Speech compression using CELP speech coding technique in GSM AMR

Abstract

In cellular communication technology, quality of voice output at destination depends on the channel condition. Bad channel condition will produce many errors in the voice output and hence the voice quality. To maintain the voice quality in various channel condition AMR is used. Various modes of bit rate is used in AMR, from low to high bit rate is used depend on the channel condition. Low bit rate modes is used in a bad channel condition to allow more bits for channel coding, while high bit rate on the contrary. Recently various speech (source) coding techniques, such as: CELP, ACELP, RPE-LTP, are used in different applications. In this study the application of CELP in AMR is observed. MATLAB program simulation is used to observe and calculate errors occur in the system. The difference of resulted error produced in AMR using CELP is not significant. From low bit rate (5.9 kbps) to high bit rate (12.2 kbps), the error difference is less than 1%.