NYU (Rappaport), Texas (Heath), Stanford/Berkeley joined by TU Dresden and the University of Surrey. Monica Alleven at Fierce asked researchers where the outstanding work is being done and produced a report ranking the top universities. I can confirm that #1 NYU, #4 Stanford/Berkeley and their joint research and #5 University of Texas-Austin are among the most respected in the U.S. (I don't know academics outside the U.S. well enough to comment.)
Any American lead is fragile because research money is hard to find. Korea has committed $1.5B and the EU €700B for 5G research. Huawei, Samsung, Ericsson and Nokia are spending heavily. All the the big telecom companies in North America are gone. AT&T and Verizon are cutting capex and R&D.
Rappaport of NYU and Heath of Texas recently published what instantly became the standard textbook, Millimeter Wave Wireless Communications. Ted has been running his graduate students around Manhattan and Brooklyn testing prototype gear. The results have been strong and convinced most of the industry that high frequencies are part of the 5G story. Heath built a testbed for MU-MIMO, which Paulraj tells me is the way to reach rural homes.
(Millimeter waves are short-range.) Paulraj invented MIMO at Stanford and continues active research. Andrea Goldsmith of Stanford is advancing WiFi, which will be a crucial part of the future if the telcos don't gobble all the spectrum.
Alleven combines Stanford and Berkeley at #4 because of their long term collaboration on Software Defined Networking. SDN arose out of the graduate work of Martin Casado at Stanford in collaboration with Nick McKeown, also at Stanford, and Scott Shenker at Berkeley,
There's outstanding work being done in China, India and Iran. I'd welcome pointers to key researchers.