Coverage Enhancement for mm Wave Communications using Passive Reflectors

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 mm Wave 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 mm Wave 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 ray tracing 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 × 24 in2 and 33 × 33 in2, 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.