The mobile networks industry is well aware that the coming years will see a remarkable rise in global data traffic. Indeed, it has been estimated that traffic will increase sevenfold between 2016 and 2021, while the year 2016 alone saw it increase by 63%. Providers have thus far been able to keep up with the demand by incorporating new technologies into their networks. Taking its place at the forefront of these innovations is the evolved small cell. While it has been used for over a decade, its full potential is just starting to unfold.
Small Cells: A Definition
Small cells refer to all types of small, low-powered radio access nodes that are controlled by a single operator and have a range varying between 20 meters and 2 kilometers. This definition remains quite vague, which is why the concept is better illustrated by a description of its function. Essentially, small cells are tools for network densification: they augment a cellular network’s capacity by moving traffic off the macro load. In other words, they are used to complement macrocell tower networks. When in range, a small cell is automatically detected by a mobile device and is used in priority. The short range makes for quicker and more efficient services.
While their use is only now on the rise, small cells have been on carriers’ radars awhile. They have been used for over a decade, mostly within residential and business settings. These devices, typically installed indoors and crudely resembling a WI-Fi router, appealed to users by increasing capacity and providing an overall better user experience. Enterprises with a need for highly reliable coverage could make their units available to multiple users.
Some new elements are now affecting the way providers think about small cells. C-RAN architecture is one of these game-changers: instead of the standalone cells containing a base station, radio and antenna, these centralized units perform baseband processing across multiple radios. Such high performance cells are perfectly suited for public spaces and large buildings. Furthermore, the economically sustainable large-scale deployment of small cells will require radically simple configurations methodologies. This is where “Plug-and-Play” is relevant: it means that when adding hardware to the network, the device’s configuration will be initiated automatically according to its environment and intended function. This will be a key element in any future small cell rollout, which providers cannot ignore. Finally, carriers should take note of the challenge posed by the growing importance of Heterogenous Networks. Referred to as HetNets, they combine a variety of wireless access nodes: macrocells, small cells, DAS and LANs, all typically from different providers. This phenomenon must be met with new regulations to ensure its coordination.
C-RAN, Plug-and-Play and Het-Nets are all evolving. However, if well implemented, these types of features and networks are expected to enable small cells to reach their full potential. Rough estimates have shown early on that increasing cell site numbers with small cells can improve capacity by up to 1600X and improve macro network performance by 315 per cent. These numbers are only expected to rise.
New Applications for a Familiar Technology
These new features offer new and exciting possibilities for an evolving technology, and have already become a catalyst of change in certain sectors. For example, easily implemented high performance small cells have a high potential for rural coverage use and for emergency response. This type of low-cost infrastructure enables coverage within even the smallest of communities. For example, the Japanese provider SoftBank Mobile has been a pioneer in this area, having installed over 3000 public access small cells on post offices throughout rural Japan. Providers in the UK and the US are following suit.
However, the talk of the town is indubitably the use of small cells in urban settings. In areas of high demand, operators deploy these on an open-access basis for all their customers. This market, not quite as developed as its residential and commercial counterparts, is poised to change the scenery: small cells are being installed in indoors and outdoors public spaces, on park benches, lamp posts and traffic lights. On the long-run, the significantly improved capacity brought forth by this type of network densification is thought to be one of the shapers of the upcoming shift towards 5G.
A Step Towards Hyperdense Networks
The takeaway is that while small cells have existed for over a decade, they are no longer just another novelty in a myriad of mobile network innovations. They have become an intrinsic part of all mobile provider’s 5-year plan as a response to the staggering rise in mobile data traffic. The deployment of hyperdense networks will not come without hurdles. Much of the technological and administrative methodology remains to be determined. Cooperation between providers will be essential as networks become deeply intertwined. While carriers are also working to improve spectrum efficiency and offload some of the demand through WI-Fi, none of these strategies come close to the capacity improvement brought forth by the use of small cells.