Abstract
Performance of speaker recognition degrades while speech is coded by a speech coder. In this thesis, we evaluate the performance of G.729A and GSM coded speech, and the residue signal and prosodic features are used to improve the performance. The residue signal is shown to be very useful for speaker recognition, and the prosodic features are shown to be very robust to codec distortion. Moreover, an improved prosodic model is proposed in this thesis and the performance is better than that of the previously proposed model in both speaker identification and speaker verification.