Research And Implement Of Voice Quality Evaluation Function Based On Softswitch Test System

With Softswitch being a hotspot of the communications industry and gradually getting mature, next generation network (NGN) based on Softswitch technology can take most of the service by now which used to be carried by traditional PSTN Network . However, during this period, a large amount of problems have emerged. For example, Qos issue is one of the most urgent problems faced by Telecommunications Operator that should be solved as fast as possible. Furthermore, voice quality problem has the top priority in this type of problems. Because of the essential difference between two types of network that the voice is carried by IP mode in Softswitch network while by circuit switching mode in PSTN network, so we must strengthen the management and monitoring of voice quality. According to the current status of Softswitch network, with making deep analysis the related signaling and doing much research on speech coding and evaluation algorithms in this thesis, finally we design an appropriate solution for the voice quality test of Softswitch mobile network based PESQ algorithm. Through it, we can get the detail index of the network quality and the quality differ caused by different factors and then by these way the system can help to improve the voice qualityThe main body of the thesis involves detailed research and implementation on following aspects:1) Analyse the overall structure of softswitch test system which focuses on implementation and research on evaluation of softswitch voice quality;2) Route loop-back mode is chosen to achieve the deployment of the entire network without the management of the whole network;3) Use background admin mechanism to achieve user management functional, operational status query function and customized task management function;4) Distinguish normal or abnormal call link status with special DTMF codes which are sent and received by the test system itself and catch the network monitoring indexes;5) Customize voice standards and analyse the entire send-receive implementation process so as to generate call logs;6) The final step of voice quality-evaluation, MOS value is scored by the amended and improved PESQ algorithm of which is then the compiling and accuracy will be validated. The background management will also show the performance analysis and statistical comparison.