  The spectrum crunch challenge poses a vital threat to the progress of
cellular networks and recently prompted the inclusion of millimeter wave
(mmWave) and Upper 6GHz (U6G) in the 3GPP standards. These two bands promise to
unlock a large portion of untapped spectrum, but the harsh propagation due to
the increased carrier frequency might negatively impact the performance of
urban Radio Access Network (RAN) deployments. Within the span of a year, two
co-located 5G networks operating in these frequency bands were deployed at
Politecnico di Milano, Milan, Italy, entirely dedicated to the dense urban
performance assessment of the two systems. This paper presents an in-depth
analysis of the measurement campaigns conducted on them, with the U6G campaign
representing the first of its kind. A benchmark is provided by ray-tracing
simulations. The results suggest that networks operating in these frequency
bands provide good indoor and outdoor coverage and throughput in urban
scenarios, even when deployed in the macro base station setup common to lower
frequencies. In addition, a comparative performance analysis of these two key
technologies is provided, offering insights on their relative strengths,
weaknesses and improvement margins and informing on which bands is better
suited for urban macro coverage.
