Small cells promise to boost capacity and throughput in areas of high usage more cheaply than macro cell deployments, while allowing more efficient use of spectrum than macros, and providing improved coverage at the cell edge and indoors. Bringing the radio signal closer to the user should also help to improve device battery life.
All of the major infrastructure vendors have announced some degree of support for small cells in their product portfolios, be it picocell, femtocell, small-cell RAN, Wi-Fi or a combination of these. But far from being purely vendor driven, the need to rethink the macro model is getting equally strong support from mobile operators, many of whom have already embraced small cells through their growing use of alternative technologies such as wireless LANs and femtocells as a means of offloading data traffic from the cellular network or extending coverage.
Judging by the deliberations at Informa Telecoms & Media’s Small Cells World Congress in Berlin (October 11-12) a consensus already exists that adherence to the macro-cell network model cannot in itself provide sufficient capacity to meet future traffic demand. But that doesn’t make small cells a done deal, and it was clear that there are more questions than answers when it comes to implementing a small cell strategy.
Key areas of concern for the delegates in Berlin included how to make the best choice of small cell technology, tackling interference issues, hotspot identification (in order to better target small cell deployments), backhaul provision, managing small cells in a multi-vendor environment, handover between the macro network and small cell sites, self-organizing capabilities (SONs), and the challenges of distributed architectures and cloud-RAN.
Wi-Fi/femtocell convergence
Wi-Fi remains very much on the agenda for many mobile operators, but there was a clear desire to integrate the technology more closely with cellular both in terms of ease of use (network discovery, authentication and log-on) and at the core network level. Femtocells were generally agreed to have fewer integration challenges in terms of authentication and security than Wi-Fi, but interference problems between what some regarded as “unplanned” consumer femtocell deployments and the macro network remained a concern for some operators, notably Deutsche Telekom and Orange.