Telecoms.com periodically invites expert third parties to share their views on the industry’s most pressing issues. In this piece, Ingo Flomer, Director of Product Management at Cobham Wireless, discusses the RF challenges impacting the deployment of VoLTE services.

VoLTE has the potential to revolutionise voice services in the same way LTE has changed the market for mobile data services. However, there are still several barriers to the successful launch of next generation voice which must be overcome before operators will see a return on this large technological investment. One of the key issues is ensuring strong enough LTE signals are available where the majority of voice calls are made – indoors.

While VoLTE has the potential to deliver ultra-high quality voice and dramatically improve subscriber experience, its success wholly depends on the quality and capacity of the underlying LTE network – which has been shown to have some significant shortcomings. A pertinent problem is the large number of  indoor ‘notspots’ present in both urban and rural areas – which if left unaddressed could lead to an untimely demise for the incoming technology.

LTE signals are prone to the same limitations as previous generations of RF technology. Despite the protests of some operators, who argue LTE is more effective indoors than previous RF generations, construction materials old and new still significantly inhibit radio transmission and diminish service quality.

Furthermore, in dense urban environments the increasing number of smartphones and mass uptake of data-heavy services means a greater number of individuals are vying for a finite amount of capacity, causing a data crunch that ultimately makes maintaining a consistent and quality VoLTE call unlikely. This is likely to become even more of a problem as ‘connected’ items begin to enter the majority of homes.

More often than not, calls intended to run over LTE will be switched back to legacy GSM voice services, making any investment in VoLTE redundant and leaving operators unable to market next generation voice as a premium service.

Sending the right signals

To ensure indoor VoLTE signals remain stable, operators must ensure that the signal to noise ratio is sufficient to provide high throughput. The best way to achieve this is by using specific in-building coverage solutions such as Distributed Antenna Systems (DAS), which forward-thinking facilities managers and mobile network operators have been using for a number of years in locations requiring enhanced coverage provision, such as stadia and universities.

However, as demand for high-bandwidth applications has increased beyond basic data services, the requirements for coverage provision have extended to increasingly varied scenarios. As a modern construction containing thousands of connected devices, the managers of London’s Shard turned to DAS to satisfy corporate tenants that would be unwilling to accept poor access to mobile broadband. This trend is not only apparent in the construction of office buildings, but also in the residential sphere. Four-bar mobile coverage is now seen as a utility, which means construction companies and facilities managers must ensure that a lack of coverage does not influence the purchasing decision of prospective residents.

In enterprises such as shopping centres there is also a great need for coverage strong enough to support LTE – and with it VoLTE services – as customers that have to move outside or away from the venue in order to communicate will spend less time, and therefore spend less money, in the site. Despite the lack of coverage often being the result of building materials or geographic factors, subscribers will first place the blame on their mobile operator. With this in mind, carriers often partner with construction companies and facilities managers, as well as suitable vendors of coverage provision equipment, to increase customer satisfaction and avoid subscriber churn on mobile networks.

Wi-Fi offload and small cells are both options that can contribute to resolving the coverage issues at hand, but the advent of intelligent digital DAS systems has made providing the necessary capacity and consistency for seamless communication considerably easier and cheaper. Intelligent DAS allows venues with complementary requirements to share capacity allocated depending on each area’s needs throughout the day. A shopping centre, casino and sports stadium, for example, could install one coverage system as a joint venture and dynamically reallocate coverage depending on each location’s needs. During sporting events coverage will be allocated to the stadium, while in the evening it will be pushed to the casino and the shopping centre will benefit during daytime hours. All of these venues benefit from increased customer satisfaction while operators retain the favour of their subscribers.

As the demand for next generation voice and data continue to grow in tandem, operators are partnering with an increasing number of enterprises insisting on guaranteed provision. In the case of VoLTE, collaboration is the key to successful deployments and increased consumer uptake in addition to customer satisfaction.

Ingo is responsible for defining the product management strategy at Cobham Wireless. He has over 20 years’ experience in telecommunications infrastructure and is also an Advisory Board Member for several enterprises and research projects.