Practical Guide to LTE-A, VoLTE and IoT

4Comprehensive Performance Evaluation of VoLTE

4.1 Overview

Voice over LTE (VoLTE) has been witnessing a rapid deployment by network carriers worldwide. During the phases of VoLTE deployment, carriers typically face challenges in understanding the factors affecting the VoLTE performance and then optimizing it to meet or exceed the performance of the legacy circuit‐switched network (i.e., 2G/3G). The main challenges in terms of VoLTE service quality are the LTE network optimization and the performance aspects of the service in different LTE deployment scenarios. In this chapter we present a detailed, practical performance analysis of VoLTE based on commercially deployed 3GPP Release 10 LTE networks. The analysis evaluates VoLTE performance in terms of the Real‐time Transport Protocol (RTP) error rate, RTP jitter and delays, the Block Error Rate (BLER) for different radio conditions, and VoLTE voice quality in terms of Mean Opinion Score (MOS). In addition, the chapter evaluates key VoLTE features such as Robust Overhead Compression (RoHC) and Transmission Time Interval (TTI) bundling. The chapter provides guidelines for best practice in VoLTE deployment as well as practical performance evaluation in commercial networks.

4.2 Introduction

VoLTE is an IP Multimedia System (IMS)‐based voice service over the LTE network [1]. The IMS supports various access and multimedia services and has recently become the standard architecture of the Evolved Packet Core (EPC) [1, 2]. 3GPP has adopted the ...