6.1. Experimental Testbeds There is hardly any complete real-world testbed that
fully characterizes the challenges and benefits of cellular-
connected UAVs. The literature in this regard is scarce.
However, several ongoing efforts are being actively pursued
by researchers from both industry and academia to advance
the working prototypes. It is worth mentioning that, re-
alization of working prototypes of cellular-connected UAV
mainly differ with respect to (i) the main objective for which
they are built, and (ii) the features being implemented, which
are also dependent on the main objective. For example, one
prototype may completely focus its prototype development
on investigating 5G/B5G network support to efficient UAV
operations. Another prototype may prioritize its develop-
ment on achieving a fail-safe, reliable communication with
desired QoS guarantees. Furthermore, each prototype may
utilize different hardware and software flight stacks to real-
ize the goal. The chosen hardware and software platforms
may be open-source or proprietary in nature. Hence, the ex-
isting efforts tend to be very specific to the goal being pur-
sued, thereby providing unique characteristics or behaviours
to the prototype being developed. There are no formal de-
velopment guidelines available so far in order to harmonize
available features for these prototyping efforts.
An ideal view of cellular-connected UAV prototype is
still missing. This ideal prototype can be thought of pos-
sessing a non-trivial list of mandatory features and should
be adaptable to varying needs of the mission. Our current
work attempts to foresight such an ideal prototype and enu-
merates the list of encompassing features. Table
8
illustrates
a feature-oriented comparison of existing testbed works in
literature with the desirable set of features from an ideal pro-
totype point of view. Note that, this list of features is not ex-
haustive, rather provides a use-case driven analogy to con-
solidate the basic set of mandatory features. New features
may arise in future with evolution of emerging use cases for
cellular-connected UAVs.
In this subsection, we aim at investigating the existing ef-
forts to design and develop working prototypes for realizing
some UAV operations over LTE/4G/5G/B5G cellular net-
work infrastructure along with their implemented features.
They are presented as follows.
An open-source 4G connected and controlled self-flying
UAV is demonstrated in [
90
], defining a new, light-weight,
Table 7
List of avionics components used in [
90
]
Component
Model
Flight Controller
Omnibus F4 Pro
GPS
BN-220
Radio Rx
TBS Nano
Camera & Video Tx
TX05
Computer
Raspberry Pi Zero W
4G Modem
Verizon USB730L
4G Antenna
TS9
secure and open-source class of cellular-connected UAV.
This work utilizes open-source hardware and software stack
to design and develop fully autonomous and fail-safe flight
behaviour. This work provides a comprehensive and de-
tailed discussion on the possible hardware and software op-
tions for flight controllers, radio receivers, sensors, micro-
controllers and 4G cellular modems. Fig.
15
summarizes the
hardware and software components used in the prototype de-
velopment. The detailed hardware avionics schematics and
equipment models are highlighted in Fig.
16
and Table
7
,
respectively. The performance of the prototype is tested for
endurance, terrain alignment, autonomous flying behaviour,
wind speed and real-time video quality. The important ac-
complishments of this work are summarized as follows.
• The entire prototype setup is done by open-source
hardware and software components with Commercial
off-the-shelf (COTS) components.
• The UAV shows longest demonstrated flight time i.e.,
over one hour.
• This work provides clear, concise and step-to-step
guidelines for entire prototype design and devel-
opment along with the programming of individual
pieces. This also includes an online manual (wiki) and
supplementary information.
Figure 15:
Prototype design and configurations in [
90
]
Figure 16:
Schematic of the avionics components in [
90
]
D. Mishra et al.:
