Not very long ago, using a mobile phone in your home or office was considered absolutely unacceptable on cost grounds, but as the cost of cellular calling has come down and the use of smartphones, tablet devices and laptops on the move has radically increased, it is now acceptable to communicate unwired, whatever the location.
That places significant pressure on cellular operators to ensure they can provide quality capacity indoors. It isn’t only operators that are involved in the in-building market but, almost without exception, they are involved in projects to at least some extent. After all, an in-building network needs to connect to the operator network at some point.
As mobile becomes used in these fixed locations – users typically make the bulk of their network consumption from either their home or their office and operators often garner up to 90% of their revenue from communications conducted within buildings – operators have a range of options to address the market need. The good news is that the need is relatively predictable and operators can invest in in-building technologies with good visibility into the business model.
‘There are a lot of public wireless providers and a lot of innovation around open access Wi-Fi,’ points out Steve Shaw, VP of corporate marketing at Kineto Wireless, a company that provides smartphone applications to establish secure connections over Wi-Fi. ‘The reality is that somewhere in the region of a half to two-thirds of communications in the home or the office are private networks.’
Operators are clearly aware of that. Vodafone has been offering its femotcell Sure Signal proposition for more than a year now and other providers have picocell and femtocell propositions either on the market or in the pipeline. However, those won’t be powerful enough for high footfall locations and, as Shaw points out, few users have reached their point of maximum bandwidth consumption yet. Powerful options are therefore needed depending on the site to be covered.
Håkan Samuelsson, CTO of Axell Wireless, explains the need: ‘Mobile operators need to provide cost-effective indoor coverage for consumers and to all of their business customers, whether an SME or a major enterprise,’ he says.
‘Operators are facing the complex challenge of providing high quality data coverage indoors to capitalise on the demand for mobile broadband and data services while ARPU is in decline. With some 80% of mobile phone traffic now originating from within buildings and the rapid growth of data applications, the need to have strong coverage levels for 3G and 4G services is greater than ever.’
The market is wide and Stephen Rayment, CTO of BelAir Networks sees many verticals relying on Wi-Fi. ‘When it comes to carrier-grade Wi-Fi we see specific interest at organisations that have a high ratio of customers or employees on site,’ he says. ‘This includes specific verticals such as education, retail, healthcare, hospitality, entertainment and sports venues, convention centres, transportation, public libraries and even certain government buildings.’
Bill Agg, director of customer services at Zinwave agrees, and says his company has provided solutions in situations as diverse as a nuclear power plant and a sports stadium.
‘A building owner can put in any of the services they want,’ he adds.
‘We’ve talked about the ability to tag children in large shopping centres. There’s no limit.’
However, who runs the in-building network can shift from market to market, he says: ‘In the UK it’s driven by operators, in Europe by operators and building owners and in the Far East it tends to be the building owners – it can be anyone.’
Samuelsson sees only the operators as having a significant impact. ‘The operator will oversee the in-building network,’ he says. ‘One of the advantages of deploying multi-band repeaters that can be remotely configured is that the installation and ongoing maintenance of the equipment will cause minimal disruption to the site.’
That’s a critical point for all in-building deployments. Building owners don’t want hundreds of metres of co-axial cable installed linking each repeater and replicated for each technology supported. In addition, they want as few repeaters installed in their premises as possible so multi-band equipment is becoming increasingly attractive, as is more powerful equipment that has both a greater range and needs to be supported by thinner co-axial cable.
That’s an issue being addressed by Ruckus Wireless, a company that uses technology designed for the domestic IPTV delivery market to improve coverage from antennae.
DAS and SDR systems
‘Everybody in the indoor market uses omnidirectional antennae,’ says Jim Calderbank, the company’s director of EMEA enterprise sales. ‘They produce energy in all directions equally, so we’ve developed technology that reflects that for wall-mounted applications. Think of it as a lightbulb. When you put a reflector behind it, it becomes a searchlight.’
For enterprise-grade applications there are many technologies available, but the concept and design is commonly called DAS (Distributed Antenna System). DAS propagate a signal throughout a building or constrained location and can run from femto and picocells through to larger scale equipment for high demand sites.
Samuelsson explains Axell Wireless’ offering: ‘We provide digital multi-band repeaters, which employ software defined radio (SDR),’ he says. ‘The multi-band repeaters are able to simultaneously handle 2G, 3G and 4G LTE network connections. RF engineers can use remote monitoring to take account of standards variations, spectrum availability and any other operator requirements.’
Only a few vendors have fully active systems available. ‘The disadvantage of passive or hybrid systems is that they are all to some extent or another band-specific,’ explains Agg. ‘They take the service and demodulate it down to a band and remodulate it at the other end so the system is very specific to frequencies and services and the provider has to put in more and more infrastructure to support it.’
Samuelsson doesn’t see many alternatives to DAS. ‘So what are the other options?’ he asks. ‘Picocells are adequate for providing coverage for wireless hotspots, but they are also capacity limited and prone to overload if too many users want access at the same time. Wi-Fi and femtocell offload have proved to be effective for residential application, but neither of those solutions scale for major in-building implementations, either in terms of the number of concurrent users that can be supported or in the desired quality of service parameters.
‘One approach would be to deploy dedicated LTE base stations, but installing new equipment can be a costly and time consuming process, even for small scale indoor deployments when backhaul costs are added.’