At the Mobile World Congress, Cellnex unveiled the projects being developed inside the tower designed by Norman Foster, now its most strategic hub. Small cells will bring broadband to crowded areas by using buildings, streetlights, bus stops and even road signage
Enabling the widespread deployment of 5G across urban environments: this is the project being pursued by tower company Cellnex Telecom, which unveiled its ongoing initiatives during the Mobile World Congress in Barcelona. And Barcelona itself is the city where this new “worksite” is now active.
At the heart of the operation is the Collserola Tower, a true innovation hub. Inaugurated for the 1992 Barcelona Olympic Games and designed by architect Sir Norman Foster — in collaboration with engineering firms Ove Arup and Cast — the tower is not only an architectural icon. Standing 288 metres high and located at the city’s highest panoramic point, the Mirador, 560 metres above sea level, it offers a viewing radius of 70 kilometres. It is also the nerve centre of Cellnex’s operations.
The tower is owned by Sociedad Anónima Torre de Collserola, whose shareholders include Cellnex with 41.75%, Spanish telecommunications company Telefónica with 30.40%, the Generalitat de Catalunya with 22.85%, and Àrea Metropolitana de Barcelona with 5%.
Originally built as Spain’s main centre for large-scale radio communications and television and radio broadcasting, the tower today serves as Cellnex’s advanced innovation hub. It hosts the company’s Global Network Operations Centre, known as the NOC, and acts as a test bed for 5G, IoT and quantum technologies.
“The challenge of 5G lies between coverage and capacity: while macro towers provide broad coverage, urban environments require data transmission capacity delivered drop by drop,” explains Oscar Pallarols, Chief Commercial Officer at Cellnex. “This is achieved through small cells positioned across the surfaces of the city, from building façades to public transport stops, from streetlights to signage.”
In practice, the antennas are integrated directly into urban furniture. Designed to blend into existing elements, they can manage data traffic in very crowded areas — squares, stadiums and historic centres — where the signal from macro cells struggles to penetrate or becomes saturated. They also support smart city services.
But the challenge is complex. “At present, mobile network operators own and manage their own small cells, which makes the total cost prohibitive for large-scale deployment.”
It is in this context that Cellnex has chosen to propose a completely different model. Acting as a “neutral host”, the company provides telecommunications operators with all the infrastructure needed to enable these projects: from sites and fibre to power supply and the necessary hardware. In essence, it is an infrastructure-sharing model in which several operators can access sites without having to build them from scratch. Each operator transmits on its own frequency while using the same physical unit.
A pilot project is currently operational in London and is managed entirely from the NOC inside the Collserola Tower. In Italy, Milan is home to one of Cellnex’s main projects in the field of infrastructure “densification”. Following an agreement with the municipality, the company implemented a “Multi-Operator Outdoor DAS” system at street level, using existing urban furniture such as streetlights, traffic lights and buildings, with all mobile operators on board. In some cases, radio units have also been installed in the metro, minimising the visual impact of equipment across the city.
“Cost-sharing through this neutral host model is the real driver needed for large-scale urban small cell deployments,” Pallarols points out.
There is also the issue of environmental sustainability. Cellnex aims to transform telecommunications sites from energy “consumers” into intelligent nodes capable of helping balance the electricity grid.
“Infrastructure must be resilient to extreme events and instability in the energy network. In addition to ensuring operational continuity — up to five days without grid power — we use the batteries installed at our sites in aggregated form. This capacity is offered to energy operators to stabilise the national grid during peaks in demand, absorbing or releasing energy as required.”
In effect, Cellnex aims to position itself as a genuine energy player, creating a new business model that uses existing infrastructure to contribute to the stability and efficiency of the national energy system.
Cover image: © Torre de Collserola
