Speech coding translation for IP and 3G mobile integrated network

As a novel technique for IP and 3G mobile integrated networks, we propose a speech coding translation scheme that can improve the speech quality of intercommunication among different speech coding standards, such as G.729 of VoIP and AMR of IMT-2000. Through the direct conversion of transmission parameters, this scheme improves speech intelligibility with reduced processing delay compared with conventional schemes, which consist of auxiliary decoding and asynchronous re-encoding. A subjective test by 40 non-experts shows that the proposed scheme significantly improves the subjective speech quality by a probability of 99%. And processing delay in one-way transmission is reduced by 25 ms.