Rating: We’re obviously getting closer to real LTE
It’s frequently overlooked when discussing 4G networks that, besides providing high speed data links, such networks need to carry the boring stuff too – voice and SMS. Well, thanks to the VoLGA Forum, Deutsche Telekom claims it has made the first LTE phone call. Sadly, VoLGA is not alone.
The VoLGA (Voice over LTE via Generic Access) Forum isn’t the only one trying to tackle the thorny problem of how all-IP networks like 4G are actually going to handle traditional voice traffic and SMS. There are other initiatives.
VoLGA works by packetising voice via an extra element at the voice switching site – so it’s a half-way house for operators trying to ditch their existing switched networks and moving to a full IP network based on IMS (IP Multimedia Subsytem).
Sadly, VoLGA is far from being alone. There’s a way of cheating, for example. That’s called CS Fallback – a system which would instruct an LTE handset to ‘fall back’ to a GSM network when a voice call or text is required.
Of course you could go the whole hog and replace your entire infrastructure so the whole thing is genuinely all IP based using IMS for call set-up and session control.
Or there’s something called Fast Track VoLTE (voice over LTE) technology which Nokia Siemens Networks (NSN) is backing and introduces an IMS-like functionality to soft switches to handle voice over LTE networks.
NSN says it is aligned with something called One Voice which is another industry initiative for standardising how LTE networks will handle voice.
The trouble is that one day after Deutsche Telekom claimed to have made a VoLGA style call, NSN claimed it had made a voice call using Fast Track VoLTE in its own laboratories.
At least Deutsche Telekom used two independent test environments provided by Kineto Wireless and Alcatel-Lucent.
This has all the makings of a big industry battle. Whatever happens, we should still have some way of offering SMS services, though.
