Subscriber line transmission systems

US6738440B1 · kind B1 · utility

Assignee

• STMICROELECTRONICS N.V. · NL

Inventors

• Mikael Isaksson · Luleå, SE
• Magnus Johansson · 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
• Daniel Bengtsson · Luleå, SE
• Sven-Rune Olofsson · Älvsbyn, SE
• Joachim Johansson · Älvsbyn, SE
• Per Ola Börjesson · Fontanafredda, IT
• Niklas Grip · Luleå, SE
• Richard Nilsson · Luleå, SE
• Frank Sjöberg · Luleå, SE
• Sarah Wilson · Ponteland, GB
• Per Ödling · Ayacucho, PE

Key dates

• Filing date: Dec 27, 2000
• Grant date: May 18, 2004
• Expiry date: Dec 27, 2020

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04L27/2647
• WIPO field: Digital communication
• WIPO sector: Electrical engineering

Abstract

A RFI canceller, for use in a subscriber line system using multi-carrier modulation, measures a RFI disturbance in carriers falling within a band of frequencies causing the RFI. The RFI ingress into carriers outside the band of frequencies is estimated, and an error correcting signal derived from the estimation of the RFI ingress is subtracted from a received signal. The subscriber line system may be a VDSL system and the multi-carrier modulation may be DMT. The RFI canceller includes a demodulator for demodulating an incoming data stream to provide a first parallel data stream. A parallel to serial convertor converts the first parallel data stream to a first serial data stream. A digital to analogue convertor converts the first serial data stream to a first analogue signal. An analogue RFI canceller circuit combines the analogue signal with an analogue error correcting signal, to produce a second analogue signal. An analogue to digital convertor converts the second analogue signal to a second serial data signal. A serial to parallel convertor converts the second serial data stream to a second parallel data stream. A modulator modulates the second parallel data stream onto a multip…