399 research outputs found
Security enhancement for NOMA-UAV networks
Owing to its distinctive merits, non-orthogonal multiple access (NOMA) techniques have been utilized in unmanned aerial vehicle (UAV) enabled wireless base stations to provide effective coverage for terrestrial users. However, the security of NOMA-UAV systems remains a challenge due to the line-of-sight air-to-ground channels and higher transmission power of weaker users in NOMA. In this paper, we propose two schemes to guarantee the secure transmission in UAV-NOMA networks. When only one user requires secure transmission, we derive the hovering position for the UAV and the power allocation to meet rate threshold of the secure user while maximizing the sum rate of remaining users. This disrupts the eavesdropping towards the secure user effectively. When multiple users require secure transmission, we further take the advantage of beamforming via multiple antennas at the UAV to guarantee their secure transmission. Due to the non-convexity of this problem, we convert it into a convex one for an iterative solution by using the second order cone programming. Finally, simulation results are provided to show the effectiveness of the proposed scheme
On the Performance of Low-Altitude UAV-Enabled Secure AF Relaying with Cooperative Jamming and SWIPT
This paper proposes a novel cooperative secure unmanned aerial vehicle (UAV)
aided transmission protocol, where a source (Alice) sends confidential
information to a destination (Bob) via an energy-constrained UAV-mounted
amplify-and-forward (AF) relay in the presence of a ground eavesdropper (Eve).
We adopt destination-assisted cooperative jamming (CJ) as well as simultaneous
wireless information and power transfer (SWIPT) at the UAV-mounted relay to
enhance physical-layer security (PLS) and transmission reliability. Assuming a
low altitude UAV, we derive connection probability (CP), secrecy outage
probability (SOP), instantaneous secrecy rate, and average secrecy rate (ASR)
of the proposed protocol over Air-Ground (AG) channels, which are modeled as
Rician fading with elevation-angel dependent parameters. By simulations, we
verify our theoretical results and demonstrate significant performance
improvement of our protocol, when compared to conventional transmission
protocol with ground relaying and UAV-based transmission protocol without
destination-assisted jamming. Finally, we evaluate the impacts of different
system parameters and different UAV's locations on the proposed protocol in
terms of ASR.Comment: 10 pages, 9 figures, Submitted for possible journal publicatio
Relaying in the Internet of Things (IoT): A Survey
The deployment of relays between Internet of Things (IoT) end devices and gateways can improve link quality. In cellular-based IoT, relays have the potential to reduce base station overload. The energy expended in single-hop long-range communication can be reduced if relays listen to transmissions of end devices and forward these observations to gateways. However, incorporating relays into IoT networks faces some challenges. IoT end devices are designed primarily for uplink communication of small-sized observations toward the network; hence, opportunistically using end devices as relays needs a redesign of both the medium access control (MAC) layer protocol of such end devices and possible addition of new communication interfaces. Additionally, the wake-up time of IoT end devices needs to be synchronized with that of the relays. For cellular-based IoT, the possibility of using infrastructure relays exists, and noncellular IoT networks can leverage the presence of mobile devices for relaying, for example, in remote healthcare. However, the latter presents problems of incentivizing relay participation and managing the mobility of relays. Furthermore, although relays can increase the lifetime of IoT networks, deploying relays implies the need for additional batteries to power them. This can erode the energy efficiency gain that relays offer. Therefore, designing relay-assisted IoT networks that provide acceptable trade-offs is key, and this goes beyond adding an extra transmit RF chain to a relay-enabled IoT end device. There has been increasing research interest in IoT relaying, as demonstrated in the available literature. Works that consider these issues are surveyed in this paper to provide insight into the state of the art, provide design insights for network designers and motivate future research directions
UAV Swarm-Enabled Aerial CoMP: A Physical Layer Security Perspective
Unlike aerial base station enabled by a single unmanned aerial vehicle (UAV),
aerial coordinated multiple points (CoMP) can be enabled by a UAV swarm. In
this case, the management of multiple UAVs is important. This paper considers
the power allocation strategy for a UAV swarm-enabled aerial network to enhance
the physical layer security of the downlink transmission, where an eavesdropper
moves following the trajectory of the swarm for better eavesdropping. Unlike
existing works, we use only the large-scale channel state information (CSI) and
maximize the secrecy throughput in a whole-trajectory-oriented manner. The
overall transmission energy constraint on each UAV and the total transmission
duration for all the legitimate users are considered. The non-convexity of the
formulated problem is solved by using max-min optimization with iteration. Both
the transmission power of desired signals and artificial noise (AN) are derived
iteratively. Simulation results are presented to validate the effectiveness of
our proposed power allocation algorithm and to show the advantage of aerial
CoMP by using only the large-scale CSI
Secure Short-Packet Communications via UAV-Enabled Mobile Relaying: Joint Resource Optimization and 3D Trajectory Design
Short-packet communication (SPC) and unmanned aerial vehicles (UAVs) are
anticipated to play crucial roles in the development of 5G-and-beyond wireless
networks and the Internet of Things (IoT). In this paper, we propose a secure
SPC system, where a UAV serves as a mobile decode-and-forward (DF) relay,
periodically receiving and relaying small data packets from a remote IoT device
to its receiver in two hops with strict latency requirements, in the presence
of an eavesdropper. This system requires careful optimization of important
design parameters, such as the coding blocklengths of both hops, transmit
powers, and UAV's trajectory. While the overall optimization problem is
nonconvex, we tackle it by applying a block successive convex approximation
(BSCA) approach to divide the original problem into three subproblems and solve
them separately. Then, an overall iterative algorithm is proposed to obtain the
final design with guaranteed convergence. Our proposed low-complexity algorithm
incorporates 3D trajectory design and resource management to optimize the
effective average secrecy throughput of the communication system over the
course of UAV-relay's mission. Simulation results demonstrate significant
performance improvements compared to various benchmark schemes and provide
useful design insights on the coding blocklengths and transmit powers along the
trajectory of the UAV
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
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