PESQ：
SQI（）
ITU G.107 E模型
STI：Speech Transmission Index, short STI is a measure of speech transmission quality. The absolute measurement of speech intelligibility is a complex science. The STI measures some physical characteristics of a transmission channel (a room, electro-acoustic equipment, telephone line, etc.), and expresses the ability of the channel to carry across the characteristics of a speech signal. STI is a well-established objective measurement predictor of how the characteristics of the transmission channel affects speech intelligibility.
The influence[1] that a transmission channel has on speech intelligibility is dependent on:
- the speech level
- frequency response of the channel
- non-linear distortions
- background noise level
- quality of the sound reproduction equipment
- echos (reflections with delay > 100ms)
- the reverberation time
- psychoacoustic effects (masking effects)
当前测量GSM网络中语音质量的主要方法是使用路测工具并基于PESQ算法进行测量。依据ITU P.862开发的这种客观的测量方法用于评估端到端的语音质量。通常，运营商主要通过基于PESQ算法的纯净语音文件测量网络中的无线信号质量，并对编解码类型相关的干扰以及由于低覆盖率、切换、干扰引起的丢帧对收听质量产生的影响进行量化。另外一种通用的测量方法是基于爱立信提出的语音SQI。该方法可以估算出编解码类型、无线链路参数（如BER、FER以及切换率）等对语音质量产生的影响。