Verizon Wireless plans to roll out Voice-over-LTE (VoLTE) services nationwide in the U.S. in early 2013, according to industry sources.

The operator has been trialing the IP Multimedia Subsystem (IMS)-based application in two markets, which Light Reading Mobile reported in September last year. (See Verizon Working on LTE-Advanced Standards and When Will Operators Bolt to VoLTE?)

Now, a timeline has emerged for the operator's broader service launch plans.

According to Catharine Trebnick, VP at Northland Capital Markets, “VZW has two cities now trialing [VoLTE] and plans for national rollout in early 2013.”

Another source that requested anonymity supported Trebnick's claim.

Previously, Verizon has stated that it plans to launch commercial VoLTE services in 2012. The news of plans for a national launch in 2013 does not indicate that Verizon will not launch in 2012 as planned or that it will miss its launch target this year. The operator can still launch VoLTE services in some of its markets this year, and then roll out nationally next year. (See MWC 2011: Verizon Plans VoLTE for 2012.)

A Verizon Wireless spokeswoman said in an emailed response, "We’re continuing to work on VoLTE and the services it brings, and will share any launch or availability plans in due course."

Why this matters
Verizon's nationwide launch schedule set for 2013 is significant for VoLTE because it marks an endorsement of the new IMS-based application by one of the technology's biggest champions.

The timing also makes sense for Verizon strategically because the operator aims to have LTE coverage across its existing 3G footprint in 2013. By having such wide LTE coverage, the operator may have a smoother service introduction for VoLTE and avoid having to support complicated handovers of VoLTE services from the LTE network to the 3G network when users move out of LTE coverage areas. (See Verizon: There's No Stopping Our LTE.)

For more

• Operators Raise Voice Services on LTE
• VoLTE Maintains Momentum
• Ericsson, Samsung, Verizon Try VoLTE
• AlcaLu Shows VoLTE and Games
• MetroPCS Plots LTE Smartphones, VoLTE Trials

— Michelle Donegan, European Editor, Light Reading Mobile