A study on fast algebraic codebook search method for digital simultaneous voice and data applications

Abstract

This paper proposes a fast algebraic codebook search for digital simultaneous voice and data (DSVD) applications. In this method, the codebook search is simplified by reducing the number of possible position combinations using a mean-based track threshold multiplied by heuristically determined optimum threshold factor. And, an adaptive threshold method is considered for further improvement. Also, to guarantee a complexity requirement of DSVD applications, the maximum number of searching position combinations is limited to 320. The proposed method reduced computational complexity considerably, compared with G.729 with a slight degradation of speech quality. Particularly, it shows better speech quality with lower complexity than G.729A. For the verification of performance improvement, this method is implemented actually in AMR (Adaptive Multi-Rate) vocoder which is mandatory speech codec in W-CDMA multimedia terminal (3G-324M terminal).