In-building cellular coverage has gone from a nice-to-have to a must-have. This trend was recently illustrated by PWC’s decision to ditch its landlines for the bulk of its employees with the goal of boosting their efficiency. Similarly, imagine two hotels – one where its guests can easily make phone calls and use their smartphones to their hearts’ content, and one where it’s impossible to get a decent signal; which of the two is likely to find it easier to fill its rooms?
Indeed, David Orloff, chair of the Small Cell Forum, says a study has shown that hotels can charge more per square foot when they have mobile connectivity throughout their premises. He also says (with the perspective of someone based in the US) that hospitals are heading in the same direction: “Customers of the hospital will go and be more comfortable choosing a specific healthcare provider if while they’re there they have mobility services. Even doctors are starting to [push for indoor connectivity] because they are interested in having access to procedures as they move throughout the hospital.”
Mick Goulding, head of sales and business development at Vilicom (a systems integrator), runs through the key considerations for any in-building wireless deployment: building size, the construction materials used (walls in modern buildings can reduce signal by 25-30dB), footfall (the key driver of capacity and coverage requirements), the possible use of enterprise applications on devices, whether or not the company is looking to use mobile phones as a complete replacement for landlines, and the budget available.
He explains that small cells are a natural fit for mid-sized enterprises, which he personally defines as a business that takes up one to four floors of an office building, where cost-efficiency is crucial but the footfall doesn’t resemble that of a shopping centre or football stadium. “A small cell system can fit very well on top of their existing infrastructure where it is cost-effective and the speed of deployment can be seen more readily and more quickly than an active DAS solution.”
There is more to small cells than just providing cellular coverage and capacity. The ability to dial down their signal strength and be situated wherever companies need the extra spatial resolution allows them to deliver location-based services (to an accuracy of around three metres) without the need for an extra wireless network, such as Bluetooth. According to the Small Cell Forum, these can be used to alert businesses to the presence of frequent customers and push personalised welcomes or promotions to their smartphones as they enter or leave their premises, with a view to increasing loyalty or the user experience. As discussed in my piece on wireless comms for retailers – ‘A helping hand’ (December 2017) – small cells can also help generate a wealth of data on customer behaviour and preferences, which can be used to tweak store layout and display designs.
Finally, with the growing use of cellular technologies for IoT, such as NB-IoT and LTE-M, location services can also be used to track the location of indoor assets – in a hospital environment allowing staff to know where expensive medical equipment is and make more efficient use of it.
Given small cells’ benefits, why aren’t they more commonplace? Marko Babovic, head of product line street and indoor at Ericsson, highlights the dominance of mobile network operators (MNOs) in the licensed cellular space, while at the same time, “it’s not very clear that MNOs see these [enterprise customers] as their main target. Most MNOs are still thinking about small cells (in this case, mostly indoor small cells) as a way to improve their networks, not necessarily to reach out for a new market for enterprise small cells.”
“The expectation that MNOs will pay to deploy systems for your enterprise has had to change,” adds Goulding. “Deploying indoor networks has become the [domain] of the enterprise sector going forward to meet [its] requirements, [which] have grown considerably, and the MNOs will not continue to be able to fund all of the investments in indoor environments that enterprises actually require.”
Babovic says another issue that has affected the growth of the small cells market is that the in-building cellular ecosystem of vendors, systems integrators and building owners has been used to relying on distributed antenna systems (DAS), “which have been working very well”, so it will take time for them to embrace small cells. One challenge in this regard is that the ease and speed at which small cells can be installed and deployed creates a headache for systems integrators, because the amount of work hours required to deploy in-building coverage with small cells is much lower than for DAS, affecting their margins and requiring them to adapt accordingly.
One key consideration highlighted by Orloff is whether the end-users require coverage from multiple operators, potentially via a neutral host solution. This hinges on whether the enterprise has any control over which MNO(s) their employees are using. Naturally, in the hospitality sector, the emphasis is on providing guests with seamless connectivity, which necessitates a multi-operator approach.
Turning to budgets, “it’s very clear that the most cost-effective time for getting a building ready for wireless capability is when you’re building the building; the next most cost-effective time is when you are retrofitting a building; but there’s still quite a number of options that are available for even steady state buildings for getting them ready for wireless mobility,” says Orloff.
It can be a temptation to try to save money by opting for cheap passive components,
but Michele Martoccia, market manager for cell sites at Huber+Suhner, warns that this can lead to high levels of passive intermodulation, which in turn degrade the overall system’s performance and “cause huge problems”.
Cost doesn’t have to mean capital expenditure – the industry is starting to experiment with alternative business models, such as Ericsson’s Small Cell as a Service.
Goulding says Vilicom uses a design process that is “based on a very detailed assessment of the customer’s requirements and the scope of the system that’s to be deployed to ensure that those requirements are properly met. It’s also to ensure that there is a level of future-proofing that is built into the network to accommodate for further advances in technology and further requirements that a customer may have that develop over time.”
Babovic adds that considerations around future-proofing have taken on fresh importance given the impending arrival of 5G and the need to avoid the cost and disruption caused by replacing everything previously installed for a worst-case scenario.
He says “one large airport that I have been contacting has been asking for a solution that is 5G-compatible” and highlights the fact that from a hardware perspective, Ericsson engineered the radio system that it launched in 2015 to be 5G-ready.
Martoccia highlights the need for small cell antennas to support the 5G candidate bands and provide at least 4 x 4 MIMO, given the data capacity it provides, and the backhaul to support it.
Goulding explains that even though a small cell network will act as a very small part of one or more MNO network, it still “has to be designed and deployed to fit in with that network. It can’t interfere with it, or in any way affect its performance.” He explains that ensuring this is the case is the role of systems integrators, and that while an enterprise would be starting from scratch if it tried to handle the negotiations with MNOs for a small cell deployment, “a professional services company has the relationships with MNOs and equipment providers, along with the experience in deploying these systems to enable a very big head-start”.
Goulding adds that Vilicom is working on multi-operator small-cell-fed DAS deployments, which he says “bridge the gap between what could be an expensive active DAS solution versus a single-operator-only small cell solution”.
Huber+Suhner’s Martoccia says that while small cell technology is being mainly driven by the large telecom infrastructure OEMs, there are many more vendors that have good small cell products and other in-building connectivity solutions.
“As both technologies have evolved, the characteristics of small cells and DAS have continued to blur,” adds Orloff. “Today, deployments of new generations of powerful small cells are significantly outnumbering DAS, but that’s not to say there is not potential for the two to coexist harmoniously. Rather, the focus has to be on how the mix of small cells and DAS, with each correctly deployed in their appropriate settings, will provide the huge increases of cost-effective bandwidth required to facilitate new networks such as 5G.”
Before I sign off, it’s worth noting that the Small Cell Forum has an enterprise advisory council that includes companies such as General Motors and Marriott Hotels. Orloff says this allows the forum to have an ongoing dialogue with them to allow them to get a better understanding of small cell solutions and allow the forum to better understand their challenges and requirements. Orloff adds that if other enterprises wish to participate, “we’d love to have them. If they want to participate, they can reach out to us.”
Coverage without capacity
Given that Ofcom has recently relaxed some of the restrictions around the use of off-air repeaters, it’s worth devoting a bit of time to examining how they differ from small cells. Goulding explains that “off-air repeaters take the signal from an MNO’s macro-network and repeat it inside [a building]”. A potential issue here is that unlike small cells they enable more users to use the same network without adding any additional capacity – perhaps not the best approach given the data-hungry nature of many smartphone users.
“In dense urban locations where capacity is at a premium, its reuse is almost frowned upon by the MNOs,” Goulding adds. “Repeaters have a very restricted role to play in those environments. Off-air repeaters probably don’t fit into the mid-sized enterprise environment.”
Babovic adds that the perfect scenario for an off-air repeater is bringing coverage into an area where there is absolutely no pre-existing coverage (such as a basement), giving you “a perfect demarcation point” between the coverage it provides and that of the macro-cell it is extending.
Above right: the use of off-air repeaters in dense urban areas is ‘almost frowned upon by the MNOs’
