Patent ID: 7388902
Filing Date: 2008-06-17
Classification: H04B,H04J,H04L

Abstract:
1. A system, comprising: a baseband signal generator capable of generating a baseband signal from a received signal, the received signal comprising a preamble comprising a portion of known symbols spread in frequency by a pseudo-random sequence of chips and a portion of information symbols spread in frequency by the pseudo-random sequence of chips, and the baseband signal further comprising a modulation related to a shift in frequency from a transmitted frequency of the received signal; a correlator capable of generating a correlation signal based on a correlation between the portion of information symbols of the baseband signal and the pseudo-random sequence, the correlation signal comprising at least one or more correlation components based on at least one of an in-phase component of the baseband signal and a quadrature component of the baseband signal; a DOT-signal generator capable of generating a DOT signal based on a sum of two direct products of successive samples of the correlation components; a CROSS-signal generator capable of generating a CROSS signal based on a difference between two crossed products of successive samples of the correlation components; a modulation estimator capable of generating an estimated signal based on a period of the modulation of the baseband signal related to the shift in frequency based on an inverse of an arctangent of a ratio between the CROSS signal and the DOT signal at at least one symbol period multiplied by π/2 times a number of chips in the at least one symbol period; and a frequency-shift corrector capable of correcting the modulation of the baseband signal related to the shift in frequency by correcting one of the baseband signal and the correlation signal based on the estimated signal.