As Small Cell Forum Chairman Alan Law produced their latest document release 5.1 today, focussed on RAN Virtualisation, he also revealed a wider revised remit along with an updated mission statement and tagline. Have the Forum lost their initial niche focus or simply adapted to the wider industry trends?
Looking back at achievements to date
The Forum believes there are over 11 million small cells deployed as of 31st March. The breakdown below highlights that over 95% are residential, while the higher capacity Urban ones contribute a disproportionately larger share of vendor revenues.
| Market Segment | Total Deployed |
| Residential | 10,600,000 |
| Enterprise | 450,000 |
| Urban | 16,500 |
| Rural and Remote | 20,000 |
The trend over recent years has been of growth, and their forecast showed a further positive picture. When I asked if the threat of VoWiFi (Wi-Fi Calling) was a concern, Alan said he thought it would have an impact on the residential sector but that the quality and control that a small cell provides would continue to provide a valued premium service.
Release 5.1: RAN Virtualisation
Today's publications were marked as a “point release” because the original expectation had been for a relatively concise study document. It’s expanded into 12 documents, with a wider scope including LAA, Wi-Fi Calling and even 5G. The primary focus of the release is still virtualisation, comprising five documents.
RAN virtualisation is really all about moving more of the functionality away from the edge (Radio heads) and into a centralised data centre or controller. The trade-off is that as more is centralised, then much higher bandwidth and lower latency backhaul is needed – as much as 10x more for the same throughput. The benefits are higher spectral efficiency and capacity.
The Forum has come up with an architecture split that puts most of the latency specific RF at the radio head, and centralises much of the intelligence. The split doesn’t have too great an impact on backhaul capacity which can still be carried over IP, albeit with tighter latency tolerances. The interface between the radio head and central controller is called nFAPI (network Function API). Expect to hear more about it soon. Documents are available to download on the forum documentation site.
As a runner up alternative, they also think that the PDCP architecture split may have some value and will continue to explore this option. Its main advantage would be to avoid any increase in backhaul overhead.
A new mission statement
Looking ahead, the Forum sees many innovations coming to the RAN and wants to be part of them. They’ve re-purposed themselves slightly with the following new mission statement and tagline.
Drive the wide scale adoption of Small Cells and accelerate the delivery of Integrated HetNets
“Solving the HetNet puzzle"
Aspects they’d like to cover include, but are not limited to: Macrocells, DAS, M2M, SON, Virtualisation, 5G, Carrier Wi-Fi, Wi-Fi Calling, LAA and LWA. I think that covers pretty much all the hot topics in mobile network radio architecture today and the next few years.
Their next major Release 6, in about 12 months, will address the wider scope of this HetNet evolution. The Forum would like to assist network operators evolve their radio networks “in the best and right way”, and sees its role as an educator and facilitator rather than as a standards body.
I’m sure there are many equipment vendors that would like to do that as well, so I hope this independent and educational approach will help the industry move in the right direction for all. We should also expect to see the Forum become more active in lobbying for change, rather than just publishing relevant documents.
Announced at the opening of this year's Small Cell World Summit in London, we'll be asking delegates what they think of this re-purposed mission. Look out for our detailed event report in due course.
