10 research outputs found
Trajectory Optimization and Phase-Shift Design in IRS Assisted UAV Network for High Speed Trains
The recent trend towards the high-speed transportation system has spurred the
development of high-speed trains (HSTs). However, enabling HST users with
seamless wireless connectivity using the roadside units (RSUs) is extremely
challenging, mostly due to the lack of line of sight link. To address this
issue, we propose a novel framework that uses intelligent reflecting surfaces
(IRS)-enabled unmanned aerial vehicles (UAVs) to provide line of sight
communication to HST users. First, we formulate the optimization problem where
the objective is to maximize the minimum achievable rate of HSTs by jointly
optimizing the trajectory of UAV and the phase-shift of IRS. Due to the
non-convex nature of the formulated problem, it is decomposed into two
subproblems: IRS phase-shift problem and UAV trajectory optimization problem.
Next, a Binary Integer Linear Programming (BILP) and a Soft Actor-Critic (SAC)
are constructed in order to solve our decomposed problems. Finally,
comprehensive numerical results are provided in order to show the effectiveness
of our proposed framework.Comment: This paper has been submitted to IEEE Wireless Communications Letter
Full-Dimensional Rate Enhancement for UAV-Enabled Communications via Intelligent Omni-Surface
This paper investigates the achievable rate maximization problem of a
downlink unmanned aerial vehicle (UAV)-enabled communication system aided by an
intelligent omni-surface (IOS). Different from the state-of-the-art
reconfigurable intelligent surface (RIS) that only reflects incident signals,
the IOS can simultaneously reflect and transmit the signals, thereby providing
full-dimensional rate enhancement. To tackle such a problem, we formulate it by
jointly optimizing the IOS's phase shift and the UAV trajectory. Although it is
difficult to solve it optimally due to its non-convexity, we propose an
efficient iterative algorithm to obtain a high-quality suboptimal solution.
Simulation results show that the IOS-assisted UAV communications can achieve
more significant improvement in achievable rates than other benchmark schemes.Comment: 6 pages, 5 figure
IRS-aided UAV for Future Wireless Communications: A Survey and Research Opportunities
Both unmanned aerial vehicles (UAVs) and intelligent reflecting surfaces
(IRS) are gaining traction as transformative technologies for upcoming wireless
networks. The IRS-aided UAV communication, which introduces IRSs into UAV
communications, has emerged in an effort to improve the system performance
while also overcoming UAV communication constraints and issues. The purpose of
this paper is to provide a comprehensive overview of IRSassisted UAV
communications. First, we provide five examples of how IRSs and UAVs can be
combined to achieve unrivaled potential in difficult situations. The
technological features of the most recent relevant researches on IRS-aided UAV
communications from the perspective of the main performance criteria, i.e.,
energy efficiency, security, spectral efficiency, etc. Additionally, previous
research studies on technology adoption as machine learning algorithms. Lastly,
some promising research directions and open challenges for IRS-aided UAV
communication are presented
IRS-assisted UAV Communications: A Comprehensive Review
Intelligent reflecting surface (IRS) can smartly adjust the wavefronts in
terms of phase, frequency, amplitude and polarization via passive reflections
and without any need of radio frequency (RF) chains. It is envisaged as an
emerging technology which can change wireless communication to improve both
energy and spectrum efficiencies with low energy consumption and low cost. It
can intelligently configure the wireless channels through a massive number of
cost effective passive reflecting elements to improve the system performance.
Similarly, unmanned aerial vehicle (UAV) communication has gained a viable
attention due to flexible deployment, high mobility and ease of integration
with several technologies. However, UAV communication is prone to security
issues and obstructions in real-time applications. Recently, it is foreseen
that UAV and IRS both can integrate together to attain unparalleled
capabilities in difficult scenarios. Both technologies can ensure improved
performance through proactively altering the wireless propagation using smart
signal reflections and maneuver control in three dimensional (3D) space. IRS
can be integrated in both aerial and terrene environments to reap the benefits
of smart reflections. This study briefly discusses UAV communication, IRS and
focuses on IRS-assisted UAC communications. It surveys the existing literature
on this emerging research topic and highlights several promising technologies
which can be implemented in IRS-assisted UAV communication. This study also
presents several application scenarios and open research challenges. This study
goes one step further to elaborate research opportunities to design and
optimize wireless systems with low energy footprint and at low cost. Finally,
we shed some light on future research aspects for IRS-assisted UAV
communication
A Comprehensive Overview on 5G-and-Beyond Networks with UAVs: From Communications to Sensing and Intelligence
Due to the advancements in cellular technologies and the dense deployment of
cellular infrastructure, integrating unmanned aerial vehicles (UAVs) into the
fifth-generation (5G) and beyond cellular networks is a promising solution to
achieve safe UAV operation as well as enabling diversified applications with
mission-specific payload data delivery. In particular, 5G networks need to
support three typical usage scenarios, namely, enhanced mobile broadband
(eMBB), ultra-reliable low-latency communications (URLLC), and massive
machine-type communications (mMTC). On the one hand, UAVs can be leveraged as
cost-effective aerial platforms to provide ground users with enhanced
communication services by exploiting their high cruising altitude and
controllable maneuverability in three-dimensional (3D) space. On the other
hand, providing such communication services simultaneously for both UAV and
ground users poses new challenges due to the need for ubiquitous 3D signal
coverage as well as the strong air-ground network interference. Besides the
requirement of high-performance wireless communications, the ability to support
effective and efficient sensing as well as network intelligence is also
essential for 5G-and-beyond 3D heterogeneous wireless networks with coexisting
aerial and ground users. In this paper, we provide a comprehensive overview of
the latest research efforts on integrating UAVs into cellular networks, with an
emphasis on how to exploit advanced techniques (e.g., intelligent reflecting
surface, short packet transmission, energy harvesting, joint communication and
radar sensing, and edge intelligence) to meet the diversified service
requirements of next-generation wireless systems. Moreover, we highlight
important directions for further investigation in future work.Comment: Accepted by IEEE JSA