What Will LTE Mobile Operators Do About Voice?

Though it isn't by any means a show stopper, mobile operators launching Long Term Evolution networks still are considering several different ways of handling voice services.

In some, perhaps nearly all cases, LTE will be introduced as a data-only service. Mobile handsets typically will be introduced gradually as consumers decide to jump from their 3G services to 4G. Aside from native 4G voice protocols, operators always have the option to default back to 3G for voice.

That's the way the communications business is: there are many "legacy" applications, processes and issues that must be incorporated when migrating to a next-generation network.

Voice and LTE – What’s An Operator to Do? | BMI-TechKnowledge