It’s was an Herculean task. Build a London-wide small cells network in six months, in time for the Olympics and the millions of tourists flocking to the UK capital.
Robert Joyce, chief radio engineer at O2 in the UK, recounted the challenges of deploying small cells on a large scale in a metropolitan environment. The resulting network includes of the densest deployments of indoor small cells, anywhere in the world (more of that later).
According to Joyce, traffic growth is a city like London is uneven. In some locations it could be x50 which makes it hard to plan for and scale for future demand.
To meet this demand for mobile data, O2 has a strategy of using both Wi-Fi and small cells. In 2009 it started to build out its own 14,000 Wi-Fi access point network. The next step is to seamlessly combine the two technologies n an open-access format. London would be the ideal experiment to see if small cells to could scale to public service.

The London Boroughs of Westminster and Kensington & Chelsea were auctioning off their street furniture (i.e. lampposts) so 02 bought the rights to hang metrocells from them. Due to stipulations from the councils, O2 had to deploy within 6 months, which would coincide with the Olympics in July 2012.
You may have thought that the councils would be doing their best to help this happen. But O2 still had to compete 400 individual planning applications in order to use the street furniture as metrocells (and they still had to stick to the 6 month time frame).
With permissions gained, O2 deployed combined Wi-Fi (from Ruckus) and femtocells (from Alcatel-Lucent) in public spaces. For instance, In Exhibition Road in Kensington, which will be a focal point for many of the Olympic activities, O2 deployed 9 metrocells. Combined, they deliver 1gbps per square kilometre. “This is where we think we will need to be by 2015 to meet demand,” said Joyce.
Backhaul was no simple task. They couldn’t sink new fibre to each metrocell, so they had to use a combination of fibre/ethernet that they provisioned from fixed line operators, line-of-sight radio to macrocells, and a mesh network between the small cells access points.
The boxes are non-intrusive, you can hardly notice them 20 feet up. Certainly much smaller than a traditional macrocell.
A similarly dense metro network was deployed in Trafalgar Square but with even more complex backhaul.
Perhaps most interesting is a major residential development in East London, where there are 1200 femtocells being deployed including 65 in one block alone. “Because of the aluminium shielding used in the construction of the apartments, the macro network could not penetrate it. We needed indoor cells, ” said Joyce.
He believes it is the largest, densest deployment of metrocells anywhere in the world. Do you know of any denser small cells networks?
By Stewart Baines, guest writer, from Futurity Media

