Methods of reducing the complexity of trellis-based scalar-vector quantizers

• US 6,678,334 B1
• Filed: 12/14/1999
• Issued: 01/13/2004
• Est. Priority Date: 12/14/1999
• Status: Expired due to Fees

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Lee, Cheng-Chieh
• Primary Examiner(s): Tse, Young T.
• Assistant Examiner(s): Lugo, David B.
• Application Number:
  US09/460,468
• Time in Patent Office: 1,491 Days
• Field of Search: 375/261, 375/265, 375/285, 375/296, 375/298, 375/240.03, 375/243, 375/245, 375/286, 714/792
• US Class Current: 375/265
• CPC Class Codes: H03M 7/3082 Vector coding for television signals, see H04N19/94
• CPC Class Codes: H04L 25/03828 Arrangements for spectral shaping; Arrangements for providing signals with specified spectral properties partial response systems H04L25/497
• CPC Class Codes: H04L 27/3427 in which the constellation is the n - fold Cartesian product of a single underlying two-dimensional constellation

Abstract

Methods of a reducing the complexity of Trellis-Based Scalar-Vector Quantizer (TB-SVQ) includes the initial step of defining an unbounded set of reproduction symbols in which neighboring symbols are distanced from each other by a predetermined factor. The set of the representation symbols is grouped into a region and a norm value is assigned to the region. A threshold value for the norm is then determined and the region is bound to an element in the region with respect to the norm of the region. A region parameter is then determined as a function of the norm of the region to minimize the shape gain of the region and to thereby reduce the complexity of the TB-SVQ for the source and optimally shape a constellation associated with the region. The inventive methods achieve a shaping gain of substantially 1.53 dB which is the theoretical limit of shaping gain. Thus, these methods optimally shape the constellation and achieve highly efficient data transmission.

Claims

1. 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;

2. The method of claim 1, wherein the reproduction symbols of the set are grouped as follows:

3. The method of claim 2, wherein the quantization rate is 2 bits/sample.

4. The method of claim 2, wherein the quantization rate is 3 bits/sample.

5. The method of claim 4, wherein the constellation is shaped at a shaping gain of about 1.53 dB.