Making VoLTE work – Fast

Executive Summary

The explosion of mobile data services has given additional impetus to the need for inband voice and messaging services to become the norm. Using Mobile Data capable spectrum for 2G and 3G voice is increasingly seen as an inefficient use of valuable spectrum. From an operator’s perspective, Voice over LTE (VoLTE) is now an imperative for the efficient use of spectrum resources, in addition to the provision of high quality voice and fast call setup.

However, VoLTE is not a more efficient evolution of TDM Voice in the way that 3G was, it is an IP based technology that requires the application of IP skills to a Radio environment. Without a stable 4G Radio based IP-LAN, VoLTE will experience the same QoS issues that VoIP experiences on poor Enterprise IP-LAN’s. The traditional approach to cell planning will not work when delivering VoLTE. Making VoLTE work requires a company with deep knowledge of the Radio Access Network complemented by IP skills applied to the Radio and Core Network. Aspire Technology has the operational experience to be your partner in the transition from the traditional TDM voice world to the VoLTE world.



According to the GSA (Global mobile suppliers association) as of April 2016, 126 operators in 60 countries are investing in VoLTE (Voice over LTE/4G).

Of this, 55 operators from 34 countries have commercially launched VoLTE.

VoLTE brings a number of benefits to both end users and operators compared to 2G/ 3G networks.

For end users there is faster call setup, better voice quality and lower battery drain.

For operators there is:

  • Opportunity to use a single core network for voice and packet services which frees up valuable spectrum for LTE/4G data services
  • Higher revenue by using RCS multimedia services and
  • Enabling fully integrated Voice over Wi-Fi providing improved voice services in indoor locations.

Ultimately, moving voice off 2G/3G will accelerate the shutdown of legacy networks in favour of LTE and reducing overall OPEX costs.


VoLTE Deployment Challenges

VoLTE deployment has significant challenges beyond deploying an application of a 4G bearer. It is an end to end service with significant impacts to handsets and the Radio Access and Core networks.

A common misconception is that VoLTE deployment complexities are primarily related to the core network. Although IMS (IP Multimedia Subsystem) core networks can be demanding due to different vendor implementations, ensuring end to end interoperability will remain the key challenge. A stable and optimally configured the “Mobile IP-LAN”, built upon the 4G RAN is equally important in order to deliver high definition voice in LTE/4G.

Aspire’s experience from working with global operators on VoLTE is that the RAN is often overlooked when it comes to VoLTE service quality. We have seen through our work that over 60% of issues impacting VoLTE service quality have their root cause in the RAN.


These issues are mitigated through a number of activities including:

  • Activation and tuning of RAN features based on our experience and knowledge
  • RF physical optimisation to maximise LTE coverage, minimising mobility with legacy voice networks
  • RAN optimisation including access and mobility strategy and vendor parameter settings

It is only by overcoming these issues that VoLTE service quality will be better than legacy voice on 2G/3G networks.


The Aspire Approach

Aspire has worked globally supporting operators prepare to launch VoLTE services.

Our results speak for themselves:

  • 78% reduction in Dropped Call Rate
  • 88% reduction in Blocked Call Rate
  • Voice quality MOS (POLQA) average up from 3.75 to 3.95

These results are achieved through expert engineering services built up over decades working with many of the largest network operators and infrastructure vendors globally.

Our vendor agnostic approach to securing VoLTE service quality includes:

  • Supporting pre-launch cluster drive test and optimisation
  • Enabling VoLTE features and verifying KPI improvements
  • Analyse drive test data to identify dropped calls, failed calls, low MOS, CSFB and SRVCC (Single Radio Voice Call Continuity) failures in multi-vendor LTE, 3G and 2G networks
  • Identifying failure root cause and implementing recommendations and fixes
  • Network parameter audit and benchmarking
  • Performing end to end signalling message analysis for fault localisation and speech issue
  • Delivering VoLTE KPIs dashboard and quality assurance


Further Information on VoLTE

Click here to learn more about how Aspire can help you with your VoLTE launch.



Antonino Canale and Majda Putrih

Contact us to find out how we can improve your network