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Page 25 Ayass et al. Intell Robot 2022;22(1):20-36 https://dx.doi.org/10.20517/ir.2021.07

(2) There is an increased probability of errors and loss of information and data due to interference and
signal strength problems, impairing communication, data packet delivery, and network system reliability.

(3) There are mobility management challenges, due to the high mobility of these devices, constant change of
topology, and challenging coverage management and control processes. A sub-problem in this case is
related to the increase in altitude, which can generate other challenges.

(4) The reliability of communication and handovers between devices and equipment, also due to the high
mobility of UAVs, is lower, which can increase the delay, impair wireless communication, make it more
difficult to maintain communication links with higher quality, and bring new problems in the heterogeneity
of this type of networks, especially in the context of technologies linked to 4G and 5G. UAVs experience
dynamic channel swings and sudden changes due to high mobility and have constant problems with
handover and ping-pong effects.

(5) Challenges regarding the battery capacity of the devices, their replacement, the transformation of the
network and communications topology, and the computational and communications cost because of these
constant changes, among others, also exist .
[8]

3.2. Perspectives
However, in another direction, communications through UAVs also have numerous proposals and
possibilities for the future, as is constantly observed in current academic works, providing new possibilities
for multi-hop scenarios, which allow communication services for fixed and mobile devices and the creation
of new scenarios and dynamic ranges, quickly and reliably.

Among the possibilities that go beyond a communication system, we can highlight: (1) the use of UAVs for
people with special needs, providing visual information, among others, for those who need it; (2) delivery
services, constantly speeding up the competitive system of delivery of letters and products or assisting in
this type of need; (3) environmental monitoring systems, with sensors for agriculture, water resources,
temperature, and other monitoring systems, providing intelligent and dynamic decision-making; (4)
offering an important resource in military scenarios or places without infrastructure, including serving as a
base in scenarios of DTNs (delay tolerant networks); and (5) intelligent transport systems, helping to
monitor and control traffic, accidents, and other unexpected scenarios using UAVs. Other benefits include
inspection of electrical systems, use in telepresence and telemedicine, assistance in disaster and accident
scenarios, smart cities, etc.

Thus, it can be said that the use of UAVs in wireless networks is contributing and taking network
communications to a new level, integrating existing 4G and 5G networks with mobile device systems that
dynamically and constantly recreate new scenarios, providing topologies, greater ranges and transmission
rates, airbase station services, supporting terrestrial communications networks, helping in communication
between devices and IoT environments in healthcare systems, transport with the accident detection,
[9]
communication between vehicles, and energy management .

4. RELATED WORK
This section describes related published work on handover decision techniques on UAV networks. These
are mainly about strategies to ensure an efficient handover to maintain service continuity and acceptable
performance in delivering content to users.