IP Voice applications for LTE carriers


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VoLTE device support

Operators with their own 4G network can save costs by minimize roaming in other MNO 3G networks but face challenges to move all their subscribers to 4G due to the large number of non-VoLTE devices still in circulation. Similarly, 4G operators can cut costs by discontinuing their 2G and 3G network but face similar issues in how to provide services to non-VoLTE handsets.

According to GSMA[1] as of January 2019 there are currently 1218 phone models that are VoLTE capable. To put these figures into perspective there are currently about 23 000[2] different Android models in use, which means that currently only 5,3% of them are VoLTE capable. Many of the new devices sold today still lack VoLTE capabilities and similar devices will be around for a good five to even ten years from now.

The Unikie Voice 4G apps are designed for this fragmented Android environment. By supporting Voice apps, an operator can theoretically increase their device support from 5,3% to 96,5%[3] for LTE Voice services. The apps bring Voice services to any LTE capable phone running Android 4.4 or higher, either via a download from an application store or preloading. If a user is lacking VoLTE capabilities on their phone, they can download the app and start calling right away using their SIM, without the hurdle of needing to purchase a new phone to move to LTE based Voice services.

On iOS there is VoLTE support from iPhone 6 and above and using Voice apps bring support to all iPhone 5/s/c devices as well. This may sound like a small difference, but it still makes a big impact on the bottom line if it will allow operators to jettison their legacy networks sooner. Another driver for iOS Voice apps is the fact that not all operators get VoLTE support from Apple, and for them iOS Voice apps can provide LTE Voice services for all iPhone models starting from iPhone 5 up to the latest flagship models.


Utilize your IMS

The Unikie apps are fully compatible with standard IMS networks and do not need any additional VoIP servers to be installed or integrated to the network. The apps follow the IR.92 specification as far as possible, meaning they register with SIP to IMS, authenticate against HSS user information and support the default HD VoLTE codecs such as AMR-WB. Calls between the Voice apps and VoLTE devices work smoothly as do CS break-out or break-in calls without changes in the network. As calls are routed via the same network elements as native VoLTE there are no additional network integrations nor new monitoring or charging integrations and call KPIs for app calls can be seen directly from IMS as well.


4G Voice app feature set

The Unikie Voice 4G apps support main IR.92 features:

  • SIP Registration and Authentication
  • Call establishment and termination
  • SIP Early Media
  • SIP Preconditions
  • RTP & RTCP
  • SDP negotiations
  • Caller information display (picture, name, number)
  • Numeric dial pad with DTMF tone support in different modes:
  • Loudspeaker and Bluetooth headset support
  • Dynamic session and codec parameter negotiation
  • Jitter buffer support
  • Echo cancellation support
  • Voice Activity Detector (VAD)
  • Comfort Noise Generator (CNG)
  • Perceptual Enhancement (PENH)
  • Packet Lost Concealment (PLC)
  • Call hold, resume and swap
  • Call forking to multiple clients on different devices (sip.instance & GRUU)
  • Multi-party conferencing
  • Automatic call handovers between mobile data and Wi-Fi networks
  • + other IR.92 supplementary service (waiting, forwarding, barring)

With these features, the Unikie Voice apps offers a familiar and standard voice experience.

In addition to Voice features, the Unikie apps also optionally supports Video and Messaging:

  • Adding or removing Video during IP calls using session renegotiation
  • H.264 video codec support
  • Sending and receiving SMS over IP and MMS messages
  • Delivery reports for SMS and MMS
  • Group chat using MMS

With these additional features the full services of the IMS network can be utilized.


Launching 4G Voice

The preparation for VoLTE services involves cooperation with each phone manufacturer whose phones will be used. With Unikie Voice 4G apps, the same SIP stack runs in each device, whether it is Samsung, Huawei or Apple. This makes testing much easier and faster than a normal VoLTE rollout while still targeting much more devices.

Similarly, updates for apps is more frequent and fast-paced than firmware updates from OEMs. This allows an app-based Voice Service to use the latest Android versions and keep the Voice SW up-to-date at all times.

As of today, GSMA numbers show that 703 operators have launched LTE networks but only 168 have launched Voice Services in their LTE network. We hope to improve that figure in the coming years and make 4G Voice ServiceS available to all.

Unikie is demonstrating 4G Voice apps at MWC19 Feb 25th to 28th. Book a meeting in advance via app.sales@unikie.com to get a personal demo session at Unikie Booth 5C41.


[1] https://www.gsma.com/futurenetworks/resources/all-ip-statistics/

[2] https://support.google.com/googleplay/answer/1727131?hl=en-GB

[3] 96,5% of Android devices support Android 4.4 or above https://developer.android.com/about/dashboards/

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