Multiplex communications – Generalized orthogonal or special mathematical techniques – Particular set of orthogonal functions
Reexamination Certificate
2006-08-29
2006-08-29
Phunkulh, Bob A. (Department: 2616)
Multiplex communications
Generalized orthogonal or special mathematical techniques
Particular set of orthogonal functions
C370S210000, C375S340000
Reexamination Certificate
active
07099270
ABSTRACT:
A multi-path equalization system for orthogonal frequency division multiplexing communication (OFDM) system includes a first estimator for estimating the channel characteristic using pilot signal. A divider is coupled to the estimator for dividing each sub-carrier with the channel characteristic to get the equalization to the data signal. A de-mapper uses the phase and amplitude correction of the channel estimate to recover the data signals. An improved channel estimation is provided by a repeat channel estimation feedback loop that includes the de-mapper a multiplier, an inverse fast Fourier transform (IFFT), a low pass filter and a fast Fourier transform (FFT). The improved channel estimation is obtained by multiplying at the multiplier the conjugate of the de-mapped data to the input sub-carriers and applying inverse FFT, low pass filtering and FFT to get the new channel estimate. Each sub-carrier is divided with new channel characteristic to get new equalization to the data signal. The channel estimation is repeated until there is convergence. The output is provided after the de-mapper. In the case of channel decoding to improve performance a Viterbi decoder and convolutional encoder is coupled in loop between the de-mapper and the multiplier.
REFERENCES:
patent: 6940914 (2005-09-01), Lo et al.
patent: 6990153 (2006-01-01), Farhang-Boroujeni et al.
patent: 7023928 (2006-04-01), Laroia et al.
patent: 2001/0015954 (2001-08-01), Kuwabara et al.
patent: 2002/0145971 (2002-10-01), Cho et al.
patent: 2002/0181549 (2002-12-01), Linnartz et al.
patent: 2003/0128656 (2003-07-01), Scarpa
patent: 0 954 143 (1999-11-01), None
patent: 1 209 836 (2002-05-01), None
“A Novel Channel Estimation Method for OFDM Mobile Communication Systems Based on Pilot Signals and Transform-Domain Processing”, Yuping Zhao and Aiping Huang, VTC 1997, pp. 2089-2093.
“DSP-Based OFDM Demodulator and Equalizer for Professional DVB-T Receivers”, Fabrizio Frescura, et al., IEEE Trans. Broadcasting, vol. 45, No. 3, Sep. 1999, pp. 323-332.
“Digital Broadcasting for Television, Sound, and Data Services; Framing Structure Channel Coding and Modulation for Digital Terrestrial Television”, ETS 300 744, Mar. 1997, pp. 1-48.
Brady III Wade James
Neerings Ronald O.
Phunkulh Bob A.
Telecky , Jr. Frederick J.
Texas Instruments Incorporated
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