Trellis encoding technique for PCM modems

• US 6,301,683 B1
• Filed: 06/09/1998
• Issued: 10/09/2001
• Est. Priority Date: 06/09/1997
• Status: Expired due to Fees

• Current Assignee: VOCAL Technologies Ltd.
• Original Assignee: VOCAL Technologies Ltd.
• Inventors: Hirzel, Frederic J.
• Primary Examiner(s): DeCady, Albert
• Assistant Examiner(s): LAMARRE, GUY J
• Application Number:
  US09/093,704
• Time in Patent Office: 1,218 Days
• Field of Search: 714/792, 714/755, 714/786, 714/783, 714/800, 375/222, 375/265, 375/216, 375/262, 375/298, 375/296, 375/341, 375/130, 375/332, 375/285, 375/295, 375/342, 455/43
• US Class Current: 714/792
• CPC Class Codes: H03M 13/235 Encoding of convolutional codes, e.g. methods or arrangements for parallel or block-wise encoding
• CPC Class Codes: H03M 13/256 with trellis coding, e.g. with convolutional codes and TCM

Abstract

A method of applying a multidimensional error reduction/correction algorithm on a stream of one dimensional symbols, by converting the stream of one dimensional symbols into a corresponding stream of two dimensional symbols; and, applying the multidimensional error reduction/correction algorithm to the stream of two dimensional symbols. The inventions provides a method of normalizing a metric used by an error reduction/correction algorithm on a stream of symbols wherein the symbols are non-uniformly spaced, by: determining a minimum distance (dmin) between two closest symbols in the stream, for each symbol in the stream, determining a minimum distance (dsym) between the each symbol in the stream and each of its adjacent neighboring symbols, and, normalizing the metric used by the error reduction/correction algorithm by the ratio dmin/dsym.

Claims

1. A method of normalizing a receiver metric used by an error reduction/correction algorithm on a stream of symbols wherein said symbols are non-uniformly spaced, comprising:

determining a minimum distance (dmin) between two closest symbols in said stream;

for each symbol in said stream, determining a minimum distance (dsym) between said each symbol in said stream and each of its adjacent neighboring symbols; and

normalizing said receiver metric used by said error reduction/correction algorithm by the ratio dmin/dsym.

2. The method recited in claim 1 wherein said error reduction/correction algorithm is a trellis decoder.