Voice over LTE now ‘ready for widespread commercial deployment’

The path to all-LTE networks just got cleared up a bit. After Qualcomm and Ericsson announced the handover of a voice call from the ‘4G’ standard to 3G back in February, Huawei and T-Mobile Austria – and Qualcomm again – have revealed a much smoother transition that should actually lead to commercial deployment this time.

Why is this important? Because LTE has only seen a patchy deployment so far. The networks know how to do all-IP Voice over LTE (VoLTE), but that’s of limited use if the call dies as soon as the user steps out of LTE coverage. VoLTE only makes sense if the users can continue the call while switching between network types, without noticing.

It’s a virtuous circle. Once VoLTE becomes viable for operators, phone manufacturers can start building their phones around it. Gradually, they will be able to stop putting 2G and even 3G voice capabilities into their handsets, which will make it viable for operators to turn off those old technologies and reuse the spectrum for 4G.

And it’s the smoothness of the handover that’s crucial here. The demonstration back in February used a technology called Single Radio Voice Call Continuity (SRVCC), and involved a pause of more than a second while the call was handed over. This time we’re talking the enhanced version of that tech – eSRVCC – and the pause is less than 300ms.

Huawei actually announced a successful test of eSRVCC a month ago, but this latest work with T-Mobile Austria took place in the field, rather than in a lab.

“Our successful pilot project showed that not only rapid data transfer, but also Voice over LTE technology is ready for widespread commercial use,” T-Mobile Austria CTO Rüdiger Köster said in a statement.

The company added that voice quality should see a boost from the switch to VoLTE, too.

So, when are we going to see that widespread commercial use in Europe? According to a Huawei spokesperson, that depends on how long it takes manufacturers to make their handsets VoLTE ready, but the aim is for the end of 2013.

Incidentally, this development may help put into context some of the changes about to hit MetroPCS’s VoLTE play in the U.S. As Kevin has noted, T-Mobile intends to do away with MetroPCS’s CDMA system and is sounding pretty cool on that carrier’s existing VoLTE implementation.

T-Mobile will be rolling out its own LTE services in the U.S. in late 2013, and it sounds like that timing will gel quite nicely with its adoption of eSRVCC.