VoLTE Maintains Momentum

I wrote recently that IP Multimedia Subsystem (IMS) is operators’ preferred technology to support voice service in LTE networks, and that the IMS-lite "VoLTE" mechanism will be the first step toward implementing it. (See VoLTE to Drive IMS Renaissance?)

I considered this a noncontroversial, straightforward stance, but it generated some disagreement among Internet commenters. Generally the view was that Skype Ltd. already works, so carriers should just give it up and not provide their own telephony service in LTE. At least, that’s what I think they were saying. It’s not clear.

Meanwhile, consensus around VoLTE is building steadily. The sense from the recent Mobile World Congress was that the industry at large is solidly behind VoLTE. Many carriers would, of course, like someone else to iron out the (sizeable) wrinkles before they have to implement it in their own networks – base station schedulers and handset software, in particular, remain challenges – but the consensus is that VoLTE and IMS is the most viable option over the medium to long term.

One of the higher-profile network infrastructure marketing initiatives at MWC, for example, was an IMS-based voice and video calling demonstration by Verizon Wireless , LG Electronics Inc. (London: LGLD; Korea: 6657.KS) , Alcatel-Lucent (NYSE: ALU), and event hosts the GSM Association (GSMA) . (See MWC 2011: Verizon Plans VoLTE for 2012, Ericsson, Samsung, Verizon Try VoLTE and AlcaLu Shows VoLTE and Games.)

It is also the case that the industry does not view VoLTE and carrier-provided telephony as being in mortal combat with Skype, Google (Nasdaq: GOOG) Voice, Facebook Chat, or various other communities. There is some tension, inevitably, but in general carriers want their customers to use the services they like. That’s the point of being a mobile data provider. Skype’s run of success with mobile operator collaborations is evidence enough of that.

Verizon Wireless made this very point during a briefing at MWC. The carrier is strategically committed to VoLTE and the evolution to rich media “RCS-like” services using IMS. But its stance, at least as I interpreted it, is certainly not one of hostility toward third-party services, or paranoia that it will be somehow be disintermediated. Instead, its aim is to embrace third parties and add to the user experience by extending the reach, quality and overall usefulness of these services.

The carrier sees its IMS core as a foundation technology that would allow it not only to develop its own services, but also to act as a bridge between disparate, non-interoperable, communities – Skype, Google Voice, Facebook, or whatever else becomes popular. Over the longer term, as the Evolved Packet System (EPS) bearer model matures, there is also potential, according to Verizon Wireless, to expose network QoS to third parties via standardized APIs, to allow applications to move from best-effort performance on default bearers to a guaranteed service class on par with the carrier’s own offerings. (See LTE & QoS.)

Whereas the PSTN is the “interconnect of last resort” today – the glue that connects virtually everyone on the planet – a new approach is required for interoperable, IP-based, rich-media communications in the 4G era. With IMS core networks, Verizon and other carriers are positioning to fulfill this role in LTE.

— Gabriel Brown, Senior Analyst, Heavy Reading

For more information about Heavy Reading's "Voice Over LTE, IMS & the Future of Rich-Media Services in the 4G Era," or to request a free executive summary of this report, please contact:

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