Perhaps what will do more than anything else to accelerate the integration of small cells will be virtualization technologies such as network functions virtualization (NFV), software defined networking (SDN) and self optimizing networks.
One thing that such technologies do is to eliminating reliance on expensive proprietary hardware platforms. NFV and SDN promise to reduce the capex of wireless networks and integrate networks under the HetNet umbrella.
By the end of 2020, SNS Research estimates that NFV and SDN investments on operator networks will account for nearly $21 Billion. These investments will primarily focus on mobile core/EPC, policy/IMS services, RAN (Radio Access Networks), OSS/BSS, data center, backhaul and CPE/home environment.