Ready for launch – the importance of validating VoLTE
At present, however, the failure of the industry to reach interoperability agreements is hampering the test processes at the core of successful deployments. Only by overcoming this inaction can operators ensure robust networks and the effective integration of widespread VoLTE services.
The demand for VoLTE is being driven by the rapid and widespread uptake of LTE services by mobile subscribers. As 4G networks proliferate and become capable of offering widespread communications, VoLTE has become the clear choice for next-generation voice services. While VoLTE has the potential to offer a new level of audio quality for consumers, it is rightly seen as one of the most difficult technical challenges mobile network operators will face during the next two years.
When you consider that subscribers demand consistency from their voice services more than any other mobile network service, the stakes for operators to deliver seamless and effective VoLTE communications could not be higher. VoLTE services must at least match legacy voice services in terms of quality and reliability to avoid subscriber churn. In fact, the technology should considerably exceed legacy 2G and 3G communications if operators are ever to portray VoLTE as a premium service – and realise the increased revenues that would result from this.
To guarantee their subscribers experience a superior service level, operators must test and validate VoLTE using complete application emulation, encompassing the full range of complexities within an intelligent modern network. This must include accurate prioritisation of traffic, given the range of high-bandwidth services being provided over the same data network, and the priority given by users to voice communication. In addition to ensuring traffic is correctly prioritised, operators must adopt the correct authentication protocols alongside developing robust handover technology to switch back to legacy technology. This must be done using complete scenario testing and call volume and regularity tests.
The methods currently in place to measure the quality of calls made over voice networks are inadequate when it comes to validating VoLTE performance at a macro-network level. Current techniques involve monitoring real-world calls at wide intervals, but this does not allow for the identification of instantaneous network issues to enable them to be addressed effectively, nor does it give network managers a robust understanding of end-to-end call quality. To accurately identify why problems occur, providers need to investigate what else was happening on the network at the time of the problem which may have interrupted the packet flow and led to an unsatisfactory calling experience. The range of technical metrics requiring examination and the scale required is extensive, but crucial, to the successful deployment of VoLTE.
It’s no surprise that two calls tested in isolation on the network would likely lead to excellent results, however it’s scaling-up that causes problems, especially when taken into account with the other high-bandwidth traffic which may strain the network at the same time. The testing process must therefore account for this, and should encompass a testbed that can scale to emulate hundreds, if not thousands, of calls taking place in tandem in real-world conditions.
Teething problems
A number of early adopters have already rolled out VoLTE to a number of their customers, who have discovered considerable issues when it comes to ensuring service and general network performance. Issues arising after the service launch can be extremely disruptive, lead to subscriber churn and potentially undermine the rollout (and therefore the investment) of the technology in the first place. It is imperative that operators validate these new voice networks before launch where possible, and that they do so in the correct conditions for the subscribers that will be making use of the service.
One of the key problems for the effective rollout of VoLTE is that while LTE protocols have been well standardised, the IMS (IP Multimedia Subsystem) that defines VoLTE is still relatively new and, as such, is undefined by industry bodies and equipment manufacturers. This brings about considerable interoperability and standardisation issues and, while some providers have already launched their own interpretations and configurations, these differ to those used and tested in labs. Failing to agree upon and enforce a consistent protocol will lead to consumer dissatisfaction, as they will not tolerate a lack of interoperability between what they will see as identical voice services. Beyond single vendors losing out on VoLTE, failure to agree on general industry-wide protocols could see the VoLTE launch timeline delayed as failed deployments deplete the appetite for further investment.
VoLTE deployment provides a wide range of issues which need to be addressed quickly and thoroughly to ensure the success of next-generation voice and the promised boost in usage and revenue. Interoperability will allow for consistent technology and consistent testing — without this the new technology is doomed to failure.
The author, Marko Falck is the Senior Product Manager at Cobham Wireless.
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