Statistical Blockage Modeling and Robustness of Beamforming in Millimeter-Wave Systems

TLDR: The results show that network densification, subarray switching in a user equipment designed with multiple subarrays, fall back mechanisms, etc., can address blockage before it leads to a deleterious impact on the mmW link margin.

Abstract: There has been a growing interest in the commercialization of millimeter-wave (mmW) technology as a part of the fifth-generation new radio wireless standardization efforts. In this direction, many sets of independent measurements show that the biggest determinants of viability of mmW systems are penetration and blockage of mmW signals through different materials in the scattering environment. With this background, the focus of this paper is on understanding the impact of blockage of mmW signals and reduced spatial coverage due to penetration through the human hand, body, vehicles, and so on. Leveraging measurements with a 28-GHz mmW experimental prototype and electromagnetic simulation studies, we first propose statistical models to capture the impact of the hand, human body, and vehicles. We then study the time scales at which mmW signals are disrupted by blockage (hand and human body). Our results show that these events can be attributed to physical movements, and the time scales corresponding to blockage are, hence, on the order of a few 100 ms or more. Network densification, subarray switching in a user equipment designed with multiple subarrays, fall back mechanisms, etc., can address blockage before it leads to a deleterious impact on the mmW link margin.