Vodafone UK is now testing VoLTE services on its live network and due to provide an update on plans for a commercial launch of the technology, Light Reading has learned.
Earlier this year the mobile operator promised to introduce a commercial VoLTE service in the summer but it now looks at risk of missing that target, with just several days remaining before the summer season officially draws to a close. (See VoLTE Standoff in the UK, EE on Track to Launch VoLTE in Summer, Vodafone UK to Launch VoLTE in Summer and 3 UK to Launch VoLTE by September.)
"We continue to make progress on VoLTE and have now moved it from our labs for rigorous testing on our live network," a spokesperson for the company told Light Reading when asked about the status of VoLTE. "We will provide a further update on our launch plans soon."
Vodafone UK 's latest statement comes just a day after smaller rival Three UK became the first of the country's four network operators to introduce a commercial VoLTE service under the brand of 4G Super-Voice. (See Eurobites: Sigfox Hooks Up to Eutelsat for IoT.)
VoLTE allows operators to connect voice calls over the 4G network and is supposed to lead to improvements in call quality and a reduction in call set-up times.
Besides beating Vodafone to the introduction of a commercial service, 3 has also moved faster than EE , the UK's biggest mobile operator, which has also been aiming for a summer launch of the technology.
Light Reading has approached EE on several occasions for an update on its VoLTE plans but has not received any response.
Trading under the O2 brand, Telefónica UK Ltd. appears to be in less of a hurry on VoLTE, having previously told Light Reading it will conduct trials of the technology in the October-to-December quarter before launching services next year. (See O2 to Launch VoLTE in 2016 After Q4 Trials.)
O2 is currently the target of a £10.25 billion ($15.8 billion) takeover bid by Hutchison Whampoa Ltd. (Hong Kong: 0013; Pink Sheets: HUWHY), the owner of 3, and a merger of the two players would give rise to the UK's biggest mobile operator by customer numbers. (See Telefónica Seals $15.2B O2 Sale to Hutchison.)
Operators have previously used a technology called circuit-switched fallback (CSFB), which brings 2G or 3G networks into play when calls are made to or from a 4G device, but VoLTE could hold particular attractions for 3 and EE.
Neither player controls any of the sub-1GHz airwaves that authorities originally handed out for use with traditional telephony services and have instead had to rely on 1800MHz spectrum to support voice calls.
Unfortunately, these airwaves do not penetrate buildings as effectively as sub-1GHz spectrum, making it harder for 3 and EE to provide high-quality voice services indoors.
Both operators do, however, hold 800MHz frequencies awarded during the UK's 4G auction and 3 is now using this spectrum with VoLTE.
"By the end of the year, one million of our customers will have access to better indoor coverage and be able to use their phones in more places than ever before," said Bryn Jones, 3's chief technology officer, in a company statement yesterday. "We are proud to be the first network to roll this out across the country."
EE seems likely to follow suit, having previously flagged trials of 800MHz-based VoLTE in a part of rural Oxfordshire where existing coverage is poor.
Although EE and Vodafone are lagging on VoLTE, both operators have launched WiFi calling, a technology that allows mobile calls to run over WiFi connections and is similarly aimed at improving the quality of indoor services.
EE began marketing a WiFi calling service in April while Vodafone started offering the technology earlier this month. (See Can WiFi Calling Find Its Voice? and EE Hopes WiFi Calling Will Hit the Spot.)
Unlike VoLTE, however, WiFi calling does not appear to support handoff to other technologies, meaning a customer loses the connection when moving outside the WiFi hotspot.
Vodafone's spokesperson says the development of VoLTE has formed a part of its £2 billion (US$3.1 billion) network investment program over the last couple of years.
— Iain Morris, , News Editor, Light Reading