On the face of it, voice is a disappearing species. According to the Ericsson Mobility Report, in 2010 voice traffic was 50% of data. By 2015, it had dropped to less than 5%. Voice still holds court in many ways, but its role has evolved to the extent that it has become an entirely new type of service. No longer is data an optional add-on service. Voice has become a data service, deeply embedded in a data-centric world, both in terms of subscriber usage models and infrastructure.
A striking sign of evolution is the disappearance of the distinction between voice and data ARPU. In many markets, most subscription plans (even pre-paid ones) include a mix of voice and data, which makes it impossible to allocate revenues to either. For most subscribers – especially the younger ones – voice is essential to have, but data is the primary and by far the most frequent use of their phone. Some subscribers no longer listen to voicemail and expect a text instead. Other subscribers do not pick up voice calls if they know they are not urgent or unless they are anticipated by a text message.
At the same time, perhaps ironically, operators are putting an unprecedented effort to ensure that voice continues to work in LTE networks as reliably as before, and that delivers a better QoE. VoLTE can be very reliable and provide excellent voice quality, but it is also complex to set up and operate.
Operators have to meticulously test and monitor its performance in LTE networks to ensure their networks use resources efficiently and subscribers get the QoE they expect. As voice and data become more tightly joined, subscribers’ expectations are increasingly converging, with data being required to have the same reliability and voice having the same ease of use and flexibility of data services. The operators’ task of keeping subscribers happy and on their network is getting harder, not easier, as they need to optimize the joint allocation of network resources both services. In a network running at capacity, this can be challenging.
Wi-Fi calling is pushing the redefinition of voice further. Wi-Fi calling is much more than voice over Wi-Fi in applications such as Skype, Viber, or WhatsApp. It is fully integrated within IMS in the mobile core, allowing subscribers to receive and make calls over Wi-Fi seamlessly, using their phone numbers, and all VoLTE functionality. For some operators, Wi-Fi calling has become an interim solution ahead of the launch of VoLTE. Wi-Fi calling extends coverage in difficult-to-reach indoor locations where Wi-Fi is commonly deployed, and allows for low-cost international roaming, but also encourages new business models that push a Wi-Fi first approach (e.g., Republic, Google Fi, but also operators such as T-Mobile who are aggressively pushing the use of Wi-Fi calling where it supports good call quality).
Wi-Fi calling is no longer primarily an expedient to pay less. Instead, it is transforming voice into a service that is interface-independent (for subscribers there is no difference in talking over cellular or Wi-Fi) and, by extension, it adds the last bit mobile phones need to in fact become interface independent. Wi-Fi already carries most data traffic on mobile phones, and Wi-Fi calling may extend this pattern to phones as well. Cisco VNI predicts that Wi-Fi calling traffic will be twice as high as VoLTE traffic by 2020. This does not mean at all that the relevance of mobile operators will be reduced, but their role will be subtly changed from providing voice service over a single interface to multiple interfaces, as they currently do with data.
Another slowly emerging but deeply transformative driver to change is the ability to route calls to non-SIM devices, heralded by Apple and Google. When combined with Wi-Fi calling, voice ceases to be tied to the mobile handset and becomes available across all mobile and fixed devices – tablets, laptops, desktops or even other mobile phones. This is what OTT voice applications have been able to do since inception: you can use Skype on any device you have, fixed or mobile. This was also an advantage that OTT applications had over carrier-operated ones and now mobile operators can leverage it too. On the other side, this change will weaken the link of voice service to a phone number (or more generally to a SIM-based infrastructure) and may open the way to mobile services that are no longer necessarily tied to a primary, mobile phone device, but may freely work across a set of devices the subscriber has, and that may be managed by non-cellular service providers (e.g., cable operators, Google, Apple).
As it truly becomes a data app, voice retains its uniqueness as a crucial service, but it gains the versatility we need to complete the transition of mobile services to center around a subscriber and not a handset.
If you are interested in sponsoring our upcoming Analyst Angle program: VoLTE, VoWiFi: voice comes to the fore, again, please contact Lindsay Franklin at [email protected].
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