It depends upon lots of factors to achieve the best Quality of Service for Voice in LTE.
Quality of Service will be dependent on these factors i have mentioned below:
- Bit rate, delay, jitter, packet loss rate (PLR)
- Power consumption
- Call setup delay, Call setup success rate
- Failed calls, dropped calls, retransmission
- MOS (Mean Opinion Score)
- Network Characteristics (Lossy link, low bandwidth, heterogeneous network)
- Application Characteristics (Real time, Non-real-time)
- User mobility (cell mobility, subnet mobility)
Factors Affecting Mean Opinion Score:
MOS can simply be used to compare between VoIP services and providers. But more importantly, they are used to assess the work of codecs, which compress audio and video to save on bandwidth utilization but with a certain amount of drop in quality. MOS tests are then made for codecs in a certain environment.
There are however certain other factors that affect the quality of audio and video transferred, as mentioned in that article. These factors are not supposed to be accounted for in MOS values, so when determining the MOS for a certain codec, service or network, it is important that all the other factors are favorable to the maximum for a good quality, for MOS values are assumed to be obtained under ideal conditions.