It’s not quite raining Voice over LTE (VoLTE) and HD voice at CTIA, but there’s a lot of talk about both technologies. AT&T and Sprint both discussed HD voice, Apple loomed large in more than screen size, and T-Mobile brought its own twists from Seattle.
AT&T Senior Vice President Kris Rinne said the carrier was working with others on enabling direct VoLTE calls between their respective networks. She also noted that the company is taking a market-by-market deployment approach with VoLTE, taking advantage of the ability to use enhanced Single Radio Voice Call Continunity (eSRVCC) for switching calls between LTE and 2G/3G networks without dropping the call.
Two interesting facts Rinne discussed were network configuration and interoperability. LTE network download rates are typically much higher than upload rate, so AT&T has had to adjust bandwidth to be more symmetrical to support VoLTE calling. AT&T is working with several other carriers on lab testing of VoLTE interoperability, but all-IP end-to-end requires SIP trunking and other adjustments.
VoLTE and HD voice interoperability agreements are already being signed across Europe and Asia, typically being done carrier-to-carrier or through an IPX (IP eXchange) service. U.S. consumers may tolerate non-HD voice calls for some time, but enterprise customers are likely to ask for HD voice interoperability given that some carriers and supporting vendors are pitching VoLTE as the (next try) replacement for the desktop handset.
Sprint says 16 million of its customers have access to HD voice. The company has 30 post-paid and 33 pre-paid HD voice capable handsets available for purchase at this time, according to Sprint’s senior networking officer. Sprint doesn’t plan on launching VoLTE until it can deliver a “solid’ experience, so that sounds like 2015 or later.
Apple’s 800 pound shadow came down with a crash on Tuesday. The iPhone 6 and iPhone 6 plus both support VoLTE calling, practically a requirement for AT&T, Verizon, and T-Mobile. Most U.S. carriers gave their due to the new IPhones supporting VoLTE and there are all sorts of sweetheart incentive deals being cooked up to move the bigger screen Apple devices. Earlier generation iPhones aren’t going to be officially supported, but I’m waiting to see if someone cooks up a “Jailbreak” version of iOS to support VoLTE on the iPhone 4 and/or 5S.
And no U.S. HD voice discussion would be complete without talking about the bikers from Washington, T-Mobile US. In its Uncarrier 7.0 event, T-Mobile highlighted its ability to conduct a seamless call hand-off between a VoLTE call and Wi-Fi. T-Mobile has done Wi-Fi calling forever, but it is placing a broader emphasis on its ability to use Wi-Fi to offload/supplement 3G and LTE network calling, as well as offering free overseas calling via Wi-Fi.
Take all of this week’s announcements into consideration and it is clear VoLTE has moved from the area of wishful thinking to actual deployments. The only warning I’d offer is compatibility issues – despite established international standards – are going to be a continuing sources of headaches for device manufacturers and carriers. The SBC community has its work cut out for them in the years to come.
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