Multi-carrier transmission systems

US6493395B1 · kind B1 · utility

Assignee

• STMICROELECTRONICS N.V. · NL

Inventors

• Mikael Isaksson · Luleå, SE
• Magnus Johansson · Luleå, SE
• Harry Tonvall · Luleå, SE
• Lennart Olsson · Luleå, SE
• Tomas 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 2, 1999
• Grant date: Dec 10, 2002
• Expiry date: Jun 2, 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 orthogonal carriers with high order QAM constellations for the transmission of multiple bits per carrier and symbol. Such systems place high demands on the synchronization of the receiver with the transmitter. The maximum permitted deviation from exact synchronization is usually a small fraction of a sampling interval. A reserve carrier, the pilot carrier, which is given a fixed phase, is usually used as the reference to achieve this high accuracy. The receiver sampling clock oscillator is phase locked to the pilot carrier. It is therefore necessary to estimate the phase of the pilot carrier. Using a bandpass filter to recover the pilot carrier, regardless of the frame structure of the DMT signal, does not eliminate the influence of neighboring carriers on the pilot carrier.