System and method for joint coding and decision feedback equalization

Patent 6012161 Issued on January 4, 2000. Estimated Expiration Date:

November 26, 2017. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

Fully adaptive modem receiver using whitening matched filtering
Patent #: 5031195
Issued on: 07/09/1991
Inventor: Chevillat, et al.

Detector for demodulating a received signal and producing an information data signal with reduced intersymbol interference Patent #: 5546430
Issued on: 08/13/1996
Inventor: Liao, et al.

Inventors

Application

No. 979982 filed on 11/26/1997

US Classes:

714/795, Viterbi decoding375/233, Decision feedback equalizer375/341, Maximum likelihood decoder or viterbi decoder714/786Forward error correction by tree code (e.g., convolutional)

Examiners

Primary: Moise, Emmanuel L.

Attorney, Agent or Firm

Oliff & Berridge, PLC

International Classes

G06F 011/10
H03M 013/12

Abstract

The invention relates to joint decision feedback equalization and error correction decoding. To minimize error propagation, the invention uses a combination of enhanced soft decisions and delayed tentative hard decisions from the error correction (Viterbi) decoder to cancel intersymbol interference. Soft decisions are obtained by passing the DFE output through a hyperbolic arc tangent (soft) nonlinear device. These are used to suppress intersymbol interference (ISI) due to multipath with small delays. Tentative hard decisions from a Viterbi decoder are used to cancel ISI due to multipath with large delays, thus remedying the increasing effect of error propagation in channels with large delay spreads. When further combined with antenna diversity and a reduced-complexity DFE concept with adaptive feedforward tap assignment, the invention provides high packet throughput against Rayleigh fading, severe delay spreads, and high Doppler rates.