In some countries there's fierce competition between network operators, and the media is anually reporting about the performance of the networks. To come up with meaningful values, they perform yearly drive tests on their own in cooperation with field test companies. Reported values are then for example call setup success rates, call setup times, call drop rates, average and hotspot data throughput in the networks, etc. When recently analyzing the results of such a test in more detail, it occured to me that it's likely to be a challenge to match call setup success rates that are today beyond 98% and call setup times of less than 7 seconds (mobilt to mobile) once there is one method or the other deployed for Voice over LTE.
The challenge will be to match all of those values, be it call setup success rates, call setup times and also the drop rate when the call is handed over (or not) to a 2G or 3G network at the LTE coverage border area. CS fallback for example is unlikely to match any of those values as it is undisputed that the fallback mechanism adds 2-3 seconds to the call establishment time on each side. Also, making the fallback a success in at least 97% of the cases is a challenge as the procedure either requires the UE to blindly drop to the 2G/3G network or a well configured LTE network with perfect neighbor relationships. In addition, good interworking configuration between the 2G/3G CS core network and the LTE core for the signaling exchange of incoming calls is required. Quite a challenge. VoLTE and VoLGA would probably do a bit better in this regard but I won't go into the details in this post, no need for a fight between the two sides today.
Think about it, what will happen if a network operator deployes a Voice over LTE solution and the values do not match those of the 2G/3G network today. It's going to be a bloodbath in the press. I can already imagine the headlines…