Multiplex communications – Generalized orthogonal or special mathematical techniques – Quadrature carriers
Reexamination Certificate
2007-01-09
2007-01-09
Hsu, Alpus H. (Department: 2616)
Multiplex communications
Generalized orthogonal or special mathematical techniques
Quadrature carriers
C370S210000, C375S232000, C375S260000, C375S349000, C375S350000, C455S060000
Reexamination Certificate
active
10217117
ABSTRACT:
A method and apparatus for estimating channel characteristics in a multicarrier wireless receiver such as an OFDM wireless receiver. The method includes determining a channel estimate for each of a set of subcarriers by receiving multicarrier data as a result of a wireless transmission of data that includes a known signal, wherein the determining uses a part of the received data that corresponds to the known signal. The method further includes smoothing the channel estimates according to a smoothing filter to form smoothed channel estimates. The smoothed channel estimate for a particular subcarrier includes a contribution from the channel estimates of the particular subcarrier's one or more immediate neighbors to take advantage of correlation that may exist between the particular subcarrier's channel and the channels of that subcarrier's one or more immediate neighbors. In one version, the transmitted data includes at least one additional known signal, and each smoothed channel estimate is a smoothed version of the average of sets of channel estimates. In such a version, each set of channel estimates is determined using a respective part of the received data that corresponds to a corresponding one of the known signals.
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Hart Brian
O'Sullivan John D
Cisco Systems Wireless Networking (Australia) Pty Limited
Dov Rosenfeld Inventek
Hsu Alpus H.
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