Unmanned aerial vehicle (UAV) technology has gained a great interest in communication
systems due to its ability to host a cellular base station (BS) and thus act as an aerial BS
(UAV-BS). The inheritance of mobility in the airspace makes the deployment of UAV-BSs
flexible and agile aiming to mainly complement the terrestrial network, extend its coverage,
and serve as a capacity injector in high-throughput demand scenarios. Besides, a
UAV can also act as an aerial user (UAV-UE) for various use cases, such as aerial data
collection and cargo delivery. Such UAV-UE missions need reliable cellular communication
links in order to safely operate in beyond visual line-of-sight (BVLoS). Since terrestrial
networks were not primarily designed to serve aerial users, due to their down-tilted BS
antennas, re-coursing solely to these networks for aerial users’ cellular connectivity might
not be a viable approach as a long-term solution. Alternatively, deploying UAV-BSs in
this context can substantially improve both aerial and terrestrial users coverage and capacity.
One of the challenging issues is how to characterize the UAV-UE performance in
integrated aerial/terrestrial networks, called vertical heterogeneous networks (VHetNets).
First, we thoroughly study the aerial user’s performance in terms of coverage probability
in a VHetNets setup. Under a more realistic system model, we revisit the coverage
and throughput performances of an aerial user in VHetNets, considering LoS and non-LoS
(NLoS) transmissions and under different spectrum sharing policies among separate aerial
and terrestrial networks. Some insights have been concluded on the integration of aerial
BSs and UAV-UEs with the existing terrestrial network. Specifically, optimal positioning
of UAV-BSs for maximized aerial users coverage was investigated for various aerial users
distribution and spectrum allocations. Moreover, visioning that UAV technology will revolutionize
the cargo delivery industry, we proposed a new concept of 3D aerial highways,
which designs coordinated routes for a massive number of UAVs used mainly for delivery
purposes. In this context, multiple network technologies were proposed and discussed to
guarantee the cellular connectivity of cargo-UAVs in 3D aerial highways. For the particular
case of connectivity supported by terrestrial cellular networks, an optimal energy-efficient
and low-handoff trajectory planning for a cargo-UAV mission was proposed, with respect to disconnectivity constraints. Consequently, associated design guidelines and recommendations
have been drawn. Leveraging reinforcement learning (RL) tools, we proposed a
novel algorithm for path planning and cell association for the cargo-UAV that maximizes
its cellular service reliability and minimizes the handoff events. Finally, we introduced a
new paradigm, intermittently tethered UAV (iTUAV), as a trade-off between mobility and
energy availability for providing cellular connectivity in temporary events.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/44224 |
| Date | 01 November 2022 |
| Creators | Cherif, Nesrine |
| Contributors | Yongacoglu, Abbas M., Yanikomeroglu, Halim |
| Publisher | Université d'Ottawa / University of Ottawa |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
| Rights | CC0 1.0 Universal, http://creativecommons.org/publicdomain/zero/1.0/ |
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