China Mobile is deploying Voice over LTE (VoLTE) on its commercial TD-LTE network in Guangzhou ahead of a wider nationwide rollout. The company has tapped up local equipment supplier ZTE to deliver the project.

The VoLTE services will support enhanced single radio voice call continuity (eSRVCC), designed to allow switching for seamless handovers to non-4G networks. The eSRVCC implementation complies with the LTE-A 3GPP R10 standard and claims to greatly reduce latency times when switching voice services between a 4G network and 3G or 2G networks.

A recent demonstration of the service in Guangzhou showed off a newly built IP multimedia subsystem (IMS) system and 4G smartphones with Qualcomm Snapdragon 800 processors.

“The successful demonstration of the VoLTE service speeds up the development of the entire industry ecosystem,” said Mr. Sha Yuejia, vice president of China Mobile.

Mobile operators have long argued that voice revenues are declining at an alarming rate due to competition from OTT, commoditisation of voice and the data-focus of smartphones. However, voice is still the biggest revenue driver for mobile operators in developed and developing markets alike – and is expected to remain a very important service for mobile operators for a long time, even if revenues generated by data services overtake those generated by voice.

LTE promises to provide a more cost-effective, IP-based mobile voice platform that can eventually replace today’s circuit-switched alternative. VoLTE aims to provide a voice service that is at least as reliable as current cellular systems, over an all – IP network in a shared resource environment.

As voice codecs and standards evolve, the digitization of voice becomes more efficient and operators will be able to provide the same voice service quality (compared with 2G and 3G) more efficiently, thus being able to serve subscribers with less spectrum, which will free precious spectrum resources for other data services.

Telecoms.com Intelligence carried out a survey of mobile operators in 2013, where respondents were asked to assess a number of advantages to VoLTE technology and 38.5 per cent rated better network efficiency as Very Important. A further 37.5 per cent rated it as Important.

But it will be some time before the technology is widespread. More than half the respondents to the survey have yet to commercially launch LTE net works. Just under one quarter launched in 2013, with 14.2 per cent expecting to in 2014 and 16 per cent in 2015 or beyond.

The planned timing of respondents’ VoLTE launches reflects different levels of priority, as well as operators’ assessment of other factors. Almost one fifth of respondents want to get VoLTE into the market within six months of their commercial LTE launch. A further 29.3 per cent expect it to launch between six months and a year after their LTE network.

The largest share of respondents, 34.3 per cent, plan to introduce VoLTE between 12 and 24 months after LTE launch, while the remaining 14.1 per cent do not see it coming into service until at least two years after their LTE network goes live.