LTE gets a voice

The jigsaw pieces are all falling into place for LTE following this week's LTE World Summit in Germany. However, according to Rethink Research, "significant technical barriers still need to be crossed before most cellcos will commit to firm mass roll-out dates; and new approaches, notably femtocells, will be important to maximize return on investment".

One of the big questions around LTE is what is it actually for... is it a nice big fat data pipe or will it be the network for all services including voice? While Orange see it as a solution for mobile data, T-Mobile's Klaus-Juergen Krath, senior VP of radio networks development is adamant that "I don't think we should push LTE as a wireless DSL technology - it has much more than that. That's why we push heavily for early availability of all services, most importantly voice and SMS over LTE." According to Unstrung, 3 Group's technology director, Ed Candy, went even further commenting at the Summit that "In these difficult times, to go ahead with a technology that's service-limited is crazy. We don't know how this financial crisis is going to play out. I would be against [using] any technology that has fundamental holes in it."

It's this question of voice that is perplexing the industry right now, and given the comment above it's perhaps not surprising that T-Mobile, through the VoLGA Forum, is leading the charge to find the answer to the question of how to migrate voice services across to LTE. Backed by vendors such as Kineto Wireless, Ericsson and ZTE,* the VoLGA Forum is aiming to define the 3GPP solution for delivering Voice Over LTE (and done so via Generic Access technology, to complete the spelling out of the acronym).

While Orange's stance is understandable, given that there is a perfectly good network in the form of 3G that can handle voice so LTE can focus on data, the fact is that this approach would require the operator to maintain two distinct network architectures. The sprectral efficiency of LTE is such that there are already savings for operators simply by moving data traffic from 3G to LTE, but the big savings come when they can start to manage just one network. The VoLGA initiative is interesting simply because it aims to address the missing step ... i.e. how to actually manage the migration of voice and messaging services to LTE, without jeopardising the quality, experience and revenue currently yielded by voice services.

While the WiMAX faction fight an increasingly desperate rear-guard action, it seems clear that LTE has won this particular battle. However, it's equally clear the battle on what the peace looks like is already warming up.


* Ericsson, Kineto Wireless and ZTE are AxiCom clients. AxiCom handled the launch of the VoLGA Forum in March 2009.