The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 29, 2008
Filed:
Jan. 05, 2004
Georg Frank, Nuremberg, DE;
Mathias Pauli, Nuremberg, DE;
Udo Wachsmann, Schwabach, DE;
Peter Schramm, Eching, DE;
Georg Frank, Nuremberg, DE;
Mathias Pauli, Nuremberg, DE;
Udo Wachsmann, Schwabach, DE;
Peter Schramm, Eching, DE;
Telefonaktiebolaget LM Ericsson (publ), Stockholm, SE;
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.