• 10/22/2015
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WiFi Calling: Ready To Take Off?

With AT&T and Apple iPhone support for WiFi calling, the technology is poised to go mainstream. Heres how it works and its potential enterprise ramifications.

WiFi calling enables wireless handsets to connect to a mobile carrier’s network through WiFi access points. With expanded support from more carriers and Apple, I believe it’s poised to become popular. It can provide better indoor coverage, avoids roaming charges while traveling out of the country, and can be used for messaging aboard WiFi equipped planes. It also doesn’t require the installation of apps such as Skype, Viber or WhatsApp to make voice calls.

The original standard that enables WiFi calling is Unlicensed Mobile Access (UMA), which means that an unlicensed spectrum network (WiFi) is given access into the mobile network. Some call this VoWiFi, but let’s just call it WiFi calling here. Newer variants include the IR-92 profile for Voice over LTE, which is used by Apple.               

Ericsson’s Consumer July 2015 Insights Summary report shows that globally, four in 10 of users are satisfied with indoor cellular connectivity experience, and three in 10 satisfied with voice call quality, coverage and reliability. WiFi calling is said to increase satisfaction for four out of five US users. 

Given the benefits, why hasn’t it yet taken the US users by storm? It was initially only offered by T-Mobile in the US (small market share), and few handsets supported it.Quality of the calls were reported to be shaky, with spotty handoffs from WiFi and mobile networks, so even T-Mobile has not actively promoted it, which led to a lack of awareness.

But changes are afoot! Apple started to support the technology on the iPhone in September 2014 and AT&T received regulatory approval this month to offer WiFi calling; it’s expected to release it later in 2015. Sprint launched a service in April and Verizon has said it intends to support it. T-Mobile updated its existing service to include HD Voice, improved WiFi/mobile handoffs, and support on Android, Windows Mobile and Apple iPhone. It also offers free in-flight text and picture messaging using the GoGo in-flight WiFi.

So it looks like pieces are in place for WiFi calling to become widespread, especially given the market share of iPhone and AT&T. However, it could pose some issues in the enterprise.

Most office networks have WiFi coverage, and may even support Voice over WLAN (traditional VoIP phones on WiFi). If WiFi calling takes off in the enterprise, the responsibility may suddenly fall on IT to support WiFi callers. Mobile phones are probably already allowed access to WiFi, so end-users may hop on and start using WiFi calling without IT realizing it while the end-users may expect high levels of service.

As a result, IT teams will be faced with addressing two items: signal strength and managing traffic.

Signals: Design of voice over WLAN is a careful process involving RF audit and site surveys, and the same may apply for WiFi calling, which ensures a strong signal and requires increasing AP density to every 50 feet.  WiFi AP vendors can assist in getting good office signal coverage suitable for voice traffic.

Traffic: Even though WiFi calling traffic is encrypted, there are some ways to identify the traffic flows and categorize them. An enterprise’s WiFi vendor can assist with appropriate settings (examples: HP Aruba’s AppRF and Ruckus Wireless SmartCast features)

In enterprise BYOD environments, appropriate authentication, device and app managers can control which devices use WiFi calling to prevent uncontrolled access, but not every group does that. For example, it may be appropriate to block new users from connecting to WiFi if there isn’t enough bandwidth capacity to service them. With 802.11ac, however,bandwidth should not be a problem.

In my next post, I’ll take a closer look at how enterprises can prepare for WiFi calling adoption.

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