Watch our 1.5 minute video about Wi-Fi Calling and why operators should go “best-of-breed.
It’s All about Indoor Coverage
Is a smartphone a Wi-Fi device or a cellular device? People spend more time on Wi-Fi than on cellular with their mobile devices. Indoor coverage is a massive challenge for mobile operators, especially with the new energy-efficient building practices and 5G.
Utilizing cellular base stations for indoor coverage is like using street lamps to provide reading light for your bed. Why not use the bedside lamp that is already there? And similarly, why not use Wi-Fi for indoor voice coverage?
Wi-Fi is everywhere. People are already running the vast majority of their data through Wi-Fi. According to different studies, as much as 80% of all mobile data goes over Wi-Fi, and a significant portion of this is indoor traffic. This includes traffic from within people’s homes. Cellular networks have an increasingly more challenging time penetrating modern buildings, and those 5G networks running on high-frequency bands will not make things easier for them.
What if you could use all of the different Wi-Fi networks that users are connected to for transporting the voice calls that would typically go over the cellular network? Suddenly, mobile operators would be able to offer coverage for their voice services virtually everywhere people spend most of their time.
What are the benefits?
Wi-Fi Calling is just as seamless for the user as iMessage. Users will never have to consider whether or not they are connected to Cellular or Wi-Fi. Voice calls will work from anywhere to anyone.
For mobile operators, Wi-Fi Calling has become critical for customer retention, as subscribers in many countries are giving up their landlines.
Benefits to the End User
- Single, uniform voice dialer on their smartphone.
- Allows voice services over any Wi-Fi network (home, office, hotspots).
- Wi-Fi Calling provides better indoor coverage.
- Seamless call transfer between Wi-Fi and Cellular is supported natively in the devices.
- Roaming charges will be minimized if the operator uses the same business model as, e.g. T-Mobile. A call from anywhere in the world will be charged as a mobile call in your home mobile network whenever you have access to the Internet over Wi-Fi.
Benefits to the Operator
- Better indoor coverage compared to cellular macro base stations. This solves an increasing problem with the “radio-tight” modern building structures.
- Reduced churn.
- With indoor coverage, subscribers can give up their landlines. Mobile operators can expect higher customer acquisition rates by offering Wi-Fi Calling services.
- Operators can get back in the driver’s seat, making OTT players for VoWiFi less critical to subscribers.
- Wi-Fi is a low-cost solution to enhance voice service coverage.
- Operators do not necessarily even have to invest in Wi-Fi footprint. They can instead rely on existing Wi-Fi networks.
- Wi-Fi Calling shares the same voice infrastructure with IMS-based VoLTE.
What Are the Potential Drawbacks?
The introduction of Wi-Fi Calling also comes with a few challenges that needs to be adressed.
Wi-Fi Calling and Quality of Service
By implementing a Wi-Fi Calling solution, operators have to give up some control over the quality of service (QoS) for voice, as the traffic will go over networks they do not fully administer. However, through the ever-increasing capacity of Wi-Fi networks providing Gigabit speeds and Wi-Fi 6 providing the same scheduling mechanisms as cellular, QoS will in most cases, not be a significant challenge. Also, Wi-Fi Calling offers an alternative to cellular voice where the cellular network does not work at all or is of poor quality.
Wi-Fi Calling and Emergency calls
As with any Internet-based voice service, emergency service operators can have difficulty tracking the user’s location. Upon registration of the Wi-Fi Calling service, the user has to register a default location, usually the home address. Also, Smartphone vendors, such as Apple, have collected data mapping location information for individual Wi-Fi access points and will use that for emergency calls even if the user has disabled location services.
Voice over Wi-Fi (VoWiFi) has been around for a long time, long before Wi-Fi Calling. Voice calls have been transmitted over Wi-Fi either in the form of OTT applications such as Skype or as initiatives such as UMA and femtocells to enhance the reach of mobile voice services in subscribers’ homes.
From an operator’s perspective, the problem with OTT applications is that the operator loses control. From the user’s perspective, the call will be disrupted when moving between cellular and Wi-Fi. The UMA / femtocell initiatives have proven too expensive, lacking widespread support among phone manufacturers. In an ideal world, voice calling should be seamless for the user, built-in natively in the device, and work over any network connection.
The underlying technology was available for years before the introduction, but operators were initially hesitant. They wanted to protect their voice-related revenue, including revenue from roaming charges. However, new business models allowing for flat-fee voice services, combined with the insight that users will use OTT applications for calls as much as possible, finally removed the last obstacle.
In September 2014, mobile operator T-Mobile pioneered Wi-Fi Calling. This was a paradigm shift for VoWiFi, implemented with native support embedded in smartphones and working seamlessly through any Wi-Fi connection. Text messaging (SMS) also works in this way.
Learn more about Enea’s role in a total solution for mobile operators.
Technically, Wi-Fi Calling is Voice over Wi-Fi. But don’t mix this up with the VoWiFi over-the-top (OTT) applications that have been available for many years. Wi-Fi Calling is natively integrated into the smartphone dialer, which offers a seamless user experience. Whether you are connected to Wi-Fi or Cellular, the call will work. The call will typically continue without interruption when a user moves between Cellular and Wi-Fi networks.
This seamless user experience is obtained using an untrusted 3GPP Wi-Fi access connection to the mobile core. An IPsec tunnel is established between the handset and a tunnel terminating gateway in the mobile core, which is connected to the same packet gateway used for cellular communication. Thus voice data packets will end up in the IMS system handling the call regardless of whether they come from a Wi-Fi or Cellular network. It will still work for operators using the circuit-switched GSM for voice. However, in this case, the call will be terminated when users move between the networks.
Wi-Fi Calling reduces churn, a high cost for operators. This is the biggest driver for mobile operators. Mobile operators will also be able to reduce the cost of building out cellular base stations and femtocells, as Wi-Fi calling will take care of the indoor voice coverage.
Because it works transparently over any Wi-Fi network, including when the user is abroad, it means zero roaming costs for the mobile operator. Suppose the operator transfers these cost savings to subscribers by charging the same rate for domestic and international Wi-Fi calls. In that case, it becomes highly attractive to frequent travelers, creating significant potential for the mobile operator to gain new customers and generate more revenue.
We Have the Key to Your Wi-Fi Calling Service
It is not enough for the subscriber to be connected to a Wi-Fi network. They also need to be authenticated and authorized to use the Wi-Fi Calling service. This is the crucial role of Enea’s 3GPP AAA, which also offers features such as adding policies to the service. Read more details about Enea’s role in the total solution.
You Don’t Even Need Your Own
Mobile operators do not have to build their own Wi-Fi network or partner with Wi-Fi service providers. Wi-Fi Calling will work regardless as soon as users are connected to a Wi-Fi network.
However, there are many benefits to deploying your own Wi-Fi. Learn more about Enea’s Carrier Wi-Fi solution for operators who want to deploy their own Wi-Fi service to stay even more relevant for subscribers.