The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 14, 1995
Filed:
Oct. 29, 1993
Sandeep Chennakeshu, Cary, NC (US);
Paul W Dent, Cary, NC (US);
Ravinder D Koilpillai, Cary, NC (US);
Raymond L Toy, Cary, NC (US);
General Electric Company, Schenectady, NY (US);
Abstract
A low complexity adaptive equalizer for use in U.S. digital cellular radios demodulates .pi./4-shifted differentially encoded quadrature phase shift keyed (DQPSK) encoding in the presence of intersymbol interference (ISI) with reduced decoding complexity by employing an estimated received constellation which takes into account channel changes over time and ISI. The decoding complexity is reduced by tracking a reduced number of estimated reference constellation points and taking advantage of the geometry to estimate the remaining symbol constellation points. A slot of symbols is decoded, employing unique filtering, in segments from the beginning in a forward direction and from the end in a reverse direction meeting at a fade point. This isolates a fade and allows the equalizer to perform more reliably.