US 2006/0233153 A1 · Method and apparatus for automatic frequency correction

Abstract

A technique is provided for automatic frequency offset correction in a wireless communication system. After demodulating and decoding a received signal in a receiver, channel estimation is also performed. The technique further includes re-encoding and re-modulating the decoded and demodulated signal with a coding and modulation scheme different from the received signal. The signal is reconstructed signal on the basis of the re-encoded and re-modulated signal and estimated channel characteristics. A frequency error is estimated based on the reconstructed signal and the original received signal. A threshold for a comparator is determined on the basis of the estimated offset amount determined by the comparison threshold and the estimated frequency offset.

Claims9

Dependent claims

An automatic frequency correction device in a wireless receiver, the wireless receiver demodulating and decoding an original received signal and delivering the demodulated and decoded signal and an estimated channel to the device, the device comprising:

a re-coding and re-modulation unit that encodes and modulates the demodulated and decoded signal into a re-coded and re-modulated signal using a scheme different from the received signal;
a reconstruction unit connected to the re-coding and re-modulation unit, and which receives the estimated channel and the re-coded and re-modulated signal to generate a reconstructed signal;
a frequency offset estimation unit connected to the reconstruction unit for calculating an offset amount using the reconstructed signal and the original received signal;
a comparator that receives the estimated channel to determine a threshold;
and
an offset estimate adjustment unit connected to the output of the comparator and the frequency offset estimation unit, wherein the offset estimate adjustment unit adjusts the frequency offset based upon the comparator output and the offset amount.

3 more elements

A receiver in the wireless communication system comprising:

an antenna for receiving an original received signal;
a filter unit connected to the antenna for signal noise and interference filtering;
an A/D converter connected to the filter unit;
a demodulation and decoding unit connected to the A/D converter for signal decoding and demodulation;
a channel estimation unit connected to the A/D converter for generating an estimated channel;
an automatic frequency correction device comprising:
(a) a re-coding and re-modulation unit that encodes and modulates the demodulated and decoded signal into a re-coded and re-modulated signal using a scheme different from the received signal;
(b) a reconstruction unit connected to the re-coding and re-modulation unit, and which receives the estimated channel and the re-coded and re-modulated signal to generate a reconstructed signal;
(c) a frequency offset estimation unit connected to the reconstruction unit for calculating an offset amount using the reconstructed signal and the original received signal;
(d) a comparator that receives the estimated channel to determine a threshold;
and
(e) an offset estimate adjustment unit connected to the output of the comparator and the frequency offset estimation unit, wherein the offset estimate adjustment unit adjusts the frequency offset based upon the comparator output and the offset amount.

9 more elements

Dependencies are inferred from the claim text.

Method and apparatus for automatic frequency correction

Life of this patent

Method and apparatus for automatic frequency correction

Life of this patent

Abstract

Claims9