Frequency correction for a multicarrier system

US7324599B2 · kind B2 · utility

Assignee

• Telefonaktiebolaget LM Ericsson (Publ) · SE

Inventors

• Georg Frank · Nürnberg, DE
• Mathias Pauli · Koblenzer Straße, DE
• Udo Wachsmann · Schwabach, DE
• Peter Schramm · Erlangen, DE

Key dates

• Filing date: Jan 5, 2004
• Grant date: Jan 29, 2008
• Expiry date: Oct 6, 2025

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04L27/2679
• WIPO field: Digital communication
• WIPO sector: Electrical engineering

Abstract

In order to correct frequency deviations of signals in a multicarrier system, such as a OFDM-system, the present invention provides a frequency tracker and a method to operate the same. The frequency tracker is based on a decision directed digital phase locked loop exhibiting a predictive character. On the basis of an estimated phase offset for a received signal (signal component, signal symbol) a predicted phase offset is calculated and applied to the signal (signal component, signal symbol). Further, received signals (signal components, signal symbols) are sampled and for each sample a sample phase offset to be corrected is calculated in dependence to the related estimated phase offset to incorporate the predictive character. In particular, the predicted sample phase offsets are calculated as a function of a corresponding predicted phase offset and a measure being indicative of a distance, in the time domain, between a corresponding phase reference point for the predicted phase offset and a phase reference point defined for a specific part of the received signal, preferably for a preceding preamble signal.