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:
Apr. 15, 1997
Filed:
Dec. 09, 1994
Chris Heegard, Ithaca, NY (US);
General Instrument Corporation of Delaware, Chicago, IL (US);
Abstract
A rotationally invariant trellis coder is provided for encoding data to be transmitted using a two-dimensional symbol modulation. A precoder, provided at the transmitter, processes data such that a counterpart postcoder at the receiver will provide an output that is invariant to any multiple of a 90.degree. rotation. An encoder encodes the precoded data using a transparent binary convolutional code, which can be a punctured or unpunctured code. The encoded data is mapped to a two-dimensional signal space having a plurality of signal points. The signal points are labeled with unique binary codes in which the two least significant bits, denoted by (I.sub.j, Q.sub.j), are permuted and partially complemented to (Q.sub.j, I.sub.j) for each 90.degree. phase rotation around the signal space. The remaining most significant bits for each point, if any, are invariant to such rotation. The postcoder provided at the receiver inverts the precoder and is feedback-free, thus limiting error propagation.