Patent ID: 6678334
Filing Date: 2004-01-13
Classification: H03M,H04L

Abstract:
A method of reducing constellation complexity of a trellis-based scalar-vector quantizer for a memoryless data source in a communication system, comprising the steps of:defining an unbounded set of reproduction symbols in which neighboring symbols are distanced from each other by a predetermined factor; grouping the set of said reproduction symbols into a region; assigning a norm value to the region and determining a threshold norm value for the region; bounding the region to an element in the region wherein the element is the largest element in the region with respect to the norm of the region; and determining a parameter for the region as a function of the norm of the region which minimizes shape distortion of the region, thereby reducing the complexity of the trellis-based scalar-vector quanitizer for the source and optimally shaping the constellation, wherein the memoryless source is a Gaussian source and the unbounded set of reproduction symbols is denoted as Q and is defined as: Q={+/âˆ’(2iâˆ’1)&bgr;: i=1, 2, . . . }, wherein,&bgr; is a factor that minimizes distortion and is determined by plotting quantizer distortion on encoding zero-mean unit-variance source sequence as a function of &bgr;, and i is a region index.