Vo IP 的语音质量分析与控制

分析了VoIP语音质量的影响因素，通过E模型定量地描述了语音质量与端到端延迟和丢包率的关系。为了控制VoIP的语音质量，计算出VolP系统在各种情况下的语音质量极限，提出一种自适应编码和分组封装的控制策略。将该方法应用于自行开发的IP电话网关，实际测试证明能在很大程度上提高VoIP的语音质量。

Analysis and control of speech quality in VoIP

Factors affecting the speech quality of VoIP system are analyzed. A mathematic relation between speech quality and end-to-end delay and/or rate of packet loss is presented based on E-model. To control the speech quality of VoIP, the limit of speech quality is calculated in all cases and some self-adaptive encode and package methods are suggested. These methods are applied to IP telephony gateway and the results of testing show that these adaptive mechanisms can improve the speech quality of VoIP greatly.