According to a whitepaper that was published late last year by ThinkSmallCell:
There are commonly thought to be three ways to densify wireless traffic capacity:
1. More spectrum (expensive, limited)
2. More spectrally efficiency (e.g. LTE rather than 2G)
3. More spatial reuse (i.e. small cells)
But there is also a fourth aspect which can deliver significant additional benefit
4. Orchestration and tighter control. (e.g. SON (Self Organising Networks), traffic steering/shaping across and between all available wireless resources)
This has been a key factor driving replacement of outdated macrocells with “Single RAN” basestation equipment that supports all generations of radio interface. These specifically address (1) and (2) above. What’s needed next is investment in tools and equipment that provides similar flexibility for (3) and (4), scaling to cope with an influx of small cells and introducing real-time management and co-ordination across all available wireless technologies, both cellular and Wi-Fi.
While we dont generally hear a lot about SON nowadays, I know most of the vendors have implemented some or the other aspects of SON in their equipment. Orchestration can definitely have a much bigger impact than SON by itself on the densification.
In 5G, we talk about 'edgeless cells', 'no-edge networks', etc. Orchestration of the network will have a big part to play in this too.
Anyway, here is the whitepaper embedded below and available to download from Slideshare