2014 has already been a breakthrough year for Voice over LTE (VoLTE). There are now estimated to be eight live VoLTE networks on the global market, with more expected to launch before the end of the year.
Countries quick off the mark with LTE deployments are now becoming home to the first VoLTE services, capable of offering consumers HD voice and faster voice call set-ups. The move to an all-IP based communications network brings with it major opportunities for carriers to enrich their service portfolio, with video calling and conference services being logical next steps.
Furthermore, the number of VoLTE-enabled handsets hitting the market is growing considerably, which could be set to snowball further if rumours that Apple is planning to support VoLTE with its latest iOS8 and iPhone are proved correct. The enhanced quality of service offered by VoLTE could be a compelling selling point to consumers, ultimately enabling those carriers which act first with VoLTE to race ahead of rivals in ultra-competitive mobile markets.
VoLTE therefore appears a no-brainer for any operator that has already rolled out LTE. Except, perhaps, for the fact that the technical complexities involved in upgrading networks to support the service are some of the steepest engineers have faced in decades.
A major migration
Presently, voice calls by LTE subscribers are made through circuit switched fall back (CSFB) to existing 2G and 3G networks. Not only does this prevent consumers from accessing LTE data services while on a voice call, but it also can significantly delay the call set-up time.
Enabling voice calls between two LTE subscribers requires upgrades to both core and radio networks. Ericsson has been helping a number of operators in their network deployment planning to introduce VoLTE services in coming years, and Kati Öhman, marketing manager and VoLTE expert at the vendor, has some advice to hand.
“Operators should deploy an IMS network to deliver the VoLTE service. They also need to optimise and tune their LTE radio network to secure good coverage of LTE to support the voice service,†she says.
With few operators advanced enough with LTE deployments to provide 100% coverage, interworking legacy 2G and 3G networks is also a must. “Network functions like CSFB and handover of calls from LTE to 3G need to be implemented to secure a high-quality seamless voice service for the consumers,†says Öhman.
The main challenge for operators, she believes, is transforming a circuit-switched network towards an lP-based IMS network. Essentially, operators need to migrate their entire voice machine on to a new IP platform.
Dell’Oro Group analyst Chris DePuy identifies three classes of equipment that service providers must deploy on the infrastructure side to support VoLTE: IMS Core, voice application servers and session border controllers.
“These three types of devices and software are used as building blocks for VoLTE. We expect revenues to grow in these areas in the future, but at the same time as these three types of technology get rolled out, we expect to see a decline in older technologies, such as media and softswitches,†he says.
Vendors that experienced success selling media gateways and softswitches are generally now leading the way with IMS Core. DePuy admits there is little differentiation among the vendor community serving VoLTE technology to operators, and that it is mainly in the hands of major players such as Ericsson, Alcatel-Lucent, Huawei and ZTE.
Yet as service providers re-architect networks to support VoLTE, there is opportunity to also purchase software from those same suppliers and embed it in the network instead of hardware. The buzz phrase being, of course, Network Functions Virtualisation (NFV).
“At about the same time as VoLTE is being rolled out, NFV is coming along,†says DePuy. “The obvious market strategy for a newcomer is to deliver a NFV system which is also capable of delivering the new system.â€
Although it wouldn’t make commercial sense to deploy NFV to a network solely for launching VoLTE, a dual-market transition is underway that could add further impetus for carriers to explore this service opportunity.
First movers
Asia and North America have become launch pads for the first commercial VoLTE services. The world’s first ever VoLTE service was unsurprisingly launched by 4G pioneers SK Telecom back in 2012. But few other countries worldwide have the breadth of network required to yet provide a useful service.
One notable exception is Japan, where NTT DoCoMo launched nationwide services in June. Its VoLTE solution utilised Qualcomm’s Snapdragon processor and enables SMS, HD voice, video telephony and single radio voice call continuity; designed to allow for a smooth transition between 3G and LTE.
The other notable exception is the US. MetroPCS leapt ahead of the pack by rolling out a limited VoLTE service as early as 2012, with the company subsequently acquired by Deutsche Telekom in 2013. The real test is yet to come though, as Verizon and AT&T reveal details of their more comprehensive VoLTE service deployments. Verizon, which has the largest LTE network in the US, is targeting a Q4 launch for its nationwide VoLTE service, but notably has pushed back the debut of its LTE-only handsets until 2016.
As part of its VoLTE service, Verizon will also offer video calling options, and has long-term plans to extend its Rich Communications Services to include large file transfer, group messaging and more extensive location sharing.
Not to be completely outdone by its fiercest rival, AT&T launched its VoLTE in select markets in the US in May. The service is available in Illinois, Indiana, Minnesota and Wisconsin, and offers HD voice. It is yet, however, to confirm when it plans to roll the service out nationwide.
DePuy believes that in large markets, such as the US, the first operator to launch nationwide VoLTE could spark competitors into action: “Once one provider turns on a full nationwide VoLTE service, it could have the ability to dramatically sway subscriber numbers their way,†he adds.
Relaunching voice
After trailing behind with LTE deployments, the VoLTE scene in Europe is unsurprisingly looking rather tepid.
One interesting case study, however, is UK operator EE. VoLTE forms part of the company’s wider £275 million investment to grow its voice business. It set the tone by recently trialling a voice-over-Wifi service, which is set to be launched this autumn.
The operator will also begin commercially trialling VoLTE at the end of Q1 2015, with the aim of a launch in Q2. There is sound logic behind a dual launch of voice-over-Wifi and VoLTE. Not only is there the potential of a seamless handover between the two services, but they both utilise the same technologies: “The technology invested in VoLTE at the core infrastructure is the same for voice-over-Wifi,†explains Tom Bennett, director of network services at EE.
Bennett admits that preparing EE’s network for VoLTE is the most complex challenge he has faced in his 12 years of working as a network engineer.
“The reality is that we are adding a brand new core network to our existing network, which is a major technical challenge,†he says. “This is essentially us relaunching voice.†Coverage, says Bennett, is one of the essential components behind a successful launch of VoLTE.
The operator is utilising its 800MHz spectrum to increase the geographical coverage of its data and voice network, and in particular extending connectivity to rural areas of the UK. “You need about 90% top coverage to do this right,†says Bennett
EE’s job over the coming months is therefore to prove that the technology is stable, that network reach is sufficient and that the VoLTE service can be comparable to its existing voice service. Which is why Bennett is not taking much notice of what EE’s competitors are up to: “I’m happy not to be a first mover. This is an integral service that requires a quality launch,†he says.
2015 is shaping up to be a definitive year for EE and the VoLTE market as a whole.
To read more on VoLTE and Policy and Charging Rules Function (PCRF) developments, click here.
