This guest blog post was written by Kai Ojala, CTO, Anite Network Testing
The requirement for VoLTE is to offer high-quality voice calls and video calls, which as a baseline requires wide LTE coverage. LTE networks fulfill this aspect – especially lower carrier frequencies are deployed globally (e.g. 700 and 800 MHz frequency bands). Operators will benefit from customers switching to VoLTE services by harmonizing voice services and getting better capacity out of the spectrum.
Voice calls in LTE networks can be handled using Circuit Switched Fallback (CSFB) and Voice over LTE (VoLTE). CSFB provides a mechanism to transfer an initiated voice call to legacy circuit-switched networks. VoLTE, on the other hand, is a fully packet switched technology which uses Voice over IP (VoIP) technologies. With the SR-VCC functionality voice calls made with VoLTE can be switched over to legacy networks when the user moves out of the LTE network coverage.