Pulse or digital communications – Synchronizers – Phase displacement – slip or jitter correction
Reexamination Certificate
2007-04-10
2007-04-10
Patel, Jay K. (Department: 2611)
Pulse or digital communications
Synchronizers
Phase displacement, slip or jitter correction
C375S374000, C375S375000
Reexamination Certificate
active
10413700
ABSTRACT:
Techniques are provided for tracking residual frequency error and phase noise in an OFDM system. At a receiver, each received OFDM symbol is transformed with an FFT to obtain received modulation symbols, which are serialized. A phase locked loop (PLL) operates on the serialized received modulation symbols and provides an independent phase correction value for each received modulation symbol. Each received modulation symbol is corrected with its own phase correction value to obtain a phase-corrected symbol. The phase error in each phase-corrected symbol is detected to obtain a phase error estimate for that phase-corrected symbol. The phase error estimate for each phase-corrected symbol is filtered (e.g., with a second-order loop filter) to obtain a frequency error estimate, which is accumulated to obtain a phase correction value for another received modulation symbol. The phase-corrected symbols are not correlated because independent phase correction values are used for the received modulation symbols.
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Ghulamali Qutub
Minhas Sandip S.
Patel Jay K.
Qualcomm Incorporated
Rouse Thomas R.
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