Pieter Veenstra, Lead Solution Architect, NetNumber

When Apple announced the support of Voice-over-WiFi (VoWiFi) in its new iPhone 6 series (and the iPhone 5 series and other Apple devices with iOS 8), it kicked off a lot of discussions. Although the principle of VoWiFi is not new, operators refrained from opening the VoWiFi service to the public because of surrounding issues like QoS and the support in devices. With Voice-over-LTE launched in many networks and the support of VoWiFi in Apple devices, the time has come for operators to pay attention to VoWiFi.

The timing is also right because of the growing appreciation of WiFi. Various speakers at BroadBand World Forum 2014 recently underlined this in their presentations:

  • WiFi gains importance as the primary and only mobile access in public areas like metro undergrounds, airports, and football stadiums.
  • Devices now support WiFi Certified PassPoint, which eliminates the need for users to find and authenticate a network each time they connect.
  • 60% of the mobile traffic is already via WiFi although 90% of our time we are at home/work/school… (i.e. we are moving only 10% of the time).
  • The supported bandwidth via WiFi is growing faster with new features like WiGig than the growth of cellular network capacity.

Will VoWiFi be as disruptive for the Telco voice services as WhatsApp was for their SMS revenues? No, even the opposite may be expected since VoWiFi is technically supplementary to VoLTE. The big exception is in the physical access whereby VoWiFi traffic is traversing over a WiFi access path and VoLTE using LTE radio access resources. But in the network, VoWiFi sessions are handled identically as VoLTE sessions are by the IMS Core.

And VoWiFi brings advantages to both end-users and mobile operators:

  • WiFi may solve the in-door coverage issues of LTE.
    • This offers a better in-door working voice service to end-users without the need to install complementary femto/pico radio cells.
    • As an extension of the network, operators need to invest less in the periphery of their LTE radio networks.
  • Mobile operators can offer a new attractive price model for their voice services with free calling when abroad, for example, as no roaming charges are involved when the voice calls are handled as data via WiFi.
  • A much better voice service quality compared to today’s 2G/3G mobile services.

Hence VoWiFi may further stimulate the use of Voice-over-IP (VoIP) services, making both VoLTE and VoWiFi the killer apps for the IMS Core investments by operators. This is why big mobile operators in the US are inclined to open their networks for VoWiFi. Operators in other continents cannot deny this trend, and many have plans to announce VoWiFI services shortly.

But the promise of VoWiFi comes with a price:

  • When WiFi becomes a voice-capable network for mobile devices in addition to LTE, VoWiFi will increase the network signaling load significantly. As WiFi coverage areas are normally much smaller than mobile cells or tracking areas, the associated signaling traffic is much higher, especially if the user is on the move.
  • The overall signaling complexity in the network further increases for the seamless hand-over of standing calls. This refers to situations when end-users are traversing between WiFi networks, exiting WiFi coverage (typically leaving the house, office, school, etc.) and calls need to be continued as VoLTE by the mobile cellular network.

NetNumber’s TITAN is a perfect fit for operators to cope with these effects of VoWiFi in their networks:

  • TITAN supports the full range of signaling and control functions in a single platform, thereby solving the signaling surge within networks.
  • TITAN offers a high-capacity transaction platform that far outnumbers the normal telecom server practices, and can be flexibly up-scaled up to 5,000 SIP call attempts per second (CAPS) per TITAN Edge instance.
  • TITAN has full programming flexibility with standard IMS functions by which it seamlessly integrates in existing IMS platforms to provide the extra functionality for the hand-over of VoWiFi sessions.

VoWiFi is viewed as promising service for end-users, device manufactures and the telecom industry as whole. It is hoped that the telecom operators will act swiftly to harvest this unique business opportunity. And the unique signaling and control capabilities of NetNumber’s TITAN will limit the network impact with the implementation of VoWiFi.

To learn more about how NetNumber’s TITAN may be used by operators to enable their network cost-efficiently for VoWiFi, contact sales@netnumber.com.

Categories: Blog


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