Voice over LTE (VoLTE) emerges as the basis for voice services in future cellular networks. At the same time, Quality of user Experience (QoE) assessment methods have notably evolved in the last years, especially for VoIP services. The question that rises is, are these models ready to be used for VoLTE? In this paper, we contribute to answer this question by: (i) providing a high level exploration of current objective non-intrusive models for VoIP QoE evaluation, (ii) highlighting the review of works aiming to improve the standardized E-model (ITU-T Rec. G.107 (06/2015)) and the examination of non-standardized solutions proposed by the research community, and (iii) bringing forth the challenges identified for the completion of a successful QoE evaluation approach according to modern VoIP services such as VoLTE.
Scheduling and Capacity of VoIP Services in Wireless OFDMA Systems