ZTE says that it has completed the world’s first end-to-end voice over TD-LTE (VoTD-LTE) call in partnership with China Mobile and Marvell Technology Group.
The VoTD-LTE call was conducted on China Mobile’s network in Guangzhou, which deploys ZTE’s TD-LTE technology and core IP Multimedia Subsystem (IMS) platform. The end-to-end VoTD-LTE call was carried out using 5-mode, 13-band smartphones powered by Marvell’s chipsets.
At present, there are three main methods to offer voice services to LTE users: circuit switched fallback (CSFB), dual standby and VoLTE. The CSFB solution requires operators to hand off voice calls to slower 2G or 3G networks. The dual standby solution requires terminals to support the 2G/3G and 4G services simultaneously, with the 2G/3G network dedicated to providing voice services. VoLTE is an IMS-based voice service with voice transmitted as IP data and can be entirely supported by the LTE network without 2G or 3G networks.
Compared with the CSFB and dual standby solutions, the VoLTE solution offers superior voice quality and lower latency with improved energy consumption for terminals, delivering a better user experience for 4G services. Therefore, VoLTE is considered as the ultimate goal of evolution for LTE voice solutions.
Compared with 2G and 3G networks, VoLTE features higher spectral efficiency in voice services, which enables operators to support a greater number of voice users for the same amount of spectrum. Although the voice data is transmitted through IP packet data, VoLTE offers better user experience than 2G and 3G voice service. Performance is also superior to over-the-top (OTT) services as VoLTE features carrier-class QoS and HD codec technology. For operators, VoLTE enables the integration of data and voice services in a network, helping them reduce the complexity of Operation Support Systems (OSS) and achieve greater efficiency.
As mobile devices, TD-LTE wireless networks and IMS platforms become more mature, more VoLTE services will be deployed.