Vodafone Germany claims to have beaten its rivals to the rollout of a VoLTE service and says it will soon begin selling VoLTE-compatible smartphones from device makers including Samsung, Sony and HTC.

The announcement comes days after Vodafone UK unveiled plans to switch on a VoLTE service in the summer and with rival operators plotting their own launches of the voice-over-LTE technology. (See 3 UK to Launch VoLTE by September.)

Asked for its response to Vodafone Germany 's move, German incumbent Telekom Deutschland GmbH told Light Reading that it plans to start selling VoLTE handsets by June.

In a statement published on the eve of the CeBIT tradeshow in Germany, Vodafone said it was currently rolling out VoLTE in Hanover -- the city that hosts CeBIT -- and that services would be made available across the entire 4G network, which now covers about 70% of Germany's population.

However, it remains unclear whether customers can already subscribe to a VoLTE offering from Vodafone, and the operator had not responded to queries on this point at the time of publication.

With VoLTE, Vodafone would be able to run voice calls made on 4G devices over its LTE network instead of routing them over its 2G and 3G networks, as it does currently using a technology called circuit switched fallback (CSFB).

Operators are keen on VoLTE because it should allow them to improve call quality for customers and reduce the time it takes to set up a call. According to Vodafone, it takes as little as two seconds with VoLTE to connect calls after dialing a number or clicking on a contact.

Vodafone also reckons the technology will be kinder to batteries than CSFB, describing this as an "energy-intensive switch over into the 2G or 3G network."

Cost savings may be another incentive for deploying VoLTE. Vodafone says the technology takes up less space in its basestations than other voice systems, allowing it to realize energy savings of up to 30% per base station.

For UK operators, VoLTE could also be a way to overcome the problem of weak 2G coverage inside buildings and in less densely populated communities.

Mobile signals travel more effectively over sub-1GHz airwaves, but EE and Three UK lack any of the 900MHz airwaves originally awarded for use with 2G voice services. The use of VoLTE in conjunction with the 800MHz spectrum they received during the UK's 4G auction could support a higher-quality service for customers.

Want to know more about 4G LTE? Check out our dedicated 4G LTE content channel here on Light Reading.

In Germany, Vodafone does not appear to be at a similar sub-1GHz disadvantage, but VoLTE could still become an important battleground for operators fighting over mobile customers.

Vodafone has lost its market share lead to Telekom Deutschland in the last couple of years and may hope a first-to-market advantage on VoLTE will help it to win back some business.

But it may have to move fast on commercializing the service to see off VoLTE competition from Telekom Deutschland. "We have already implemented VoLTE in our network," a spokesperson for the German incumbent tells Light Reading. "We are currently conducting more tests … and expect that in the first half of 2015 VoLTE enabled handsets will be available in the German market and we can start the deal."

Like Vodafone, Telekom Deutschland believes it will be able to provide much higher-quality voice services to customers through the use of VoLTE, describing it as "4K for the ears" in a reference to the ultra-high-definition TV technology.

According to an update from the Global Mobile Suppliers Association (GSA) published in January, Telefónica Deutschland GmbH is also deploying VoLTE services.

Following its recent takeover of E-Plus Service GmbH & Co. KG , Telefónica is now Germany's biggest mobile network operator by customer numbers.

— Iain Morris, , News Editor, Light Reading