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.
