Robust and efficient quantization of speech LSP parameters using structured vector quantizers

Three robust algorithms based on the recently proposed concept of structured vector quantization have been developed for quantization of speech LSP (line spectrum pair) parameters. The first algorithm exploits interframe correlation of the LSP parameters and requires 24 bits per LSP vector to achieve 1 dB average spectral distortion. The second and third algorithms quantize each LSP vector independently and for 1 dB distortion require 29 and 25 bits per vector, respectively. The last two algorithms result in a considerably smaller fraction of frames with distortions greater than 2 dB as compared to other schemes proposed so far