Encoding / decoding method and apparatus of a voice signal using a fixed codebook searching method and an apparatus with him

The fixed codebook of the present invention has been improved to share a fixed codebook of a fixed code book and an enhancement layer of the base layer into a plurality of spaces, to a method and apparatus for encoding or decoding an audio signal using a CELP (Code Excited Linear Prediction) algorithm Layer according as the search by searching for the area other than the spatial distortion is determined by the smallest area in the base layer, it is possible to reduce the bit rate without degrading the performance of the enhancement layer based on the CELP.