Changing the conversation

“VoLTE is no different from any other new technology deployment, with one exception,” says Peter Carson, senior director for marketing at Qualcomm. “You’re talking about a service [voice] that has historically been the core business for the mobile industry, one that has been honed and refined over the past twenty years to the point where mobile telephony is virtually indistinguishable from wired telephony in quality and reliability.”

Having done so much to develop it, operators can ill afford to jeopardise a service that will continue to be a huge revenue generator, even as its contribution to overall income declines. (Informa Telecoms & Media has forecast that voice will account for more than half of all mobile operator revenues out to 2017, when global revenues are expected to hit $1.18tn, of which $604bn will derive from voice.)

And while the complexity of VoLTE might not mark it out as unique, it is hardly trivial. Problems with power consumption in the device, inefficiencies inherent in the LTE standard (due in part to its immaturity), interoperability and roaming challenges all combine to mean that VoLTE will “take years to work out, not months,” Carson says.

The gradual transfer of voice services from legacy networks to LTE—today in its earliest stages—will be a delicate and vitally important process.

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Qualcomm’s chipsets are involved in the early VoLTE deployments, in South Korea and the US, although the firm “understands the limitations of those deployments,” Carson says. The technology is probably most advanced in Korea, home to the most advanced and widely deployed LTE networks, but even here there are “basic blocking and tackling” interoperability issues.

“There is still a lot more to do before VoLTE becomes mainstream, comparable to 3G, or adds significant service enhancements that make it a premium service. We still haven’t seen anything that is anywhere close to mainstream,” he says.

VoLTE is necessary not because existing voice services are fundamentally flawed but because operators want to move towards a single network technology. Those early deployments are motivated by this drive to network consolidation and consequently the operators overseeing them are “running very fast witout any bells, whistles or anything that will distinguish them,” says Carson.

But VoLTE is also being sold on the improvements it can bring to service sophistication and network efficiency—and Carson is pragmatic in his assessment of both.

“Let’s put the efficiency in perspective,” he says. “You can make VoLTE more efficient but it’s very hard to design a VoLTE system that’s more spectrally efficient than 1x CDMA.”

In any case, he says, it’s not as if operators are trying to replace systems that are broken in terms of their capacity; the real drive is to accommodate growth in data. “Voice is a smaller and smaller portion of network traffic so any kind of efficiency gains you get from new voice technologies are going to get completely lost. To make VoLTE more efficient than 2G and 3G will take a few years, by which point the proportion of data traffic will be even greater,” he says.

When it comes to enhanced service offerings Carson agrees that IMS VoLTE will bring enhancements like presence, file sharing and IM that will represent “the next wave of customer experience in communications.” But , as he points out, OTT providers have been offering comparable services for some time.

Where operators have a real opportunity is in bringing to market truly universal, reliable iterations of such services, he says. And while that seamlessness, across networks and international borders, is where much of the time consuming complexity resides, mobile operators should not be disheartened.

Solving interoperability problems is what the industry is good at, he says. From SMS onwards, “they’ve done it every time with new services”. And that expertise offers operators the opportunity to create services that might not differentiate in terms of functionality can do so in terms of other key elements of the experience.

“Consistent QoS on a mobile handset, is a very challenging thing to achieve in a radio environment. That seamless mobility in terms of handover and roaming to other networks is the unique advantage that mobile carriers have. Even if similar services already exist, that interoperability, QoS and mobility is the opportunity.”

It would be enough of a challenge if every operator in the world was evolving at the same pace and from the same point but Qualcomm has identified 17 different solutions for voice provision on an LTE device, bearing in mind different legacy technologies and flavours of LTE.

For operators looking to move to VoLTE fast, like those driven by network consolidation, Single Radio Voice Call Continuity (SRVCC) is the best option, he says. “With SRVCC you don’t need a mature LTE network or ubiquitous coverage. SRVCC gives you a safety net and a handover in case of failure.”

Meanwhile Circuit Switched Fallback (CSFB) has the benefit of ubiquity—“it’s across every major handset that’s out there,” he says. And while some early movers form the CDMA camp opted for a dual radio solution, a second wave of CDMA deployments—Carson namechecks KDDI and Sprint—are looking to run with CSFB. “It’s an important mode and will be for several years to come—certainly that’s even more true for the GSM/WCDMA operators,” he says.

Handset capabilities and availability have always paced mobile technology and there are important device issues to address for VoLTE, Carson says. Chief among them is power consumption. “It is very complex to conserve power in a VoLTE call,” he says. “There are some features built into the standard, like discontinuous reception that allows you to shut your transceiver off in short intervals. But it’s very challenging to optimise for these short intervals because these devices don’t’ power down or ramp up very quickly. So it takes months, or even quarters, to optimise these algorithms to fully extract power gains, even from features that are designed specifically to preserve power.”

Nonetheless Carson insists that devices will be no more of a drag on VoLTE than any other link in the chain. “Almost every important KPI that you look at has an impact across multiple elements of the system. So any delay would be down to all of the different players in the ecosystem that are working together to solve problems in every layer of the system.”