Small Cells – an Evolution or a Revolution?

To overcome the 1000x traffic‐growth challenge, some key enabling 5G technologies have been proposed, including massive multiple input multiple output, millimetre‐wave transmission, dense small‐cell (SC) deployment, filtered orthogonal frequency‐division multiplexing, full duplex communications, polar codes, spatial division multiple access, native support of machine‐to‐machine communications etc. Initially, this chapter introduces a brief history of SC development and its concepts. Then, it illustrates the network architecture of HetNet. After this, the three main challenges in SC deployment, namely interference management, mobility management, and backhaul, are discussed. The chapter provides case studies for SC deployment in outdoor and indoor scenarios using a network planning tool. Finally, it represents some future SC evolutions.