Rick, what the paper describes is otherwise known as MIMO. Each AP transmits a signal on the same frequency channel. As long as the receivers can decorrelate the propagation paths from the different APs, they can reconstruct the desired signal.
In traditional MIMO, each transmitter sends multiple beams in different directions, and each receiver would combine the bit streams from all of the propagation paths. In this DIDO, it looks like each receiver is only interested in one of the propagation paths, rather than aggregating the signals from all of the paths. The net effect is the same, though.
These are clever techniques that APPEAR to violate Shannon's limit, but in fact they don't. They depend on decorrelated propagation paths, much as you would have if you used multiple separate cables in parallel. If the signals paths become more correlated, you will lose that spectral efficiency. For example, bring the APs physically very close together compared with the distance to the receivers. That sort of thing makes it difficult to decorrelate the different propagation paths.
Drones are, in essence, flying autonomous vehicles. Pros and cons surrounding drones today might well foreshadow the debate over the development of self-driving cars. In the context of a strongly regulated aviation industry, "self-flying" drones pose a fresh challenge. How safe is it to fly drones in different environments? Should drones be required for visual line of sight – as are piloted airplanes? Join EE Times' Junko Yoshida as she moderates a panel of drone experts.