Analysis of inter-Mean-Opinion-Score (iMOS) and QoS metrics for 5G Voice over LTE (VoLTE) and Voice over New Radio (VoNR) services over IP-Multimedia-Subsystem (IMS) in 5G mobile networks

At present, mobile network operators (MNO) need to improve Quality of Service (QoS) and Quality of Experience (QoE) of voice and video services to compete with over-the-top (OTT) Voice over IP (VoIP) applications. For an MNO to be able to provide HD voice and video calls, is essential to use a dedicated IP Multimedia Subsystem (IMS) network. The contribution of this paper is the analysis of measured data collected from real-time testbeds related to the fifth generation (5G) mobile network and then, computing the inter-Mean-Opinion-Score (iMOS) and QoS metrics for both 5G Voice over LTE (VoLTE) and Voice over New Radio (VoNR) services over IMS. Thus, there are evaluated QoS metrics throughout the communication stages among the User Equipment (UE) for the 5G Stand-Alone (SA) and 5G Non-Stand-Alone (NSA) networks. The obtained results show how QoS metrics like jitter and delay impact the iMOS results. The obtained results satisfy the requirement for VoNR and 5G VoLTE which show iMOS values greater than 4 out of 5 where 5 represents the best quality. The results were obtained in a controlled environment laboratory, using specialized radio test stations with non-interference outdoor propagation signals and lower path loss since can be used as a reference for upcoming research.