REDUCING THE COMPLEXITY AND STORAGE OF CELP SPEECH CODING USING A SELF-ORTHOGONAL CODEBOOK

An algorithm is proposed to reduce the complexity and memory requireme nt of coded-excited linear prediction (CELP) speech coding. The new al gorithm is based on the concept of designing a special codebook such t hat each codeword is orthogonal to its shifting entries. With this ort hogonal property, the algorithm reduces the codeword searching complex ity of CELP coding significantly. Besides, by rearranging the codeword , only 12.5% of the conventional codebook storage is required. Both se gmental SNR and informal listening showed that the performance of the algorithm is equivalent to that of the original CELP algorithm.