Pulse or digital communications – Spread spectrum – Direct sequence
Reexamination Certificate
2004-07-19
2009-10-06
Torres, Juan A (Department: 2611)
Pulse or digital communications
Spread spectrum
Direct sequence
C375S232000, C375S229000
Reexamination Certificate
active
07599426
ABSTRACT:
A code division multiple access (CDMA) radio system uses an adaptive filter in a receiver to mitigate multipath radio propagation and to filter out interfering signals. Characteristics of an initial stage of the filter preferably are determined by cross correlation of a generated pilot signal and the input signal with the integration of the correlation performed over a time period selected to be an integral number of symbol periods. The integration causes the portions of the cross correlation corresponding to the user subchannels to average substantially to zero, so that the pilot channel signal correlation is the primary contribution to the signal used to characterize the channel to establish the coefficients of the adaptive filter for the receiver.
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Acorn Technologies, Inc.
Orrick Herrington & Sutcliffe LLP
Torres Juan A
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