Statistical analysis and channel modeling in next generation wireless communication systems

Abstract

In this thesis, statistical analysis and channel modeling in next generation wireless communication systems is presented in detail. The primary focus of this thesis is on the statistical modeling of interference temperature (IT) in cognitive radio systems, and empirical study of wireless channel characterization of unmanned aerial vehicle (UAV)-assisted communications at ultra-wideband (UWB) and at millimeter wave (mmWave) frequencies.

Firstly, in the cognitive radio system, a novel idea to statistically model the dynamic interference threshold (IT) from user traffic demand is presented in detail. It is shown that the cognitive radio system with dynamic IT will have high capacity performance with less outage probability over a system that does not utilize dynamic IT. The detailed theoretical analysis with expressions for mean capacity and outage probability in general operation region, and in high power region are derived and subsequently, validated with the simulations results. In addition, the effect of secondary user interference on primary user is also examined in this part.

In the second part, wireless channel characterisation for unmanned aerial vehicle-to-wearables (UAV2W) at UWB frequency is analysed, and studied empirically in an indoor warehouse environment. The frequency and distance dependent path gain analysis at different bandwidths for a corresponding carrier frequency with time dispersion characteristics is presented in detail. Furthermore, from statistical modeling, it was shown that the Log-normal distribution is the best fit distribution model to characterize fading in these UAV2W systems.

Finally, a novel emulation method for UAV motion by a robotic arm is presented to study the mmWave channel characteristics (Doppler spreading and path loss) at 28 GHz. In addition to that, empirical study is carried out to analyze the propeller modulation effect caused by the propellers in UAVs with an actual UAV setup. These important statistical analysis, and channel modeling discussed in this thesis are very critical in designing, analysing, and in implementation of fifth generation (5G) and beyond 5G (B5G) communication for the future. This thesis is a stepping stone in that direction.