Voice over LTE

Voice over LTE

  • November 2014 •
  • 30 pages •
  • Report ID: 2478649 •
  • Format: PDF
As an all-IP network technology, LTE does not support legacy services such as voice and SMS which have always run in circuit-switched mode with 2G and 3G. VoLTE was chosen in 2010 by the GSMA from several propositions as the official way of supporting voice and SMS on LTE networks but the road towards full implementation and deployment in the network has been a long one. Although most mobile network operators claimed early on that they would adopt the solution, the consensus was rather that waiting for it to mature, and for others to experience it, was the way to go. South Korean operators were the first to deploy the solution, starting in mid-2012 but most Tier 1 operators were more cautious. Verizon, for instance, has repeatedly delayed its launch of VoLTE. This was first expected to happen in 2013, but was then delayed to early 2014 and then further to September 2014. Now, at long last, the market seems to be moving and the year 2014 appears to have become the real starting point for VoLTE to take its place in the network. Since our most recent ‘Insight’ on the subject, NTT DOCOMO launched services in Japan in May 2014, to be followed by T-Mobile, AT&T and Verizon Wireless in the USA. So what has changed in 2014 to drive operators to finally launch their VoLTE services?

The multiple delays and hesitations of the mobile network operators in launching VoLTE are food for thought indeed, raising a raft of questions. What is at stake behind VoLTE? Where are the obstacles to its deployments? Is the device ecosystem ready or is it the infrastructure side that is lagging behind? What has been, what is, the strategy of the operators? These are the questions that we shall answer in this report.

Until now, there were two different solutions for operators in the absence of VoLTE when it came to providing voice and SMS services on an LTE device. It was a choice of either switching back to 2G or 3G to handle the service through Circuit Switch Fall Back (CSFB) or keeping two different radios alive with Simultaneous Voice and LTE (SVLTE), as is the case for CDMA operators such as Verizon.

While apparently simple to implement, those two solutions are less than ideal for a number of reasons:
- It increases signalling traffic to a significant extent as the user equipment (the mobile device) is constantly switching from one mode (LTE) to another. In the early days of LTE deployments, this even caused network outages, namely on the Verizon Wireless network. Even though infrastructures have been updated to better handle signalling, this is still a hurdle for network operators.
- It slows down the transition to LTE and requires keeping the 2G network active. Since 2G networks will still be in operation for a long time yet, especially for M2M usage, operators need to maintain resources for them, resources that are then not available for 3G and 4G networks. As LTE refarming is used increasingly by operators, it is of paramount importance in order to streamline importance and speed-up deployments.

The VoLTE-focused activities of the following companies and organisations are reviewed in some detail in this report, either in dedicated sections, or in substantive descriptions in the relevant narrative text.

Algérie Télécom (Algeria)
Apple (USA)
Bouygues (France)
China Mobile (China)
Everything Everywhere (UK)
GSM Association (international)
KT (South Korea)
LG U+ (South Korea)
MetroPCS (USA)
Orange (France)
SFR (France)
SingTel (Singapore)
SK Telecom (South Korea)
Sprint (USA)
T-Mobile (USA)
Verizon Wireless (USA)


We are very sorry, but an error occurred.
Please contact support@reportbuyer.com if the problem remains.