Method and apparatus for fine frequency synchronization in multi-carrier demodulation systems

US7061997B1 · kind B1 · utility

Assignee

• Fraunhofer-Gesellschaft zur förderung der angewandten Forschung e.V. · DE

Inventors

• Ernst Eberlein · Erlangen, DE
• Sabah Badri · Erlangen, DE
• Stefan Lipp · Bad Liebenzell, DE
• Stephan Buchholz · Munich, DE
• Albert Heuberger · Erlangen, DE
• Heinz Gerhaeuser · Erlangen, DE

Key dates

• Filing date: Apr 14, 1998
• Grant date: Jun 13, 2006
• Expiry date: Apr 14, 2018

Classification

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

Abstract

A method and an apparatus relating to a fine frequency synchronization compensating for a carrier frequency deviation from an oscillator frequency in a multi-carrier demodulation system of the type capable of carrying out a differential phase decoding of multi-carrier modulated signals, the signals comprising a plurality of symbols, each symbol being defined by phase differences between simultaneous carriers having different frequencies. A phase difference between phases of the same carrier in different symbols is determined. Thereafter, a frequency offset is determined by eliminating phase shift uncertainties related to the transmitted information from the phase difference making use of a M-PSK decision device. Finally, a feedback correction of the carrier frequency deviation is performed based on the determined frequency offset. Alternatively, an averaged frequency offset can be determined by averaging determined frequency offsets of a plurality of carriers. Then, the feedback correction of the frequency deviation is performed based on the averaged frequency offset.