A search complexity improvement of vector quantization to immittance spectral frequency coefficients in AMR-WB speech codec

Bing Jhih Yao, Cheng Yu Yeh*, Shaw-Hwa Hwang

*Corresponding author for this work

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

An adaptive multi-rate wideband (AMR-WB) code is a speech codec developed on the basis of an algebraic code-excited linear-prediction (ACELP) coding technique, and has a double advantage of low bit rates and high speech quality. This coding technique is widely used in modern mobile communication systems for a high speech quality in handheld devices. However, a major disadvantage is that a vector quantization (VQ) of immittance spectral frequency (ISF) coefficients occupies a significant computational load in the AMR-WB encoder. Hence, this paper presents a triangular inequality elimination (TIE) algorithm combined with a dynamic mechanism and an intersection mechanism, abbreviated as the DI-TIE algorithm, to remarkably improve the complexity of ISF coefficient quantization in the AMR-WB speech codec. Both mechanisms are designed in a way that recursively enhances the performance of the TIE algorithm. At the end of this work, this proposal is experimentally validated as a superior search algorithm relative to a conventional TIE, a multiple TIE (MTIE), and an equal-average equal-variance equal-norm nearest neighbor search (EEENNS) approach. With a full search algorithm as a benchmark for search load comparison, this work provides a search load reduction above 77%, a figure far beyond 36% in the TIE, 49% in the MTIE, and 68% in the EEENNS approach.

Original languageEnglish
Article number104
JournalSymmetry
Volume8
Issue number10
DOIs
StatePublished - 1 Jan 2016

Keywords

  • Immittance spectral frequency (ISF)
  • Speech codec
  • Triangular inequality elimination (TIE)
  • Vector quantization (VQ)
  • VoIP

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