Multi-band Millimetre Wave
Channel Measurements and Analysis in Multiple Scenarios for Future Wireless Networks

Abstract

This thesis presents an analysis of multi-band radio channel characteristic measurements in both indoor and outdoor environments for future wireless networks. The measurements were taken using a wideband chirp sounder developed at Durham University. The thesis includes an analytical review of radio wave propagation mechanisms and models, as well as a background to the channel characteristics parameters and statistics. The parameters reviewed include received signal strength, path loss, excess, RMS delay spread, Ricean K factor, channel capacity, and angular parameters such as the angle of arrival (AoA) and angle of departure (AoD). Additionally, the thesis examines clutter and building entry loss, as well as the effect of snow on radio links with different setups.
The thesis describes a series of measurement setups that were applied to study the characteristics of radio waves in different environments and conditions. The first setup was performed in an indoor environment, where multi-band radio channel characteristics were measured. The measurement results were used to develop an Alpha-Beta-Gamma (ABG) path loss model for both line-of-sight and non-line-of-sight propagation scenarios. Delay spread and K-factor frequency dependency for nine frequency bands ranging from below 1 GHz up to 73GHz were also presented. The second setup investigated the effects of beam misalignment on radio channel characteristics in an outdoor environment at specific frequencies. This study aimed to determine how beam misalignment affects radio signals and to what extent it can degrade the quality of the transmission. The third setup aimed to highlight the importance of implementing Multiple-Input Multiple-Output (MIMO) systems to increase channel capacity instead of increasing the signal-to-noise ratio for Single-Input Single-Output (SISO) links. This study focused on demonstrating how MIMO technology can improve the reliability and capacity of wireless communication systems. The fourth setup involved building a frequency dependency model for clutter and building entry loss using the ABG model. This study aimed to develop a model that accurately predicts the impact of clutter and building entry loss on radio signals. The final setup investigated how snowfall affects radio waves with different polarisation setups, co-polarisation and cross-polarisation. The study aimed to determine how snow affects radio signal polarisation and its impact on the quality of transmission.

In conclusion, the thesis encompassed various experiments: indoor multi-frequency measurements from 0.6 to 73 GHz aiming to update ITU indoor models; outdoor directional mm-wave measurements exploring beam misalignment effects on path loss, RMS DS, and angular spread; investigations into 8x8 MIMO and 8x1 MISO systems at 25 GHz revealing delay spread disparities in different scenarios; wideband clutter assessments at 28, 39, and 85 GHz showcasing their impact on path and clutter loss, correlating with frequency and distance; and snow's impact on radio wave propagation at 25 GHz and 77 GHz, with cross-polarisation setups experiencing higher attenuation. These comprehensive analyses shed light on wireless system behaviour in diverse environments and factors influencing their efficacy, offering insights crucial for system design and performance enhancement, especially at higher frequencies. the study provided valuable insights into the characteristics of radio wave propagation in different environments and conditions. The results can be used to improve the design and performance of wireless communication systems.