  This paper describes wideband (1 GHz) base station diversity and coordinated
multipoint (CoMP)-style large-scale measurements at 73 GHz in an urban
microcell open square scenario in downtown Brooklyn, New York on the NYU
campus. The measurements consisted of ten random receiver locations at
pedestrian level (1.4 meters) and ten random transmitter locations at lamppost
level (4.0 meters) that provided 36 individual transmitter-receiver (TX-RX)
combinations. For each of the 36 radio links, extensive directional
measurements were made to give insights into small-cell base station diversity
at millimeter-wave (mmWave) bands. High-gain steerable horn antennas with
7-degree and 15-degree half-power beamwidths (HPBW) were used at the
transmitter (TX) and receiver (RX), respectively. For each TX-RX combination,
the TX antenna was scanned over a 120-degree sector and the RX antenna was
scanned over the entire azimuth plane at the strongest RX elevation plane and
two other elevation planes on both sides of the strongest elevation angle,
separated by the 15-degree HPBW. Directional and omnidirectional path loss
models were derived and match well with the literature. Signal reception
probabilities derived from the measurements for one to five base stations that
served a single RX location show significant coverage improvement over all
potential beamformed RX antenna pointing angles. CDFs for nearest neighbor and
Best-N omnidirectional path loss and cell outage probabilities for directional
antennas provide insights into coverage and interference for future mmWave
small-cells that will exploit macro-diversity and CoMP.
