Millimeter Wave Small-Scale Spatial Statistics in an Urban Microcell Scenario

TL;DR

This study characterizes small-scale spatial fading and autocorrelation at 73 GHz in an urban microcell environment, providing insights for 5G MIMO system design with detailed measurements in LOS and NLOS conditions.

Contribution

It offers the first detailed outdoor millimeter-wave small-scale spatial statistics in a real urban setting, including fading distributions and autocorrelation models for 5G applications.

Findings

Ricean distribution fits most small-scale fading data

Exponential models describe autocorrelation in LOS and NLOS

Decorrelation distances vary with receiver track orientation

Abstract

This paper presents outdoor wideband small-scale spatial fading and autocorrelation measurements and results in the 73 GHz millimeter-wave (mmWave) band conducted in downtown Brooklyn, New York. Both directional and omnidirectional receiver (RX) antennas are studied. Two pairs of transmitter (TX) and RX locations were tested with one line-of-sight (LOS) and one non-line-of-sight (NLOS) environment, where a linear track was employed at each RX to move the antenna in half-wavelength increments. Measured data reveal that the small-scale spatial fading of the received signal voltage amplitude are generally Ricean-distributed for both omnidirectional and directional RX antenna patterns under both LOS and NLOS conditions in most cases, except for the log-normal distribution for the omnidirectional RX antenna pattern in the NLOS environment. Sinusoidal exponential and typical exponential functions are found to model small-scale spatial autocorrelation of the received signal voltage amplitude in LOS and NLOS environments in most cases, respectively. Furthermore, different decorrelation distances were observed for different RX track orientations, i.e., for different directions of motion relative to the TX. Results herein are valuable for characterizing small-scale spatial fading and autocorrelation properties in multiple-input multiple-output (MIMO) systems for fifth-generation (5G) mmWave frequencies.