As We have refereed Advantages of VoLTE there are some downsides of VoLTE. Operators and vendor development teams are focusing to improve downsides of VoLTE. More dropped calls...at least initially Voice over LTE is a new technology. And because it's new, it's likely that, at least initially, it won't work perfectly everywhere all the time. If you are benchmarking performance with 2G and 3G than definitely you will face higher call drops. Limited to certain devices. In order to make or receive VoLTE calls, both devices must include 4G LTE radios and be equipped with software that will allow the VoLTE function. No carrier interoperability.