UAV-Assisted mmWave and THz-Enabled Hybrid Heterogeneous Network

Abstract

Heterogeneous networks (HetNets) are becoming a promising solution for future wireless systems to satisfy the high data rate requirements. Specifically, with the advent of millimeter wave (mmWave) and TeraHertz (THz) communication, there is a need to redesign and analyze the conventional cellular systems. Unmanned

Aerial Vehicles (UAVs) are becoming an integral part of communication frame- work in an HetNet owing to its fast mobility and quick deployment in crowdy or

disastrous hit areas. UAVs can be deployed to offload heavy traffic in scenarios

such as a football match in a stadium or to provide infrastructure if existing com- munication infrastructure get destroyed such as by an earthquake or a storm. This

research focuses on the analysis of SINR and rate coverage probabilities in a Het- Net comprising of above mentioned technologies. This research also considered

wireless backhauling to the core network by replacing cumbersome wired chan- nels to the core. This research also introduces a stochastic geometry framework

for the analysis of downlink coverage probability in a multi-tier HetNet consist- ing of macro-base station (MBS) operating at sub-6 GHz, mmWave small BSs

and unmanned aerial vehicles (UAVs) operating at 28 GHz and THz frequencies enabled BSs. The effectiveness of the HetNet is analyzed on various performance

metrics including association and coverage probabilities for different network pa- iii

rameters. The analytical expressions for the coverage probability for each tier have been derived in this research. Monte Carlo simulations have been performed to evaluate the significance of the model. It has been shown that the mmWave and THz-enabled cells provide significant improvement in the achievable data rates because of their high available bandwidth, however, they have a degrading effect on the coverage probabilities due to their high propagation losses. It has also been shown that UAVs due to its mobile deployment provide better coverage to end users where signals from the conventional MBS does not have enough strength. This research also highlight a suitable combination of tier densities required to achieve the QoS requirements.