Bandwidth extension of G.729 speech coder using search-free codebook mapping

A search-free codebook mapping algorithm for bandwidth extension in G.729 compressed domain is introduced in this paper. We design a wideband line spectrum pair (LSP) codebook which is coupled with the same index as the LSP codebook of the G.729 speech codec. The received narrowband LSP codebook indices are used to directly induce wideband LSP codewords. Thus, the proposed scheme eliminates codebook search processing to estimate the wideband spectrum envelope. Its performance was assessed via the perceptual evaluation of speech quality (PESQ), spectral distortion (SD), informal listening tests, and weighted million operations per second (WMOPS) calculations.