cell planning required. At the beginning of the small cell industry, with residential femtocells, a consumer would buy, or be given, a femtocell, which self-installed. With today's indoor enterprise and outdoor small cell networks, this has changed as an operator or system inte- grator will install each cell; however, due to limited site choice, self-optimization is still popular as it makes it easier for a small cell network to adjust parameters to ensure it oper- ates efficiently. To reduce the complexity and cost of both maintenance and management of small cell networks, Network Function Virtualization and Software Defined Networks (NFV/SDN) can be used. This technique has been most extensively adopted for core networks but can also extend to the RAN. An NFV/SDN network separates control and data planes and abstracts network functions from underlying hardware. This makes it easier to scale up 4 NG-RAN Architecture and down processing as required and easier to automate control of the network functions. The improved manageability of virtualized networks is a big driver for their adoption. 4.6.3.3 Backhaul Providing a suitable backhaul connection to a small cell site is a major challenge, and bar- rier, for the expansion of small cell networks. The backhaul requirements of a small cell are less than a macro cell; however, there are significantly more cell sites and, as they are typically in urban locations, gaining a physical connection to a small cell site is a challenge. As a consequence of this difficulty multiple types of backhaul have been proposed to help solve the backhaul challenge for small cells (SCF 049): Fiber is the traditional backhaul for macro cells and where feasible is a good choice for small cells. Wireless, where both sub-6 GHz and mm Wave solutions have been implemented. Widely available wired networks such as broadband (digital subscriber line technologies [xDSL]) and cable networks. Satellite is an option useful for remote or rural small cell networks. Furthermore, technologies such as Inte