Voice: A Comeback Story Worth Talking About – PART 1

It's time for voice to make a comeback

Welcome VoLTE, welcome back voice!

This is a true story, reminiscent of the dramatic rise-and-fall movie scripts that often receive Oscar nominations and awards. The protagonist in our story attracted worldwide interest and met with tremendous commercial success some years ago. But then an unexpected competitor appeared and our protagonist’s appeal, especially to the younger generation, began to fade. The decline became more prominent after a number of innovative rivals emerged and stole the limelight. With the end of the road gradually approaching, our protagonist chose the reinvention path: it was time to bounce back by copying rivals’ key strengths. And the story continues…

Our protagonist is voice*, the service that propelled mobile phones to remarkable success in the 90s. It was SMS that later became the unlikely killer app, particularly for youngsters. And when mobile data started taking center stage, it was Internet browsing on the one hand and Over-the-Top (OTT) apps on the other that pushed voice to the sideline.

Although a large proportion of revenue for mobile service providers worldwide is still driven by voice calls, many industry observers have condemned this ‘outdated’ service to a future of irrelevance or low significance at best. The tendency of the younger generation to rely on their thumbs or to consider voice only as part of OTT video calling would corroborate such affirmations.

But voice has made a comeback, and it is all because of VoLTE. As a packet-switched technology, VoLTE is more related to OTT VoIP than to the ‘traditional’, circuit-switched 2G/3G voice. In fact, with the introduction of Rich Communications Services (RCS) and capabilities that OTT apps have offered for a while, such as presence, VoLTE is transforming a service that has marginally changed in years. However, this is not an OTT offering but a native service that providers can prioritize and – to a certain extent – guarantee. With crystal clear sound, faster call setup and improved 4G device battery life, VoLTE could potentially be a game changer and also pave the way for an enhanced video service.

Of course, the introduction of new technologies is rarely straightforward. Early VoLTE deployments have been hampered by a variety of factors including proprietary IMS implementations, lack of capable devices and interoperability/roaming concerns. Furthermore, the complex nature of VoLTE was bound to give rise to challenges that the simpler and – after years of optimization efforts – stable legacy voice service has rarely created in recent years. Yet, engineering teams have relished these challenges.

Service provider engineers and expert services teams have been addressing the performance issues originating in different VoLTE domains, from core and IMS to radio access (RAN). Similar to the majority of mobile user experience issues, the RAN is the focal area when VoLTE call drops, call blocks, distorted sound, echoing, etc. are recorded.  Analyzing, correlating and resolving these issues has been essential in preparing for launch or improving the post-launch VoLTE performance.

The efforts of technical teams have reflected the deployment strategy of each service provider, which range from aggressive (‘launch and sort out issues as they arise’) to cautious (‘only launch when the service is at least similar to legacy voice’). In some countries, the early adoption of VoLTE has been facilitated by – the complementary for indoor environments and same IMS core based – voice over Wi-Fi (VoWi-Fi) or Wi-Fi Calling, which the explicit iPhone support popularized. Irrespective of the approach followed and the challenges encountered, one thing is certain: VoLTE offers a set of concrete benefits to service providers and their subscribers.

To be continued…

*For simplification, this blog focuses on the native mobile voice service rather than speech based communication in general. Most of the comments made about the waning importance of voice are relevant to both fixed-line and mobile communications.


  1. Posted March 4, 2016 at 8:04 am | Permalink

    I can’t really agree with this.

    There is nothing in VoLTE to suggest that it will drive more usage, let alone more revenue for mobile telephony. It isn’t intended to “compete with OTTs” – it’s simply a way to replicate & face-lift older 2G/3G circuit-based voicecalls. HD codecs aren’t new (they work on 3G too), and fast call setup has been available in the fixed PSTN since the 1980s.

    RCS and ViLTE have no obvious use-cases – there is no reason why a teenager would switch from SnapChat, nor a business user from Slack or Cisco Spark. The QoS angle is almost entirely irrelevant – a lot of use is over 3rd-party WiFi anyway, so app-developers build their apps to work around network glitches using various adaptive techniques. (I wrote a white paper recently for Amdocs, on why network-aware apps are often more important than app-aware networks).

    I’ll be interested to see Part 2, and I’m glad you recognised that “Voice” is much more than just phone calls, but there’s still nothing in VoLTE that suggests “comeback”. It’s just phonecalls v1.1 – a 130yr old service on a clunky 20yr old IMS platform.

    Dean Bubley

    • Konstantinos Stavropoulos
      Posted March 8, 2016 at 10:25 pm | Permalink

      Thank you for your comments, Dean.

      I invite you to read Part 2, which is now published. Note that my 2-part article was inspired by discussions with mobile network operators, industry experts and the Amdocs Network Solutions services team. These discussions confirmed the increased interest in solutions to launch/optimize VoLTE, an area I was first involved in (through a different role) back in 2012.

      Dr. Konstantinos Stavropoulos

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