Coverage Enhancement for mmWave Communications using Passive Reflectors

TL;DR

This paper investigates the use of passive metallic reflectors to enhance mmWave signal coverage in NLOS indoor environments, demonstrating significant power gains and improved coverage uniformity through measurements and ray tracing simulations.

Contribution

It introduces a practical approach using passive reflectors at 28 GHz to improve mmWave coverage, validated by measurements and simulations.

Findings

Significant median power gain of 20 dB with square reflectors.

Cylindrical reflectors provide more uniform coverage.

Passive reflectors effectively enhance NLOS mmWave signal coverage.

Abstract

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.