WiFi Talk


fon wifi talk

Fon’s WiFi Calling service for voice and messaging over WiFi networks (VoWiFi)

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WiFi Talk provides calls and texts over WiFi when cellular coverage is poor or nonexistent, granting enhanced indoor and rural area coverage without the need of high mobile network and frequency license investments.

WiFi Talk is essential for telco Operators to provide an “always best connected experience” to customers who will be able to make and receive calls and text messages wherever there is a WiFi spot, regardless of 3G/4G quality coverage. Compared to apps like Skype or Whatsapp, WiFi Talk makes life easier by providing this connectivity seamlessly.

Major global mobile operators and device manufacturers such as Apple and Samsung are increasingly betting on WiFi Calling.

A worry-free roaming enabler

With WiFi Talk, customers can make and receive calls when abroad, without the fear of bill shock. Traditionally exaggerated roaming charges have shaped traveller behaviour, who have often simply turn off their phones or rely on OTT apps. WiFi Talk enables your customers to make calls and stay connected everywhere with your own value added services, reducing third party intervention.

Benefits for your customers

Increased reach: customers can make and receive calls & SMS when they are not under cellular coverage


Always best connected experience, over available RANs


Same user experience: customers use their handset in the same way as they usually do (from their dialler) without having to download OTT apps, create new accounts, or buy additional credit


Cost effective calls when roaming: traditionally exaggerated roaming charges have forced travellers to simply switch off their phone when abroad or rely on other communication apps (Viber, Skype, Whatsapp)

Benefits for you

Enhanced indoor and rural area coverage


Enhanced customer experience and NPS which directly translates into churn reduction


Same charging models as cellular voice can be applied


Get back in the driver’s seat: OTT less important for subscribers


Minimise cellular costs by Offloading to WiFi fixed infrastructure. WiFi represents between 4-10 times lower costs in data generation


Large savings on roaming interconnection charges


Increased revenue:

  • Priced as an additional service
  • Included in premium plans


User Story

fon wifi talk

I have terrible cellular coverage at my workplace.

I connect to WiFi there, and my data centric services (Whatsapp, email) work fine, I but keep missing incoming calls and texts, which really annoys me

Fon wifi talk

I could use Skype, or Whatsapp calls… but it is not the same

Fon Solutions wifi talk

WiFi Talk allows me to receive and make calls and texts over WiFi like over cellular.

Fon’s WiFi Talk Architecture

Fon’s WiFi Calling solution assumes an untrusted non-3GPP access, implying that the mobile operator does not need to know anything about the WiFi network the customer is connected to. Nevertheless, security is always guaranteed through an IPSec/IKev2 tunnel session. Mobile operators can implement WiFi Talk without even needing to deploy a network of hotspots.


Fon’s WiFi Talk service is based on 3GPP architecture for this type of access, allowing Fon’s partner’s network (Open EAP SSIDs) to be part of mobile operator’s WiFi coverage, locally and abroad.


When using the service, the user will associate to the WiFi signal, triggering user authentication process (WISPr or Captive Portal for Open SSIDs,  EAP for EAP signals). Whether user is connecting locally (in any of Service Provider’s network of hotspots) or roaming in any of Fon’s partner’s networks, his authentication request will be routed to service provider’s dedicated Fon Enhanced AAA server, using Fon’s Roaming Radius if needed.

Fon Enhanced AAA queries service provider’s authentication servers using RADIUS protocol to give access to the user; It also manages session accounting taking over the control level of user’s connection.


Once the user is granted access to the WiFi network, the device will establish an IPSEC tunnel against service provider’s ePDG, enabling the use of WiFi calling services on any hotspot belonging to Fon’s partner’s network.


Additionally, if the user is connected through EAP-SIM/AKA/AKA’ methods, Fon Enhanced AAA could interface directly with service provider’s 3GPP AAA using SWd DIAMETER protocol as well as with service provider’s Offline Charging System (OFCS) through a Gzn DIAMETER, allowing user’s WiFi calls to be charged like cellular.


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