Sprint’s move to cut expenses by using microwave backhaul will require TM for long-term viability
Moving to microwave backhaul is one of the ways that Sprint is trying to cut expenses (Sprint Finalizes Plan to Trim Network Costs by Up to $1 Billion).
However, moving from leased fiber lines with near-unlimited bandwidth to microwave backhaul will require advances in spectral efficiency to keep up with user bandwidth demands as the demands of 5G begin to ramp up.
This article (.pdf) from Ericsson looks at some of the methods to improve spectral efficiency.
Significantly, the bandwidth of every method discussed can be doubled (or more) by employing Transpositional Modulation which can operate alongside an existing signal on the same carrier wave.