Macro, metro, micro or just plain small – capacity not coverage is the question

Operators across the world are turning to small cells to address their capacity issues. It’s clear that increased spectrum alone won’t be enough to meet the needs of data hungry users, writes George Malim

Macro, metro, micro or just plain small – capacity not coverage is the question

AT&T has committed to rolling out small cells across the US and European operators and are at an advanced stage of trialling the technology. However, they are not a universal panacea and will be deployed in conjunction with macrocells, distributed antenna systems (DAS) and Wi-Fi.

As a part of the technical solution to the capacity crunch, small cells won’t just be deployed to enable outdoor coverage - they will also be deployed to meet the needs of enterprises in their buildings and on their sites.

‘Compared to 3G, LTE service is focused on data,’ says Kim Chang-Young, senior manager of the Access Network Lab at South Korean mobile operator SK Telecom. ‘Therefore, to enhance network capacity, we expect to see more increases in enterprise small cell deployments rather than home-type small cells, which are often used for expanding network coverage. 

Integration issues

‘However, as enterprise small cells need to constantly interwork with macro base stations, if the macrocells and small cells are supplied by different vendors, it is crucial that we get help from the major vendor to address the [integration] issue with macrocells. The issue of standardisation on
the interworking between macrocells and small cells will
also act as an important factor in the growth of the related industries,’ says Kim Chang-Young.

Steve Hratko, director of service provider marketing at Ruckus Wireless, says that in the past indoor coverage has been provided either by coverage bouncing down the street from the nearest macro cell or DAS. ‘Both systems work quite well,’ he acknowledges, ‘but what they don’t do is provide a lot of capacity. We’re starting to see a desire to put more small cells in when it comes to data – enterprises always need more.’

Even so, a lot of capacity can be provided from the street using small cells. ‘As far as the whole industry is concerned, the solutions will be heterogeneous,’ says Kevin Baughan, director of wireless at Virgin Media Business. 

‘There will be small cells in buildings, metro cells in the street as well as macrocells. Obviously you can deploy small cells in offices but it will be interesting to see if those gain [acceptance] over DAS over time. We see small cells both inside and outside offices,’ says Baughan.

He adds that Virgin Media Business has had good results providing in-building capacity during trials using 2.6Ghz spectrum from small cells in the street. ‘Obviously, there will be buildings that, due to their construction or orientation, need DAS or something inside, but we’re very pleased with the level of building penetration we can achieve from the street.’

Even though approaches to small cell deployment are maturing and it is understood that this isn’t an either or scenario, many methods will be used to deliver capacity, the industry is working to make deployment easier and the different technologies interwork effectively.

‘Wi-Fi is very clean in terms of deployment because building or venue owners will put it in themselves,’ says Hratko. ‘Small cells are very different and operators will be asked to pay to install them.’

Greater capacity

Peter Jennings, the CTO of MLL Telecom, explains how varied the range of capacity options is becoming. ‘Macro cells are being used to give large area coverage – the recent spectrum auctions of
the sub 1GHz frequencies have shown how important ubiquitous coverage is,’ he says. 

‘Small cells are now being seen as a lower cost method for providing greater capacity where it is really needed. For an enterprise and in-vehicle coverage deployment, the mobile operator can use the macro cells to provide outdoor coverage. 

‘However, for detailed in-building coverage and greater capacity, the femto or small cell provides an excellent counterpart,’ adds Jennings. ‘It is no longer the case of one solution fits all, but with the similarity of coverage area, the mobile operators need more innovative methods of growing their revenue and business.’

Operators themselves just want the capacity – they care that it’s reliable, not how it is delivered. ‘For O2, it’s all about us providing customers with fast and reliable connectivity where they need it,’ says Derek McManus, chief operating officer for Telefónica UK. 

‘Our vision is for Wi-Fi to be simply another access layer to our mobile core. Customers don’t really care about the underlying technology; they care about getting connected, fast and reliably. The introduction of small cells helps us to support these requirements and completely complements our mobile strategy by letting us push capacity closer to users in locations where it makes the most sense.’

Others also see the value of Wi-Fi. ‘Most enterprise small cells are deployed in the same locations as Wi-Fi access points,’ explains Kim Chang-Young. ‘Wi-Fi is also a necessary solution – along with small cells – as it also offloads data from macrocells. Thus, by deploying those two systems together in a merged form, we can save cost – both capex and opex – and efforts for maintenance and management. Wi-Fi and small cells are not mutually competitive but complementary to each other.’

Baughan says that while the technologies are coming closer together, the business cases for each continue to diverge. ‘Wi-Fi is a great example of a small cell - we deployed it like a small cell architecture when we deployed Wi-Fi in the London Underground, but the big dividing factor is that one is a licenced technology and the other is not,’ he says. ‘The characteristics of Wi-Fi vary too widely for us to make it a strategic platform. We don’t think it’s strong enough to be something you could charge a monthly subscription to.’

Complementary tech

Others also see the technologies becoming complementary. David Nowicki, the chief marketing officer at Devicescape, a company that curates and automates access to amenity Wi-Fi at more than 100 million hotspots across the world, points out that the pressures operators face mean utilising Wi-Fi is an obvious way to mitigate capacity shortages. 

‘In a city like San Francisco, for example, there are around 100 [macrocell] base stations and 100 small cells per operator – one million users might be supported by 200 cells – but we can offer 27,000 hotspots across the city,’ he says. ‘That changes the way operators look at capacity – particularly inside buildings. Wi-Fi ends up being complementary.’

Hratko adds that he’s convinced the two technologies belong together. ‘We’ll see a lot of deployments and some will see [small cells and Wi-Fi] integrated at the circuit board level.’

Nitin Bhas, senior analyst at Juniper Research, sees operators deploying integrated Wi-Fi and small cells. The challenge is site acquisition, so it makes sense to maximize the potential offered by each site by installing multi-functional equipment.

‘There is no substitute for the capacity problem other than making cells smaller in order to have more capacity in a specific geographic area,’ he says. ‘Operators are and will make use of more integrated units of Wi-Fi and small cells. In the present environment it is most effective to use the cellular technology to handle the voice providing a transparency between being outdoors or indoors and being in a small cell or macrocell coverage area that no other solution could compare with at this point of time.’

Written by Wireless magazine
Wireless magazine

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