Enter VoLTE — and IMS

Carl Weinschenk

The news during the past year or so has been the explosion in creation of 4G Long Term Evolution (LTE) networks by AT&T, Verizon and other companies. Establishment of those networks has become such cookie-cutter affairs that their launch in a particular area has become no more than local news.

The next great phase is upon us, however. It is an era in which the demarcation between wired and wireless networks will disappear and creative new services will be deployed in a manner that is far easier than it has been to date. Welcome to the world of the IP Multimedia Subsystem and the Evolved Packet Core (IMS and EPC).

IMS and EPC operate deep within the network. The first harbinger of the change that will be visible to subscribers is the deployment of voice services over the LTE networks. All of the information that flows across a network is data, of course. But to this point, LTE networks have not handled the exacting demands of data that comprise voice calls. That changed last month when Voice over LTE (VoLTE, pronounced “volt-tee”) arrived.

This must be important, since there actually was a race to see which network could claim to be the first to offer VoLTE. To most people, it wasn’t exactly as important as the race to the moon between the U.S. and the Soviet Union, but it seems to have been about as hotly contested:

  • On August 7, MetroPCS launched what it claimed was the first commercial VoLTE service and the LG Connect 4G Android smartphone, which it says is the world’s first VoLTE-capable handsets. The launch is in the Dallas/Fort Worth area.
  • SK Telecom, South Korea’s largest operator, said that it sold the first VoLTE phone in a store in Seoul on Aug. 7. The carrier said that it will upgrade its service to VoLTE for the rest of its subscribers in the coming months.
  • Various media reports said that LG Uplus, the third largest carrier in South Korea, also launched during the same week. The project, the reports say, is in conjunction with Ericsson.

The importance of VoLTE will be felt at many levels. At the highest level, the ability to use the LTE network for everything means that the need for the 3G network infrastructure — and perhaps earlier networks, if they still are in use — no longer exists. The bandwidth locked into those can be used for other purposes.

The efficiencies baked into VoLTE can make more attractive services available. For instance, VoLTE, experts say, can support high-definition telephony. It is more spectrally efficient and will help mediate, at least to a great degree, the great explosion of bandwidth demand.

The immediate gains are great. “LTE is much more efficient in dealing with voice in 2G and somewhat more efficient than voice over 3G,” said Madan Jagernauth, the vice president of marketing and strategies for Mavenir Systems. “For a particular voice conversation, it uses less resources at an equal or lower cost.”

Enter IMS and EPC

Those are solid benefits, but the main reason that VoLTE is considered by those in the know to be a key technical step is a bit more subtle: It’s a bridge to a whole new approach to networking. VoLTE is the first service that makes broad use out the IP Multimedia Subsystem (IMS). This is a platform that telecommunications companies have been cooking up for a half-decade, and it represents a basic shift in how networks operate. It generally is considered to be the future. “The groups I work with seem to think the only consistent way forward is to support VoLTE,” said Neil Wiffen, the principal analyst for Red Banana Ltd.

As the name implies, IMS utilizes the packetization of data that has been an ongoing process for years. Using IP as sort of the Esperanto of networking, IMS melds wired and wireless transport together. The bottom line is that carriers and service providers will look at one converged network for all the transport and services that they offer. Internal management of networks and services and outward-facing requirements such as roaming will become far more efficient.

It isn’t easy, though. Implementation of IMS requires significant infrastructure changes, so adoption is a long slog. Jagernauth said that the launch of VoLTE — which requires the implementation of an IMS core, a telephony application server and many other changes — is demanding. And it’s a flash cut. “All of that has to work seamlessly on day one,” he said. “It’s a major change in the way voice service is delivered.”

The bottom line is that the transition from a hybrid network — voice on 2G or 3G and pure data services on LTE — is wasteful and inefficient, but transitioning is an intimidating job. Wiffen said that IMS — which is one implementation of what is known as the evolved packet core (EPC) — can support 2G and 3G voice. Thus, even carriers without immediate plans to deploy VoLTE can set themselves up for the efficiencies and additional services that new visions of the network will bring.

VoLTE, however, is vitally important. There is nothing better than a “killer app,” which is a service or application that is a proven winner that can pave the way for more speculative or niche applications. The same basic platform that supports VoLTE can support any number of futuristic, speculative or highly targeted services. All are just modules on the same basic platform.

The bottom line is that the time has never been better for carriers to move into the future. “A lot of carriers are at the crossroads right now,” said Ken Kolderup, the chief marketing officer for Kineto Wireless. “What is their strategy for the next couple of years: Milk SMS and wireless [as currently configured] for as long as they can or try to keep up with the Joneses and innovate?”

Experts say that the switch to VoLTE is an important step in the evolution of the entire telecommunications infrastructure. The fact that the three carriers — though they are geographically widely separated — have made the move to VoLTE at the same time is a sign that this transition has fully entered the deployment and implementation phase.

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