  Millimeter wave (mmWave) technology is expected to dominate the future 5G
networks mainly due to large spectrum available at these frequencies. However,
coverage deteriorates significantly at mmWave frequencies due to higher path
loss, especially for the non-line-of-sight (NLOS) scenarios. In this work, we
explore the use of passive reflectors for improving mmWave signal coverage in
NLOS indoor areas. Measurements are carried out using the PXI-based mmWave
transceiver platforms from National Instruments operating at 28 GHz, and the
results are compared with the outcomes of ray tracing (RT) simulations in a
similar environment. For both the measurements and RT simulations, different
shapes of metallic passive reflectors are used to observe the coverage (signal
strength) statistics on a receiver grid in an NLOS area. For a square metallic
sheet reflector of size 24 by 24 in and 33 by 33 in , we observe a significant
increase in the received power in the NLOS region, with a median gain of 20 dB
when compared to no reflector case. The cylindrical reflector shows more
uniform coverage on the receiver grid as compared to flat reflectors that are
more directional.
