Wi-Fi Calling Becomes the New Competitive Edge for Mobile Operators in 2015, Says Aptilo

Wi-Fi Calling Becomes the New Competitive Edge for Mobile Operators in 2015, Says Aptilo Image Credit: Aptilo

By Johan Terve,

VP Marketing,

Aptilo Networks

T-Mobile broke all the rules with the introduction of next-generation Wi-Fi Calling in the US late 2014: from revenue models to deployment strategies, it’s a whole new world for carriers. Don’t underestimate the impact it will have on the industry. It’s a good thing, though, because change is exciting, creating opportunities for real innovation to take place.

Wi-Fi Calling… No Wi-Fi? No problem! -- At least not for mobile operators. Mobile operators can do Wi-Fi Calling without deploying a single Wi-Fi access point or partnering with a Wi-Fi service provider. The next-generation Wi-Fi Calling will work through any Wi-Fi network and primarily through the ones in our homes.

Don’t get me wrong; there are a lot of good reasons why operators should deploy a Wi-Fi footprint anyway. Offering Wi-Fi services is probably the best insurance policy a mobile operator can get to protect their core business in a Wi-Fi-centric world. We have seen from some of our most successful Carrier Wi-Fi operator customers that they tend to have a lower churn rate than their competition.


We are often very quick in giving Apple credit for new innovative things, and sure they have a critical component for next-generation Wi-Fi calling in their latest iPhone models. But, Wi-Fi Calling would never have happened if mobile operators hadn’t changed their business models for voice from charging for minutes to instead charging for data. Additionally, many operators have already adjusted their roaming charges to be more reasonable, so there is no revenue to protect there, either.

Johan Terve,
VP Marketing,
Aptilo Networks


Modern, energy efficient, buildings may reduce the cellular signal level indoors by as much as 30 db. What this means is that the cellular signal strength will be only 1/1000 of the signal just outside the house.

As more and more people give up their landlines and use their mobile phone as the primary contact to the world, they will be more open to switching to another operator if the connection is poor. But, with Wi-Fi now more or less in every home and other indoor environments, Wi-Fi Calling will come to the rescue and provide better indoor coverage for voice services. This makes Wi-Fi Calling a customer retention game for mobile operators.


The next-generation Wi-Fi Calling is founded on IP Multimedia Subsystem (IMS) that provides the capabilities to move from the traditional circuit switched transport of voice calls to the all IP-based voice-over-LTE (VoLTE). Many operators are moving over to IMS as we speak. The main reasons for this is that LTE is more spectrum-efficient than the previous technologies and once service providers can close down legacy voice networks and run everything on LTE, they can start to re-farm valuable spectrum to be used for LTE.

With next-generation Wi-Fi Calling, support for Voice-over-Wi-Fi (VoWiFi) is embedded directly into the dialer of new devices such as iPhone 6. If the operator has implemented VoLTE, this offers users a truly seamless handoff from cellular to Wi-Fi calls. It used to be that making a Wi-Fi call with e.g. Skype was great…until you left the Wi-Fi hotspot. Calls would drop as soon as you were out of Wi-Fi range. It was unavoidable for calls to drop, as there was no seamless handoff from cellular to Wi-Fi.

Next-generation Wi-Fi Calling addresses this issue. Calls will glide from cellular to Wi-Fi and back again without any interruption in service.


For operators that have already deployed IMS and VoLTE there is a relative low barrier to implement next-generation Wi-Fi Calling. They need to invest in a special gateway (a so-called ePDG gateway) that terminates the IPSec tunnel from the device. They also need a flexible authentication server (3GPP AAA) that authenticates the user for the Wi-Fi Calling service. Flexible is the key word here. We have seen from our 100+ Carrier Wi-Fi data service deployments that authentication frequently needs to include lookups from multiple existing systems to set the right policy for the service.

About The Author:
Johan Terve has more than 25 years of experience working in the IT industry, and spent the last 15 years in various CEO, VP and Director positions. He joined Aptilo in 2007 and prior to that he served as VP Marketing & Sales at Ingate Systems. In that position he succeeded in putting the company on the map as a leading global player in SIP-capable firewalls and SIP trunking solutions for enterprise Voice-over-IP. As Marketing Director for Nordic Datadistribution, a $130M company, he was responsible for all business divisions and corporate marketing and helped this major IT equipment distributor become the fastest-growing company in Sweden for four consecutive years. Terve started his career as a software developer and has a broad university-level education in business administration, psychology and economics.


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