One of the major things not really addressed in the article is backhaul for each 4.5G/5G cell site or small cell site. More air spectrum and better radio modulation/MIMO for the cell-to-handset is very important, but that's only a piece of the puzzle...
There's still a lot of locations out there without fiber, or that are currently fed by a 250-400Mbps capacity PTP microwave link. Cellular carriers are aggressively spending money to bring dark fiber to tower sites, of course, with the minimum connectivity for a new site being a single 10GbE circuit. This is one of the things driving the growth of outside-plant fiber construction and dedicated-purpose dark fiber network operators (example: Zayo's ongoing new builds spending $$$$$ in major metro areas in Texas).
The other part of the puzzle is much higher capacity new PTP microwave to feed sites, some of which will be logically downstream of newly fiber-fed sites. These new links will be at 1 Gbps to 5Gbps+ capacity.
There's still a lot of locations out there without fiber, or that are currently fed by a 250-400Mbps capacity PTP microwave link. Cellular carriers are aggressively spending money to bring dark fiber to tower sites, of course, with the minimum connectivity for a new site being a single 10GbE circuit. This is one of the things driving the growth of outside-plant fiber construction and dedicated-purpose dark fiber network operators (example: Zayo's ongoing new builds spending $$$$$ in major metro areas in Texas).
The other part of the puzzle is much higher capacity new PTP microwave to feed sites, some of which will be logically downstream of newly fiber-fed sites. These new links will be at 1 Gbps to 5Gbps+ capacity.