989 research outputs found
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
Intelligent Reflective Surface Deployment in 6G: A Comprehensive Survey
Intelligent reflecting surfaces (IRSs) are considered a promising technology
that can smartly reconfigure the wireless environment to enhance the
performance of future wireless networks. However, the deployment of IRSs still
faces challenges due to highly dynamic and mobile unmanned aerial vehicle (UAV)
enabled wireless environments to achieve higher capacity. This paper sheds
light on the different deployment strategies for IRSs in future terrestrial and
non-terrestrial networks. Specifically, in this paper, we introduce key
theoretical concepts underlying the IRS paradigm and discuss the design aspects
related to the deployment of IRSs in 6G networks. We also explore
optimization-based IRS deployment techniques to improve system performance in
terrestrial and aerial IRSs. Furthermore, we survey model-free reinforcement
learning (RL) techniques from the deployment aspect to address the challenges
of achieving higher capacity in complex and mobile IRS-assisted UAV wireless
systems. Finally, we highlight challenges and future research directions from
the deployment aspect of IRSs for improving system performance for the future
6G network.Comment: 16 pages, 3 Figures, 7 table
Performance Analysis of Reconfigurable Intelligent Surface Assisted Two-Way NOMA Networks
This paper investigates the performance of reconfigurable intelligent surface
assisted two-way non-orthogonal multiple access (RIS-TW-NOMA) networks, where a
pair of users exchange their information through a RIS. The influence of
imperfect successive interference cancellation on RIS-TW-NOMA is taken into
account. To evaluate the potential performance of RIS-TW-NOMA, we derive the
exact and asymptotic expressions of outage probability and ergodic rate for a
pair of users. Based on the analytical results, the diversity orders and high
signal-to-noise ratio (SNR) slopes are obtained in the high SNR regime, which
are closely related to the number of RIS elements. Additionally, we analyze the
system throughput and energy efficiency of RIS-TW-NOMA networks in both
delay-limited and delay-tolerant transmission modes. Numerical results indicate
that: 1) The outage behaviors and ergodic rate of RIS-TW-NOMA are superior to
that of RIS-TW-OMA and two-way relay OMA (TWR-OMA); 2) As the number of RIS
elements increases, the RIS-TW-NOMA networks are capable of achieving the
enhanced outage performance; and 3) By comparing with RIS-TW-OMA and TWR-OMA
networks, the energy efficiency and system throughput of RIS-TW-NOMA has
obvious advantages
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