HetNet refers to the provision of a cellular network through a combination of different cell types (e.g. macro, pico or femto cells) and different access technologies (i.e. 2G, 3G, 4G, Wi-fi). By integrating a number of diverse technologies depending on the topology of the coverage area, operators can potentially provide a more consistent customer experience compared to what could be achieved with a homogenous network. Small cell deployments are a key feature of the HetNet approach as they allow considerable flexibility as to where they are positioned, however, the use of more cells brings implications in terms of power supply and backhaul, especially when they are located in remote areas. Wi-fi can also play a significant role in HetNets, both in terms of data offload and roaming. GSMA Intelligence Understanding 5G 15 HetNet technology has typically been developed in relation to data networking, but recently voice has been brought under the scope as well, not least because of support for Wi-fi calling being available in Apple’s iPhone 6 which was released in September 2014.