Pulse or digital communications – Spread spectrum – Direct sequence
Reexamination Certificate
2004-12-21
2008-10-28
Fan, Chieh M. (Department: 2611)
Pulse or digital communications
Spread spectrum
Direct sequence
C375S316000, C375S147000, C375S229000, C375S232000, C375S233000, C375S234000, C375S235000, C375S236000, C375S343000
Reexamination Certificate
active
07443909
ABSTRACT:
Receiving downlink CDMA signals in a fast-fading environment is facilitated at higher receiver velocities by updating the block-adaptive linear minimum mean square error (LMMSE) downlink CDMA equalizer. The autocorrelation matrix of the observed data is updated by passing block-wise autocorrelation slides through a filter. Each autocorrelation slide is an autocorrelation matrix estimated from a short block of observed data over which the channel can be considered constant. This method achieves a reliable estimate for the autocorrelation matrix when the block size must be small to ensure that the block-wise stationarity assumption holds in cases of fast fading channels. In addition, small block sizes make it possible to satisfy the equalizer delay constraint imposed by hardware and certain voice transmission standards such as CDMA2000 1X where demodulated data must be delivered within only several symbol periods of the signal arrival time.
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Dowling Joe
Guo Yuanbin
McCain Dennis
Nguyen Hoang
Zhang Jianzhong
Fan Chieh M.
Harrington & Smith PC
Lee Siu M
Nokia Corporation
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