Research On Voice Quality MOS Upgrade Strategy In GSM Network

Entering the21st century, the rapid developments in economy andcommunication industry improve people’s living standard, so people’s requirement ofthe network quality also rises. The terminal users’ overall satisfaction declines,communication operators are thus shift focus, customer satisfaction has beenon the list of things to do.For operators, most of the work of GSM network centres on RxQual. RxQual isdivided into of8levels (0-7). In DT test, the value shows the bit error rate (BER) incommunication process. According to the differences in the channel modes, theaccuracies of RxQual given by the terminals are also different, the BER is higher inDTX mode.BER is generated in the wireless transmission. It has close relationship in codemode of communication process. Even with same BER values, different encodingleads to different voice quality. The voice quality of the terminal users is affected byvarious factors but RxQual cannot take everything in account. For example:(1)Different time points leads to the fluctuation in BER. In the premise that average BERvalues are same, the user perception is better when fluctuation is slighter. WhileRxQual is only related to the average BER, so RxQual cannot show the true userperception;(2) Frame-loss greatly affects the voice quality, and RxQual perceptioncannot perceive this phenomenon;(3) Switch causes part of the loss in speech frame,and decreases the voice quality, RxQual will not show this, either.For the problems of the incomplete RxQual, ITU-T proposes a method toperceive the perception of the terminal users-voice quality (MOS). It transmits aspeech reference signal to the terminal. On the the other end of the network, use thedigital signal process (DSP) technology, compare the reference signal and thereceived signals, then MOS is obtained. This method can accurately inmate the voiceperception of the human ears, so it is a true reaction of the voice quality. But Mos isaffected by many factors, the research at home is at an early stage. The Mos value inGSM network of Siping Mobile is in the middle or lower level in province Jilin, theparameters in links are not perfect. In order to improve the Mos, the research of thefactors which affect Mos is necessary.In this paper, the analyzes of the Mos are given, we sort the influence degrees, balance the parameter-setting, get a complete project to improve the voice quality,then use it in the Siping Mobile network. Finally, the whole network struct isimproved, the source allocation is completed, the network function and market serviceare improved, so the customer satisfaction is increased.Through this research, GSM network in Siping Mobile is improved, the networkresource is optimized, the network quality and business income are grown. Itdemonstrates the communication operators’ social responsibility, has a highsocial efficacy.