Small Cells have been a talking point for many years now. There was a time some years back when they seemed to be the next hot topic, the Small Cells forum was born and everyone was talking about small cell solutions. I often wonder what makes small, small and whether small will become big!

What do I mean by this? Well when small cells became the hot topic, MNOs were actually already doing small stuff – small footprint cells from a radio coverage perspective using small footprint equipment, small structures (such as mock lighting columns) and smaller capex budgets than what are required for a big macrocell – in fact they were rolling out microcells. Was this the birth of the small cell? Microcells were (from a classical radio coverage perspective) supposed to be a lower level of coverage, below the surrounding building clutter and hence providing street level coverage over a more limited area that a macrocell. Some MNOs in the UK found a loophole in the requirement for paying rent on highways land and hence a proliferation of mock lighting columns happened. I recall being part of the design team who created the whole “Lamp post site” concept with a major UK MNO and was somewhat surprised as to how over time many MNOs morphed these designs into ever larger structures and equipment cabinets and the term “Mini Macro” started being bandied about. It felt like the microcell had an identity crisis; it had been on steroids and grown bigger than intended! Some of this was driven by the economics of the solution, no ground rent, smaller capex than a full blown macro and the ability to push the design to achieve larger coverage footprints meant the MNOS wanted to squeeze maximum bang for buck from the designs and the associated capex budget.

Then came the Small Cells fervour and a lot of pundits thought that MNOs would be deploying Small Cells en-masse. It was easy to see why – many areas had been saturated with macrocells, some microcells had also been deployed and with increasing demands for higher bandwidth services and the associated capacity required to serve them it seemed logical that another layer of cells would appear below the macro and micro ones. “Ah a picocell” I hear all you die hard radio planners say – well yes, this classic layered vision of the radio network had been around for a while and it was expected that picos would follow micros in the layered rollout vision. In fact I recall going to Finalnd to see a new product from Nokia (before the NSN and the new Nokia days) that was specifically built to serve the pico market it was called “Insite” and I thought it was rather a good concept unfortunately despite the impressive investment in a mass production facility in Finland the product had limited functionality and as anyone who has worked in a radio engineering function will know, us engineers like our functionality. Anything below the required GSM/GPRS/EDGE/UMTS/HSPA/HSPA+/LTE/LTE-A functionality is seen as a little undesirable by the engineering fraternity. The Insite was a GSM only non-EDGE capable base station at a time when data was started to become a reality on mobile networks. Due to lack of demand the rather cute A4 sized Insite was put to bed, never to be woken again.

Now I’m not having a good at Nokia here, the other vendors were also considering or doing similar things but there is a theme emerging regarding what MNOs demand from a product and how that impacts the cost of providing a picocell or small cell that meets their requirements.

Why does this matter? Well picocells have competition, there’s a another guy on the block whose been around for a while, somewhat seen as a sideshow by the MNOs for some time but becoming an increasingly serious contender for the small cell crown – Mr Wi-Fi Access Point, already rolled out en-masse and offering data services to cellular customers all over the world.

“It’s not a small cell” I hear the dissenters shout – “it’s not cellular, not part of the cellular network layers, an outsider incapable of mobility, data only, out of step with radio network equipment functionality, can’t be monitored as part of our network management systems…….” Well I would agree based on those arguments but based on the need to provide a small footprint of coverage to a dedicated location allowing customers to access data services from their cellular devices I would disagree – Wi-Fi access points are already out there providing “Small cell” type coverage.

I went to a base station themed conference in Bristol UK in 2012 and there was still a lot of talk about small cells, in addition there was a lot of discussion about “HetNets” – Heterogeneous Networks with lots of different spectrum bands, technologies and cellular layers needing to be glued together seamlessly to offer customers coverage, capacity and functionality where they needed it. Nothing wrong with that I say, but the small cell layer had still not emerged in the real world as seen by the visions of the presenters. I didn’t see a lot of people presenting on cellular small cell rollout success stories. What I did see was O2 presenting the success of their Wi-Fi network rollout in London particularly around Oxford St, Exhibition Rd and Trafalgar Sq. plus Virgin Media talking about their London Underground Wi-Fi deployment. Don’t get me wrong full blown cellular technology small cells were also being discussed and presented but very much in the trial phases.

OK this is a few years out of date but in the same year some commentators were stating that Small cells would account for 88% of all mobile base stations by 2016. I’m not convinced, even now – I’m still not seeing mass rollout headlines for small cells of the cellular kind. My ex colleagues in the MNO world do not appear to be planning large pro-active small cell layers across all their most populated areas of coverage. “What about AT&T?” I hear you shout “they were expected to deploy 40,000 small cells by 2015” – I haven’t seen mass publicity about progress on this initiative, it’s not easy to find.
Meanwhile that lean and mean Mr Wi-Fi Access Point continues to stride on emerging everywhere and anywhere – even my local Sainsburys is offering free Wi-Fi which makes it convenient for the budget conscious shopper when checking the price of a toaster at Argos compared to their special promotion………..but I digress.

So what does this mean anything, nothing or something? Well I haven’t got a downer on full blown cellular small cells there is indeed a place for them but it feels like the small cell is suffering a bit like our Microcell on steroids – it has an identity crisis. Is it cellular or Wi-Fi or both and which identity should it adapt to become big?
This is a complex issue (as all techies like to say) there may still be a wave of pro-active small cell deployments by the MNOs especially now the likes of 2600MHz spectrum is in their hands – an ideal spectrum band for small cell / hot spot coverage deployment. However practical challenges remain.

First and foremost location – as any homebuyer knows, location is key; the same applies to a small cell deployment. The fact is if you are using your small cell to soak up demand driven by your consumers then in today’s world of high bandwidth consumption they are generally located in a specific area sat streaming the latest episode of Game of Thrones or catching up on The Great British Bake Off in HD. OK so just put the small cell where they are then: simple to say but less so to do. A lot of this consumption is in cities in areas where there also happens to be a lot of retail and service industry presence – big brand names in desirable looking spaces or trendy boutiques in fashionable streets. So what? Well if you want shop front space in Bond Street expect to pay in excess of £900 per square foot – very nice for the landlord. Cue Mr MNO knocking on landlords door asking if they can come and drill the walls and mount base station, antennas and cables, disrupt the retail space, put something ugly on the face of the building (with a H&S warning about radiation on it) and pay a pitiful amount for rent. Oh you also need the local authority to approve you destroying the look of that nice regency façade with a bit of telecom’s kit. Guess what – you can’t get the Small Cell where you need it, you might be able to find another property a bit further away but then you are not quite covering the hot spot you need to.

In addition to being able to get the small cell exactly where you want it, you then need to connect it to your mobile network. You’re in a high demand area so you need a good sized backhaul solution, no line of site for a microwave transmission solution due to the environment so it’s a fixed line solution with similar pricing to a full blown macrocell leased line. OK I could try and use a non-line of site microwave solution but again – I get the feeling these solutions are limited in number in the real world.

Then there is the cost of the equipment. The engineering functions in the MNOs want a fully standards compliant small cell – a big stamp of 3GPP compliance and all the mobility and radio functionality expected. Fair enough that is their job but compare that to the required functionality for a Wi-Fi Access point and the associated cost and you have another headache to contend with – how do you justify the cost of the equipment.
So as an MNO you are struggling to locate your (cellular) small cell so you may not cover the area you need to, the transmission cost is relatively high and your equipment price point is way off compared to a WiFi Access Point – Is this good bang for buck for your capex?

Meanwhile the tenant in the retail space has brought some Wi-Fi access points, plugged them into the internet and started offering service to their clients.
Maybe I’m sounding like a fully paid up member of the Wi-Fi Alliance but frankly I have no bias either way. I accept that there are other variants of small cells that are a bit easier to deploy such as Femtoc ells that can be plugged into the internet for connectivity and look very much like a Wi-Fi Access Point but I guess I am trying to make a point about mass small cell deployment. The reality is that there are many challenges to small cell deployment of the traditional cellular kind as articulated above and whilst the MNOs have been struggling to justify a proactive small cell rollout, leaner and meaner Mr Wi-Fi has sneaked round the back and got all the customers, hell some landlords are even making sure they get Wi-Fi to ensure users of their premises get what they want – coverage wherever they are.

Whilst the MNO engineers continue to demand functionality from their small cell providers that is absent from Wi-Fi pushing the price point and complexity up, their network end users are happily using a much lower spec, lower price point, less functional solution because it gives them the hot spot data coverage they need. Allied to that the next generation of Wi-Fi access points are coming supporting radio functionalities such as Multi-User MiMO giving multiple users much higher data rates thus meaning Wi-Fi will continue to be the sole source of data coverage in many areas as consumer demand for bandwidth increases. Add to that Wi-Fi calling capability and suddenly you have a Wi-Fi solution that directly competes with your cellular small cell. Oh and you don’t get stung with data roaming charges when you use Wi-Fi solutions abroad with the many Free Wi-Fi services on offer.

One other issue that also contributes to the consideration of whether mass small cell rollout will become a reality is the very prudent practice of MNOs sweating their assets to the maximum. Having spent a fortune rolling out a macrocell network you want to make sure you get every available improvement possible from this network before you start rolling out another one. With the advent of lower band spectrum for LTE and techniques such as Carrier Aggregation (CA) offering more data throughput and capacity capability one could argue that MNOs will continue to try and cover those urban areas both indoors and outdoors with their existing macrocell base. The superior in-building penetration of low band spectrum and the improved data capabilities of CA could stave off the need for small cells just a while longer. Remember that MNOs are already companies with a high operational gearing and the addition of many hundreds of small cells just makes their operational challenges and cost base look even more scary than today – a time when MNOs are seeking to reduce site Opex costs through network sharing, not add to them with another major rollout!

So what’s the answer to my question – will small cells become big? I personally believe that from a Wi-Fi perspective they already are and will continue to get bigger but from a full blown cellular solution perspective there is still some way to go. If we believe the forecasts for data use and the need for very high bandwidth and ultra-low latency services there is no doubt many areas will need improved quality of coverage and capacity and it may be that the only way to achieve this and fully optimise it is with more, smaller cells (of the cellular variety!) connected to fibre backhaul and located closer to the end user.
There will always be practical challenges to deployment of any technology but I think the MNO and vendor community needs to consider what they think the end user needs and what end users are actually using as a solution today. Maybe a marriage of Wi-Fi and cellular is required with a fully open and functional relationship to really make MNOs end users and the Wi-Fi community benefit from the future of small cells. I don’t mean Cellular and Wi-Fi technologies sat together in one box either I mean a fully interoperable Wi-Fi/Cellular networking solution.

There are hints that 5G will deliver this kind of Multi Radio Access Technology, multi-layered interworking across licensed and un-licensed spectrum and vendors continue to talk about the need for ultra-dense networks with many small cells to enable users to get the throughput and latency required for next generation services.

However all this is just theory if you can’t get over the deployment practicalities and constraints and your cellular small cell solution price point. Much as the techies would love to roll-out masses of small cells, the truth is MNOs have limited capex and will continue to only do what is essential to keep up with the market; any mass small cell rollout programme will need the CFOs sign off, in no way an easy task in the current financial environment….