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US 5,249,200 AGranted
Device and method for combining precoding with symbol-rate spectral shaping
AssigneeCodex Corporation
InventorsMichael Chen, M. Vedat Eyuboglu
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Abstract
The device and method provide precoding and symbol-rate transmitter spectral shaping of signals representative of digital information. The invention improves reliability of reception in the presence of non-Gaussian channel noise. The present invention also provides a flexible way of choosing between linear equalization, precoding without spectral shaping, and precoding with spectral shaping.
Claims22
A device for providing symbol-rate transmit spectral shaping of a digital information sequence in a digital transmission system, comprising at least one of:
- modulation means for at least modulating the digital information sequence;
- and
- demodulation means for at least demodulating the modulated digital information sequence to provide an estimate of the digital information sequence;
- wherein:
- the modulation means comprises at least:
- a precoding means operably coupled to receive the digital information sequence, for precoding said sequence utilizing a predetermined monic equivalent channel response h(D) to generate a precoded sequence;
- a symbol-rate spectral shaping means with a monic filter response a(D).noteq.1, operably coupled to the precoding means, for utilizing a spectral shaping filtering function and a first scaling factor to provide a spectrally shaped sequence of precoded symbols;
- and
- a transmission preparation means operably coupled to the symbol-rate spectral shaping means, for generating a spectrally-shaped transmission sequence for transmission on a selected channel;
- and the demodulation means comprises at least:
- an equalizing means operably coupled to receive the spectrally-shaped transmission sequence, for providing an equalized spectrally-shaped sequence of precoded symbols;
- and
- a symbol-rate processing means, operably coupled to the equalizing means, comprising:
- noise prediction means, operably coupled to receive the equalized spectrally-shaped sequence of precoded symbols, for substantially utilizing a symbol-rate noise prediction filter with response b(D)=h(D)/a(D) and at least a second scaling factor to provide a noise prediction filter output;
- and
- decoding means, operably coupled to the symbol-rate noise prediction means, for providing an estimate of the digital information sequence.
13 more elements
A device in a modem for providing symbol-rate transmit spectral shaping of a digital information sequence in a digital transmission system, comprising at least:
- modulation means for at least modulating the digital information sequence;
- and
- demodulation means for at least demodulating the modulated digital information sequence to provide an estimate of the digital information sequence;
- wherein:
- the modulation means comprises at least:
- a precoding means operably coupled to receive the digital information sequence for precoding said sequence utilizing a predetermined monic equivalent channel response h(D) to generate a precoded sequence;
- a symbol-rate spectral shaping means with a monic filter response a(D).noteq.1, operably coupled to and responsive to the precoding means, for utilizing a spectral shaping filtering function and a first scaling factor to provide a spectrally shaped sequence of precoded symbols;
- and
- a transmission preparation means operably coupled to and responsive to the symbol-rate spectral shaping means, for generating a spectrally-shaped transmission sequence for transmission on a selected channel;
- and the demodulation means comprises at least;
- an equalizing means operably coupled to receive the spectrally-shaped transmission sequence, being responsive to the transmission preparation means, for providing an equalized spectrally-shaped sequence of precoded symbols;
- and
- a symbol-rate processing means, operably coupled to and responsive to the equalizing means, comprising:
- noise prediction means, responsive to the equalizing means, being operably coupled to receive the equalized spectrally-shaped sequence of precoded symbols for substantially utilizing a symbol-rate noise prediction filter with response b(D)=h(D)/a(D) and at least a second scaling factor to provide a noise prediction filter output;
- and
- decoding means, operably coupled to and responsive to the symbol-rate noise prediction means, for providing an estimate of the digital information sequence.
13 more elements
A method for providing symbol-rate transmit spectral shaping of a digital information sequence in a digital transmission system, comprising at least one of the sets of steps:
- (A) precoding the digital information sequence utilizing a predetermined monic equivalent channel response h(D) to generate a precoded sequence;
- utilizing a symbol-rate spectral shaping filter with a monic filter response a(D).noteq.1, and a first scaling factor to provide a spectrally shaped sequence of precoded symbols;
- generating a spectrally-shaped sequence for transmission on a selected channel;
- and
- (B) utilizing an equalization unit to provide an equalized spectrally-shaped sequence of said precoded symbols;
- and
- utilizing a symbol-rate noise prediction filter with response b(D)=h(D)/a(D) and at least a second scaling factor to provide a noise prediction filter output, and providing an estimate of the digital information sequence.
4 more elements
Dependencies are inferred from the claim text.