This work focuses on the downlink of a single-cell multi-user system in which base station (BS) equipped with M antennas communicates K single-antenna users through reconfigurable intelligent surface (RIS) installed line-of-sight (LoS) BS. RIS is envisioned to offer unprecedented spectral efficiency gains by utilizing N passive reflecting elements that induce phase shifts impinging electromagnetic waves smartly reconfigure signal propagation environment. We study minimum...

The concept of reconfiguring wireless propagation environments using intelligent reflecting surfaces (IRS)s has recently emerged, where an IRS comprises a large number passive elements that can smartly reflect the impinging electromagnetic waves for performance enhancement. Previous works have shown promising gains assuming availability perfect channel state information (CSI) at base station (BS) and IRS, which is impractical due to nature elements. This paper makes one preliminary...

The challenge of wildfire management and detection is recently gaining increased attention due to the severity frequency wildfires worldwide. Popular fire techniques, such as satellite imaging remote camera-based sensing suffer from late low reliability while early a key prevent massive fires. In this article, we propose novel solution based on unmanned aerial vehicles assisted Internet Things (UAV-IoT) networks. main objective to: 1) study performance UAV-IoT networks for 2) present...

The capacity of the free-space optical channel is studied. A new recursive approach for bounding based on sphere-packing proposed. This leads to upper bounds a with peak intensity constraint or an average constraint. Under only, derived bound tighter than existing earlier by Farid and Hranilovic. achievable rate truncated-Gaussian input distribution also derived. It shown that under both constraints, this are within small gap at high SNR, leading simple high-SNR approximation. Simple fitting...

A network model is considered, where Poisson distributed base stations transmit to N power-domain nonorthogonal multiple access (NOMA) users (TIEs) each that employ successive interference cancellation (SIC) for decoding. We propose three models the clustering of NOMA TIEs and consider two different ordering techniques TIEs: mean signal power-based instantaneous signal-to-intercell-interference-and-noise-ratio-based. For technique, we present a signal-to-interference-and-noise ratio analysis...

The recently completed 5G new radio standard is a result of several cutting-edge technologies, including massive multiple-input multiple-output (MIMO), millimeter (mm)-Wave communication and network densification. However, these technologies face two main practical limitations 1) the lack control over wireless channel, 2) high power consumption interface. To address need for green sustainable future cellular networks, concept reconfiguring propagation environments using Intelligent...

Intelligent reflecting surfaces (IRS) can improve the physical layer security (PLS) by providing a controllable wireless environment. In this paper, we propose novel PLS technique with help of IRS implemented an intelligent mirror array for visible light communication (VLC) system. First, aided VLC system containing access point (AP), legitimate user and eavesdropper, channel gain lower bound achievable secrecy rate are derived. Further, to enhance while restricting formulate maximization...

Federated learning (FL) has emerged as a distributed machine (ML) technique to train models without sharing users' private data. In this paper, we introduce decentralized FL scheme that is called federated empowered overlapped clustering for aggregation (FL-EOCD). The introduced FL-EOCD leverages device-to-device (D2D) communications and enable aggregation, where cluster defined coverage zone of typical device. devices located on the clusters are bridge (BDs). proposed scheme, topology...

Non-orthogonal multiple access (NOMA) is promoted as a key component of 5G cellular networks. As the name implies, NOMA operation introduces intracell interference (i.e., arising within cell) to operation. The managed by careful design (e.g., user clustering and resource allocation) along with successive cancellation. However, most proposed designs are agnostic intercell from outside cell), which major performance limiting parameter in This paper sheds light on drastic negativeimpact...

A demonstration of ultraviolet-B (UVB) communication link is implemented utilizing quadrature amplitude modulation (QAM) orthogonal frequency-division multiplexing (OFDM).The based on a 294-nm UVB-light-emitting-diode (UVB-LED) with full-width at half-maximum (FWHM) 9 nm and light output power 190 μW, 7 V, special silica gel lens top it.A -3-dB bandwidth 29 MHz was measured high-speed near-solar-blind data rate 71 Mbit/s achieved using 8-QAM-OFDM perfect alignment.23.6 2-QAM-OFDM when the...

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...

Visible light communications (VLCs), in general, and resource allocation for VLC networks particular, have gained lots of attention recently. In this paper, we consider the problem a downlink transmission system employing dynamic time division multiple access, where power variables are tuned to maximize spectral efficiency (SE). As operational conditions, impose constraints on average optical intensity, energy budget, quality-of-service. To solve non-convex problem, transform objective...

For circumventing the alignment requirement of line-of-sight (LOS) underwater wireless optical communication (UWOC), we demonstrated a non-line-of-sight (NLOS) UWOC link adequately enhanced using ultraviolet (UV) 375-nm laser. Path loss was chosen as figure-of-merit for performance in this investigation, which considers effects geometries, water turbidity, and transmission wavelength. The experiments suggest that path decreases with smaller azimuth angles, higher shorter wavelength due part...

Cloud-radio access networks (C-RAN) help in overcoming the scarcity of radio resources by enabling dense deployment base-stations (BSs) and connecting them to a central-processor (CP). This paper considers downlink C-RAN, where cloud is connected BSs via limited-capacity backhaul links. We propose optimize C-RAN transmission scheme that combines rate splitting, common message decoding, beamforming vectors design clustering. To this end, optimizes splitting (RS), decoding (CMD), clustering...

While intelligent reflecting surface (IRS) assisted wireless communication has emerged as an important research paradigm, channel state information (CSI) acquisition remains a critical challenge to design the IRS phase-shifts and yield promised coherent beamforming gains. In this letter, we propose IRS-assisted opportunistic (OBF) scheme under proportional fair scheduling, which does not require instantaneous CSI parameters. slow-fading environment, show that with only random rotations at...

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...

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...

In this paper, we consider and study a cell-free massive MIMO (CF-mMIMO) system aided with reconfigurable intelligent surfaces (RISs), where large number of access points (APs) cooperate to serve smaller users the help RIS technology. We imperfect channel state information (CSI), each AP uses local estimates obtained from uplink pilots applies conjugate beamforming for downlink data transmission. Additionally, random at during both training transmission phases. This allows us eliminate need...

Federated Learning (FL) has emerged as a significant paradigm for training machine learning models. This is due to its data-privacy-preserving property and efficient exploitation of distributed computational resources. achieved by conducting the process in parallel at users. However, traditional FL strategies grapple with difficulties evaluating quality received models, handling unbalanced reducing impact detrimental To resolve these problems, we introduce novel federated framework, which...