In Mobile Communication have have 3 access networks. GERAN is the oldest one and it is used for circuit switch voice transmission but also for Packet Switched transmission(GPRS,EDGE)
Than we have UTRAN. Its used by UMTS and HSDPA. My Question now. Is UTRAN today used for old-fashion voice calls (not talking about SIP or something else)? or is it a data trasmission only network.
(by the way the third is E-UTRAN for LTE.)
I thought it would be useful to provide an updated answer to this question.
UTRAN was designed to carry both voice and data, as previously mentioned. However, while VOIP (packet-switched) voice services are certainly supported, it was the intention that most voice calls would be circuit-switched.
Now that LTE (EUTRAN) is the predominant radio access technology, packet-switched voice calling (VoLTE) is preferred over CS voice. This is a necessity since LTE is all IP based. (Some mechanisms such as CS Fallback are available to support the transition to VoLTE.)