Pulse or digital communications – Spread spectrum – Direct sequence
Reexamination Certificate
2007-05-29
2007-05-29
Payne, David C. (Department: 2611)
Pulse or digital communications
Spread spectrum
Direct sequence
C375S142000
Reexamination Certificate
active
10423739
ABSTRACT:
A method and apparatus for multi-path channel characterization in a Direct Sequence Spread Spectrum based wireless communication system is provided. The multipath channel is modeled as a tapped delay line FIR filter with L taps corresponding to L paths. A pre-defined training sequence is transmitted over the multipath channel. The received signal is sampled and cross correlations are computed between the samples obtained and the spreading sequence for various time lags to obtain the symbol boundary. Thereafter, a desired set of L cross correlations for L time lags around the symbol boundary is estimated. For this, all the L possible sets of L cross correlations for L time lags around the symbol boundary are considered. The energy in the cross correlations corresponding to each considered set is calculated. The set of L cross correlations having the maximum energy is selected for tap computation. The tap coefficients are estimated by solving a set of L simultaneous linear equations.
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Barman Kaushik
Reddy Vellenki Umapathi
Botjer William L.
Ettehadieh Aslan
Hellosoft Inc.
Payne David C.
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