Sync detection and frequency recovery for satellite systems
AssigneeThomson Licensing
InventorsPaul Gothard Knutson, Dirk Schmitt, Wen Gao
Life of this patent
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Abstract
A method of frame sync detection is described. A first and second differential correlation of a data stream is calculated, at a plurality of delay and conjugate multipliers. The first and second differential correlations are convolved with a previous set of differential correlations. A correlation peak is calculated, at a sync detector, using the convolved differential correlations, to detect a frame sync.
Claims25
A method of frame sync detection, comprising:
- calculating a first and second differential correlation of a data signal, at a plurality of delay and conjugate multipliers;
- convolving the first and second differential correlations with a previous set of differential correlations;
- and
- calculating a correlation peak, at a sync detector, using the convolved differential correlations, to detect a frame sync.
An apparatus for frame sync detection, comprising:
- delay and conjugate multipliers, that calculate a first differential correlation and a second differential correlation of a data stream and convolves the first and second differential correlations with a previous set of differential correlations;
- and
- a sync detector, that calculates a correlation peak using the convolved differential correlations, to detect a frame sync.
A method of data aided frequency estimation, comprising:
- receiving a plurality of frames, at a storage field, including a plurality of sync signals having the same sync pattern in each frame transmitted at known intervals;
- calculating a frequency estimate of the plurality of frames, at a sum function block and an arg function block.
An apparatus for data aided frequency estimation, comprising:
- a storage field, that receives a plurality of frames including a plurality of sync signals having the same sync pattern in each frame transmitted at known intervals;
- a sum function block and an arg function block, that calculates a frequency estimate of the plurality of frames.
A method of non data aided maximum likelihood frequency estimation, comprising
- receiving a plurality of frames, at a storage field, including a plurality of sync signals;
- computing a maximum likelihood, at an Mth power block, on the plurality of frames;
- performing an autocorrelation function, at an autocorrelation block, to exchange a phase step increment measurement with the Mth power block;
- performing a differential correlation, at a sum function block and an arg function block.
An apparatus for non data aided maximum likelihood frequency estimation, comprising
- a storage field, that receives a plurality of frames, including a plurality of sync signals;
- an Mth power block, that computes a maximum likelihood of the plurality of frames;
- an autocorrelation block, that performs an autocorrelation function to exchange a phase step increment measurement with the Mth power block;
- a sum function block and an arg function block, that performs a differential correlation.
A method of frequency estimation correction performed by a feedback frequency recovery loop circuit, comprising
- performing a derotation on the sync symbols and data symbols within a received data signal;
- processing the data signal, at a matched filter;
- performing frequency estimation, at a frequency estimator, based on the processed data signal received from the matched filter;
- smoothing the frequency estimates, at a loop filter;
- feeding the output signal back to a derotator, at a numerically controlled oscillator.
A feedback frequency recovery loop circuit for frequency estimation correction, comprising
- A derotator, that derotates sync symbols and data symbols within a received data signal;
- a matched filter, that processes the data signal;
- a frequency estimator, that performs frequency estimation, based on the processed data signal received from the matched filter;
- a loop filter, that smoothes the frequency estimates;
- a numerically controlled oscillator, that feeds the output back to the derotator.
A method of frequency estimation correction in a feedforward frequency recovery loop circuit, comprising
- resampling a data signal, at a symbol timing recovery block, to enable timing recovery of sync symbols and data symbols;
- processing the data signal, at a matched filter;
- performing frequency estimation, at a frequency estimator, based on the processed data signal received from the matched filter;
- feeding the output signal to a derotator, at a numerically controlled oscillator.
An apparatus for frequency estimation correction in a feedforward frequency recovery loop circuit, comprising
- a symbol timing recovery block, that resamples the data signal to enable timing recovery of sync symbols and data symbols;
- a matched filter, that processes the data signal;
- a frequency estimator, that performs frequency estimation based on the processed data signal received from the matched filter;
- a numerically controlled oscillator, that feeds the output to a derotator.
Dependencies are inferred from the claim text.