28 GHz Millimeter-Wave Ultrawideband Small-Scale Fading Models in Wireless Channels

TL;DR

This study measures small-scale fading in 28 GHz millimeter-wave channels, revealing Rician-distributed power delay profiles and spatial autocorrelation properties crucial for modeling and simulating outdoor mmWave wireless channels.

Contribution

It provides detailed small-scale fading models and autocorrelation functions for 28 GHz outdoor channels, aiding in accurate channel simulation and system design.

Findings

Voltage amplitudes follow Rician distribution with specific K-factors.

Signal amplitudes decorrelate after 2-5 wavelengths depending on scenario.

Models help recreate path gain statistics for mmWave channel simulations.

Abstract

This paper presents small-scale fading measurements for 28 GHz outdoor millimeter-wave ultrawideband channels using directional horn antennas at the transmitter and receiver. Power delay profiles were measured at half-wavelength spatial increments over a local area (33 wavelengths) on a linear track in two orthogonal receiver directions in a typical base-to-mobile scenario with fixed transmitter and receiver antenna beam pointing directions. The voltage path amplitudes are shown to follow a Rician distribution, with K-factor ranging from 9 - 15 dB and 5 - 8 dB in line of sight (LOS) and non-line of sight (NLOS) for a vertical-to-vertical co-polarized antenna scenario, respectively, and from 3 - 7 dB in both LOS and NLOS vertical-to-horizontal cross-polarized antenna scenario. The average spatial autocorrelation functions of individual multipath components reveal that signal amplitudes reach a correlation of 0 after 2 and 5 wavelengths in LOS and NLOS co-polarized V-V antenna scenarios. The models provided are useful for recreating path gain statistics of millimeter-wave wideband channel impulse responses over local areas, for the study of multi-element antenna simulations and channel estimation algorithms.