VQI(Voice Quality Index) and Drop Call rate improvement in 2G Huawei by Setting more Full Rate and redimension channel

VQI(Voice Quality Index) is Statistic KPI that indicate quality of voice services in GSM network, mostly identical with SQI(Speech Quality Index) in drive test performances. This KPI is also important to improve  and great influences to Drop call rate improvement.Good VQI means good voice quality and thus improving drop call rate performances in our network.There are some method  and step to improve voice quality, The common method is by setting more Full rate(decrease Half Rate services). As we know Full rate is better than Half rate if TRX resources is sufficient(doesn't limited). Half rate usually get more influenced by interference while Full rate is better and good perform as anti interference that's why Full rate services better than Half rate regarding quality improvement of voice services in GSM. Beside setting more full rate, we can also do re-dimension channel by change SDCCH or PDTCH into TCHFR. Please note that we only change for cells with low SDCCH or PDCH Utilization, don't change cells with high SDCCH or PDTCH utilization because will impact to blocking on SDCCH and PDTCH and also Packet Data Access Success Rate(PDASR). I have experiences the method of VQI improvement in 2G Huawei Network in My Country(Indonesia) which is located in Central Java area for Hutchison project. The method is listed as below action:
1. Setting more Full rate--->Increase value of TCHBUSYTHRESHOLD and TCHH AMRPRIORLOAD for cells with low TCH Utilization
2. Channel re-dimension----->Change SDCCH and PDTCH to TCHFR for cells with low SDCCH or PDTCH Utilization

Below are snap shoot Parameter change request(PCR) that we submitted in Netwatcher for your references and guidance about the action:
1. Setting more Full rate
Below picture shows parameter changing of TCHBUSYTHRESHOLD and AMRTCHHPRIORLOAD to get more Full rate Service for VQI Improvement

2. Channel re-dimension
Below picture shows Parameter changing of CHTYPE from SDCCH and PDTCH to TCHFR for VQI Improvement. This CR is only needed to change when SDCCH or PDTCH utilization are low(<<70%)

Those above method can be implemented to improve VQI and Drop Call rate for your GSM Network especially Huawei 2G Network. Below are the result after Parameter implemented in our Network Hutchison Central Java Indonesia.

From the above chart show that VQI was improved after parameter implemented: Increase Full rate allocation and redimensioning channel.
Ok, today sharing is enough for optimization tips about VQI and drop call rate improvement in 2G Huawei Network. hope can help you better in Network optimization knowledge and improve your KPI in your network.Thanks.

You might also Need to know:
- TCH Block Rate Optimization Tips in Huawei GSM
- 2G Voice Quality improvement by TRX Layering Priority
- TBF Drop Improvement tips in Huawei GSM
- GPRS Packet Data Access Rate(PDASR) Improvement in Huawei GSM
- Common question about RF Optimization