VOLTE FEATURE
And if Kineto’s Shaw thinks users won’t be happy having their video streaming interrupted to take a call, Warren believes they’re even less likely to tolerate a bad voice service. “Unless it’s an OTT service that fully integrates and works out of the box, there are still a lot of people out there who want high-quality voice provided by an operator,” he says. One of the best things about the Verizon demo, according to Warren, was the use of AML wideband and high-definition voice, something he believes end users will see as a real benefit going forward. Kevin Mitchell agrees, saying that IMS architec- ture is carrier-grade, not OTT or best effort. “There’s a view out there that voice has become the domain of OTT, some kind of arbitrage or dial-around that doesn’t involve the service provider in the revenue stream, but IMS is VoIP,” he says. “Service provid- ers using IMS have control over the access network, policy control
mechanisms...they’re deploying different technologies throughout the access and core networks to make sure its carrier grade.” According to Mitchell, OTTs can bring a lot
of innovation to an all-IP environment, but at basic levels of QoS, compliance and emergency services offerings, they’re not in anywhere like the same category as traditional opera- tors. As Eric Ericsson puts it, OTT services are “at the telephony and service layer, but aren’t specified in using the lower layers for optimised media handling, policy control and radio capabilities. That’s why VoLTE, in terms of robustness, will work differently and better than a service running OTT.” While Mitchell sees a future in a service
federation model—where OTT players and carriers such as Skype and 3/Verizon/KDDI offer hints of how the two sides might co- operate at the network as well as the business level—Warren argues that there’s plenty of room for operators to go it alone on the VoLTE front. “Companies aren’t going to invest in the IMS core just for voice,” he says. With opera- tors evolving their service offerings in order to compete, it’s only a matter of time before people are persuaded of the value of voice calls plus the entire IMS-enabled infrastructure built around it, he argues. “Give subscribers the capability to do in- stant messaging in a way similar to SMS, give them presence information and data relating to what the person they’re calling is able to do with their phone—like a classic rich content suit (RCS) model of a contact list—promote
interaction between users and their contact lists in ways they might not otherwise have done,” says Warren. “Ultimately that drives up call volumes.” And, presumably, revenues. For Ovum analyst Steven Hartley, while
voice is becoming commoditised and isn’t gen- erating revenues in line with volumes, neither is data. The key strategic objective as voice moves on to LTE, he says, will be “managing costs effectively to ensure margins are pro- tected, even if revenues are under pressure.” Ultimately, says Hartley, operators will charge access fees that include bundles of minutes, text, data and whatever else they want to throw in. What proportion goes to voice or any other element is actually irrelevant, as long as the whole is making a profit...” In many ways, VoLTE represents a real opportunity for carriers to transition into the smart pipe stage by differentiating them- selves on voice and services related to it. As Dan Warren puts it, operators are definitely chasing more bandwidth. In terms of how or what they do with it, there aren’t really any right or wrong answers, just “answers based on each individual market and their spectrum availability and their map for technical evolution.” For operators calling time on carriers’ rel-
evance in the face of CSFB vs OTT, it’s worth taking a couple of steps back. Yes, there are a lot of players moving very quickly but devices are limited and, as Warren points out, they’re essentially de-bugging LTE on the fly. If VoLTE isn’t 100 per cent there, it’s only fair to point out that neither are the LTE deployments or the handsets that will take advantage of them. Sounds like a good time to bridge the IMS gap... n
Four myths about LTE
Stephen Hayes, principal engineer at Ericsson and chair of the 3GPP’s systems group has said there are four myths surrounding LTE and its capacity to carry voice. According to Hayes, these myths—and the realities—are:
• LTE is data only: Support for voice was one of the key considerations in designing LTE. The solution for LTE is IMS VoIP and it is fully specified.
• SMS isn’t supported over LTE: LTE and EPS (evolved packet system) will support a rich variety of messaging applications—including SMS. The solution is twofold, covering both the full IMS case and a transition solution for those networks that do not support IMS.
• IMS isn’t ready for prime time: IMS was first developed as part of 3GPP Release 5 in2002. It is based on IETF protocols, such as SIP and SDP, that are very mature. These technologies have been embraced by the industry as the signalling mechanism for multimedia applications.
• LTE doesn’t support emergency calls: VoIP support for emergency calls (including location) are included in Release 9. A transition solution—fallback to 3G/2G has existed since IMS was introduced in Rel5.
Mobile Communications International | First for news, best for business 33
In many ways, VoLTE represents a real
opportunity for carriers to transition into the smart pipe stage by
differentiating themselves on voice and services related to it.
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