VoIP Gateway-Speech Coding And Decoding Technology Research And Implementation

As technologies in VoIP evolved rapidly, a varity of its application have come into life. The gateway of VoIP, as discussed in this paper, acted as an important device in voice communication.The selection and implementation of the speech compressing algorithm is considered as the key which balance the price and voice quality. As a result, to design a good performance, price reasonable speech compressing module becomes more and more important.In 1996, speech coding at 8kbit/s using CS-ACELP was standardized as Recommendation G.729. Comparing with the other speech compressing algorithms, G.729 can do a better job on solving the conflict between the chip velocity and the speech quality. Therefore, G.729 has been used widely in multi-media communication, cellular mobile communication system, IP network telephone.Based on all the above, this design focuses on the principle of G.729, write the codes using C language, come out with the design on both hardware and software of the VoIP gateway, give the result of the test and the performance compare with the TI TMS320LC549.According to the test result, this design realized the G.729 algorithm well. The performance is better than the TMS320LC549's. Because the optimal mix of price and performance against the other kin chips, the speech compressing module handled by the LSI403LP will be used widely in various voice communication systems. I believe that the VoIP gateway based on LSI403LP will have a perfect market.