US 11,784,709 B2
Method and receiver device for detecting the start of a frame of a satellite communications signal
Lyonel Barthe, Toulouse (FR); and Benjamin Gadat, Toulouse (FR)
Assigned to AIRBUS DEFENCE AND SPACE SAS, Toulouse (FR)
Appl. No. 17/919,187
Filed by AIRBUS DEFENCE AND SPACE SAS, Toulouse (FR)
PCT Filed Apr. 15, 2021, PCT No. PCT/FR2021/050659
§ 371(c)(1), (2) Date Oct. 14, 2022,
PCT Pub. No. WO2021/209719, PCT Pub. Date Oct. 21, 2021.
Claims priority of application No. 2003838 (FR), filed on Apr. 16, 2020.
Prior Publication US 2023/0120948 A1, Apr. 20, 2023
Int. Cl. H04B 7/185 (2006.01)
CPC H04B 7/18513 (2013.01) 20 Claims
OG exemplary drawing
 
1. A method for detecting a start of a frame of a communication signal, said frame including a preamble corresponding to a predetermined sequence of binary symbols, said method including:
sampling of the signal,
shape filtering of samples obtained directly at an output of the sampling,
a first phase for estimating an approximate frequency error of the signal and a candidate first sample for the start of the frame, said first phase including:
for each of a plurality of predetermined frequency hypotheses:
calculating a correlation between the samples obtained after the shape filtering and at least one portion of the preamble, and
estimating on the one hand a candidate first sample for the start of the frame corresponding to one of the samples for which a best correlation value is obtained among the predetermined frequency hypothesis which is higher than a predetermined threshold and, on the other hand, of an approximate frequency error from the predetermined frequency hypotheses having provided the best correlation value,
buffering of the samples obtained at the output of the sampling or at the output of the shape filtering in a buffer memory while the first phase is executed,
a second phase for accurately estimating a final candidate sample for the start of the frame, said second phase including:
applying a frequency correction to the samples obtained at the output of the buffer memory, said frequency correction being determined from the approximate frequency error estimated at the first phase,
performing a correlation between the corrected samples and the preamble for a limited set of samples comprising the candidate first sample,
determining the final candidate sample for the start of the frame as the sample for which the best correlation value is obtained.