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US 2006/0133459 A1Published application
Method for receiving spectrum spreading signals with frequency shift correction
AssigneeXantima LLC
InventorsChristophe Boulanger, Laurent Ouvry, Bernard Piaget, Didier Lattard
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Abstract
Method for receiving spectrum spreading signals with frequency shift correction. According to the invention, the modulation period related to the Doppler effect is estimated by using a preamble and a correction signal is elaborated, the signal transmitting the information is then corrected by this correction signal. Base band digital signals are operated upon by using the DOT and CROSS components. Application to digital transmissions.
Claims10
An apparatus, comprising:
- means for receiving a signal, the signal comprising a preamble comprising a sequence of known symbols spread in frequency by a pseudo-random sequence, followed by a sequence of information symbols spread in frequency by the pseudo-random sequence;
- means for forming a base band signal based at least in part on the received signal;
- means for performing a correlation between the base band signal and the pseudo-random sequence at least in a portion of the signal corresponding to information symbols in order to obtain a correlation signal;
- means for demodulating the correlation signal to obtain a demodulation signal,
- means for restoring the information symbols;
- and
- means for correcting a frequency shift in the received signal, said means for correcting a frequency shift comprising:
- means for processing a portion of the correlation signal corresponding to a preamble of the correlation signal, said processing means being capable of estimating a modulation period affecting the correlation signal resulting from the frequency shift and a correcting signal;
- and
- means for correcting the correlation signal in a portion of the correlation signal corresponding to the information symbols, said correcting means being capable of correcting the correlation signal via the correcting signal.
7 more elements
An apparatus, comprising:
- first correlation circuit capable of generating a first correlation signal based at least in part on a received in phase signal;
- a second correlation circuit capable of generating a second correlation signal based at least in part on a received in quadrature signal;
- a differential demodulator capable of generating a DOT signal or a CROSS signal, or combinations thereof, based at least in part on the first and second correlation signals;
- an estimation circuit capable of estimating a Doppler effect on said DOT signal or said CROSS signal, or combinations thereof;
- and
- a correction circuit capable of correcting the Doppler effect on at least one of said DOT signal or said CROSS signal, or combinations thereof.
3 more elements
Dependencies are inferred from the claim text.