · Luleå, SE

Key dates

• Filing date: Jun 1, 1999
• Grant date: Jan 30, 2001
• Expiry date: Jun 1, 2019

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04L27/2656
• WIPO field: Digital communication
• WIPO sector: Electrical engineering

Abstract

A multi-carrier transmission system using DMT. It is known to recover a receiver sample and clock from a reserved carrier, a pilot carrier having a fixed phase. A sampling clock oscillator in a receiver is then phase locked to the pilot carrier. Multi-carrier receivers, such as DMT receivers, are normally equipped with an FFT processor. A complex number representing the pilot carrier is then available from the FFT processor output. If an FFT processor is not available, a one frequency DFT processor can be provided to produce a complex estimate of the pilot carrier. In a DMT system, frame synchronization is handled separately from sampling clock synchronization, although the two processes are intimately related and frame synchronization must be acquired before sampling clock synchronization.