System Level Analysis of VoLTE Capacity with Enhanced Machine Type Communication

In this paper, Voice over LTE (VoLTE) capacity for Enhanced Machine Type Communication (eMTC) is evaluated with system level simulations. The study concentrates on a high signal attenuation scenario which is applicable to various VoLTE indoor use cases, for example voice call connectivity for elevator emergency phone. Two semi-persistent scheduling approaches are presented and compared that are designed for keeping the end-to-end packet latencies below the delay budget. Due to physical channel repetitions used with eMTC, favorable conditions for semi-persistent scheduling are limited and thus the presented methods combine both semi-persistent and dynamic scheduling. The results show that signal loss caused by multiple wall penetrations has a significant impact on total VoLTE capacity, with the number of concurrently supported calls in a cell being around 15 with Adaptive Multi-Rate Wideband (AMR-WB) 6.6 kbps codec.