The concept of physical layer security builds on the pivotal idea turning channel's imperfections, such as noise and fading, into a source security. This is established through appropriately designed coding techniques signal processing strategies. In this vein, it has been shown that fading channels can enhance transmission confidential information secure communication be achieved even when channel to eavesdropper better than main channel. However, fully benefit from what offer, knowledge...

A spectrum-sharing communication system where the secondary user is aware of instantaneous channel-state information (CSI) link but knows only statistics and an estimated version transmitter-primary receiver investigated. The optimum power profile ergodic capacity are derived for general fading channels [with a continuous probability density function (pdf)] under average peak transmit constraints with respect to following two different interference constraints: 1) outage constraint 2)...

We study the achievable rate of an uplink MIMO cognitive radio system where primary user (PU) and secondary (SU) aim to communicate closest base station (BS) via a multi-access channel through same unmanned aerial vehicle (UAV) relay. The SU message is then forwarded from BS network with certain incentive reward as part cooperation protocol between both networks. A special linear precoding scheme proposed enable exploit PU free eigenmodes. analyze two scenarios in which UAV relay gain matrix...

Device-to-device (D2D) communications underlying the cellular infrastructure are a technology that have been proposed recently as promising solution to enhance network capabilities. It improves spectrum utilization, overall throughput, and energy efficiency while enabling new peer-to-peer location-based applications services. However, interference is major challenge, since same resources shared by both systems. Therefore, management techniques required keep under control. In this paper, in...

The capacity of the intensity-modulation direct-detection optical broadcast channel (OBC) is investigated, under both average and peak intensity constraints. An outer bound on region derived by adapting Bergmans' approach to OBC. Inner bounds are using superposition coding with either truncated-Gaussian (TG) distributions or discrete distributions. While distribution achieves higher rates, TG leads a simpler representation achievable rate region. At high signal-to-noise ratio (SNR), it shown...

Multi-channel (MC) optical wireless communication (OWC) systems employing wave-division multiplexing for outdoors free-space communications, or multi-user time-division multiple access indoors visible-light e.g., can be modeled as parallel channels. Multi-input multi-output OWC also transformed, possibly with some performance loss, to channels using pre-/post-coding. Studying the of such MC-OWC requires characterizing capacity underlying In this paper, upper and lower bounds on constant a...

Motivated by the fact that moments of received signal are easy to compute and can provide a simple way automatically classify modulation transmitted signal, we propose hybrid method for automatic classification lies in intersection between likelihood-based feature-based classifiers. Specifically, proposed relies on statistical along with maximum likelihood engine. We show offers good trade-off accuracy complexity relative classifier. Furthermore, our classifier outperforms state-of-the-art...

Optical wireless communication (OWC) using intensity-modulation and direct-detection (IM/DD) has a channel model which possesses unique features, due to the constraints imposed on input. The aim of this tutorial is overview results capacity IM/DD channels with input-independent Gaussian noise as OWC channels. It provides reader an entry point topic, highlights some major contributions in area. begins discussion models how comes about, addition explanation input constraints. Then, it...

We study the secrecy capacity of multiple- input single-output (MISO) Gaussian wiretap visible light communication (VLC) channel. a typical VLC scenario with one transmitter, legitimate receiver, and eavesdropper. Specifically, we compute achievable rate for various signaling distributions, including truncated generalized normal (TGN) uniform distributions. The transmitter is equipped multiple sources, while unauthorized receivers are each single photodetector. analyze rates via transmit...

We study the deployment of unmanned aerial vehicles (UAV) based cognitive system in an area covered by primary network (PN). An UAV shares spectrum PN and aims to maximize its energy efficiency (EE) optimizing transmit power. focus on case where simultaneously communicates with ground receiver (G), under interference limitation, another relaying (A), a minimal required rate. analytically develop power allocation framework that maximizes EE subject budget, interference, rate constraints. In...

In this paper, two resource allocation schemes for energy efficient cognitive radio systems are proposed. Our design considers approaches that adopt spectrum sharing combined with soft-sensing information, adaptive sensing thresholds, and power to achieve an system. An per good-bit metric is considered as objective function. A multi-carrier system, such as, orthogonal frequency division multiplexing, in the framework. The proposed schemes, using different approaches, designated sub-optimal...

In this paper we study the problem of securing a visible light communication (VLC) link against passive eavesdropping, with help (friendly) jammer. Differently from radio frequency (RF) communications, VLC imposes peak amplitude constraint on input distribution which renders Gaussian inputs not admissible. We provide an achievable secrecy rate that improves upon recently established one in concurrent work by Mostafa and Lampe. Our scheme follows both capacity result Wyner artificial noise...

We consider a status update system consisting of one source, server, and sink. The source generates packets according to Poisson process the are served generally distributed service time. with capacity packet, i.e., there is no waiting buffer in system, model it as an M/G/1/1 queueing system. introduce probabilistically preemptive packet management policy calculate moment generating functions (MGFs) age information (AoI) peak AoI (PAoI) under policy. According policy, when arrives, possible...

We consider a spectrum sharing communication scenario in which primary and secondary users are communicating, simultaneously, with their respective destinations using the same frequency carrier. Both optimal power profile ergodic capacity derived for fading channels, under an average transmit instantaneous interference outage constraints. Unlike previous studies, we assume that user has noisy version of cross link Channel State Information (CSI). After deriving this case, provide...

This paper investigates the secrecy performance of multiple-input single-output visible light communication (VLC) wiretap channel. The considered system model comprises three nodes: a transmitter (Alice) equipped with multiple fixtures LEDs, legitimate receiver (Bob), and an eavesdropper (Eve), each one photo-diode. VLC channel is modeled as real-valued amplitude-constrained Gaussian Eve assumed to be randomly located in same area Bob. Due this, artificial noise-based beamforming adopted...

The capacity of the intensity modulation direct detection multiple-input-multiple-output channel is studied. Therein, nonnegativity constraint transmit signal limits applicability classical schemes, including precoding. Thus, new ways are required for deriving bounds this channel. To end, lower developed in paper by achievable rates two precoding-free schemes: inversion and orthogonal-upper triangular matrix product decomposition. rate a dc-offset singular-value decomposition-based scheme...

In this paper, we study the ergodic capacity of free space optical communication systems over Gamma-Gamma atmospheric turbulence fading channels with perfect channel state information at both transmitter and receiver. our framework, mainly focus on low signal-to-noise ratio range show that scales proportionally to SNR log <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> (1/SNR). We also one-bit CSI feedback is enough achieve using an...

We present a power allocation framework for spectrum sharing cognitive radio (CR) systems based on maximizing the energy efficiency (EE). First, we show that relation between EE and spectral (SE) is strictly increasing in contrast with SE-EE tradeoff discussed literature. also solve nonconvex problem explicitly derive optimal proposed average under either peak or an constraint. apply our results to underlay CR where limited by additional interference When instantaneous channel not available,...

We study the secrecy capacity of fast fading channels under imperfect main channel (between transmitter and legitimate receiver) estimation at transmitter. Lower upper bounds on ergodic are derived for a class independent identically distributed (i.i.d.) channels. The achievable rate follows from standard wiretap code in which simple on-off power control is employed along with Gaussian input. bound obtained using an appropriate correlation scheme eavesdropper best known so far. lower...

When designing wireless communication systems (WCS), the spectral efficiency (SE) has been main design performance metric. Recently, energy (EE) is attracting a huge interest due to massive deployment of power limited WCS such as IoT devices, and stringent environmental concerns. For this reason, many works in literature focused on optimizing EE highlighted EE-SE relationship trade-off (meaning that increasing one decreases other). In article, after introducing metric, we highlight new...

The capacity of flat Rayleigh fading channels with full channel state information (CSI) at the transmitter and receiver asymptotically low SNR has been recently shown to scale essentially as log(1/SNR). In this paper, we investigate Nakagami-m CSI, show that scales Ω/m log (1/SNR), where m is parameter Ω mean-square. We also one-bit CSI enough achieve asymptotic using an On-Off power control scheme. Our framework may be seen a generalization previous works it captures special case by taking = 1.

We study the secret message capacity of an ergodic block fading wiretap channel with partial state information at transmitter and perfect receivers, under both a short term power constraint (STPC) long (LTPC). consider that in addition to statistics main eavesdropper (CSI), sender is provided by legitimate receiver q-bit feedback, beginning each coherence block, through error-free public channel, q bits. establish upper lower bounds on secrecy capacity. show coincide asymptotically as → ∞....

Visible light communication (VLC) is an effective alternative technology to overcome the limitations related radio frequency (RF) spectrum. In modern day of systems, energy harvesting (EH) technique considered as a promising design more efficient systems. Integrating VLC with EH in wireless networks guaranties reliability these networks. this paper, we consider dual-hop VLC/RF communication, composed two Light Emitting Diodes (LEDs) and receivers, assisted by decode-and-forward (DF) relaying...

We investigate the spectral efficiency gain of an uplink cognitive radio (CR) multi-input-multi-output system in which secondary user (SU) is allowed to share spectrum with primary (PU) using a specific precoding scheme communicate common receiver. The proposed exploits, at same time, free eigenmodes channel after space alignment procedure and interference threshold tolerated by PU. At receiver, we adopt successive cancellation (SIC) technique eliminate effect detected signal transmitted...

In order to fill the gap of mathematical analysis's lack for secrecy outage probability (SOP) over single-input multiple-output (SIMO) α-μ wiretap fading channels, this letter initially provides highly accurate and asymptotic closed-form expressions SOP. The novel formulations are derived in a simple general form terms bivariate Fox's H-function, which is extensively used literature. addition, analysis SOP at high signal-to-noise ratio regime. obtained numerically validated compared with...