Voice is a basic mobile service that generates significant revenue for the operators. Voice over LTE (VoLTE) is a packet voice service that differs from the previous 3G and 2G circuit switched voice and provides increased
functionality and performance. This paper compares VoLTE, 3G and 2G voice services and aims to show how the optimization of the VoLTE service makes a difference compared to straighforward or suboptimal solutions. The
device platform and its main components; modem and RF, are scrutinized.
Voice over LTE (VoLTE) offers basic voice services in the LTE packet network. The previous WCDMA (3G) and GSM
(2G) voice services were based on circuit switched networks. In the packet network a new network node which is not used for circuit switched voice, the VoLTE server, is introduced to provide the IMS services. In principle,
having a voice service available in all its radio networks (2G, 3G and LTE) enables an operator to balance the traffic load between the different radio systems and to utilize its spectrum asset efficiently