Pulse or digital communications – Systems using alternating or pulsating current – Plural channels for transmission of a single pulse train
Reexamination Certificate
2007-09-11
2010-11-30
Liu, Shuwang (Department: 2611)
Pulse or digital communications
Systems using alternating or pulsating current
Plural channels for transmission of a single pulse train
C375S267000, C375S295000, C375S343000, C370S203000, C370S204000, C370S205000, C370S206000, C370S207000, C370S208000, C370S209000, C370S210000
Reexamination Certificate
active
07844006
ABSTRACT:
Described is a method for compensation of an OFDM signal propagating through Doppler-distorted, time-varying multipath channels. The method is based on low-complexity post-FFT signal processing. Minimum mean square error combining of signals is performed for signals received at spatially-distributed receiver elements using adaptive channel estimation and phase tracking. Doppler shifts are modeled as a consequence of motion-induced time compression and dilation. The Doppler rate is assumed constant over one OFDM block but can vary between OFDM blocks. Thus a non-constant Doppler shift is accommodated by the method. Non-uniform Doppler compensation across subchannels is based on adaptive estimation and prediction of the Doppler rate. A single adaptively estimated parameter is used to track the phases of all the carriers and channel estimates are updated on a block by block basis.
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Guerin William G.
Guerin & Rodriguez LLP
Liu Shuwang
Massachusetts Institute of Technology
Patel Dhaval
LandOfFree
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