Intelligent reflecting surfaces (IRSs) have the potential to transform wireless communication channels into smart reconfigurable propagation environments. To realize this new paradigm, passive IRSs be large, especially for in far-field scenarios, so that they can compensate large end-to-end path-loss, which is caused by multiplication of individual path-losses transmitter-to-IRS and IRS-to-receiver channels. However, optimizing a number sub-wavelength IRS elements imposes significant...

Molecular communication (MC) is a new engineering paradigm where molecules are employed as information carriers. MC systems expected to enable revolutionary applications, such sensing of target substances in biotechnology, smart drug delivery medicine, and monitoring oil pipelines or chemical reactors industrial settings. As for any other kind communication, simple yet sufficiently accurate channel models needed the design, analysis, efficient operation systems. In this paper, we provide...

Intelligent reflecting surfaces (IRSs) have been introduced into wireless communications systems due to their great potential smartly customize and reconfigure radio propagation environments in a cost-effective manner. Despite the promising advantages of IRSs, academic research on IRSs is still its infancy. In particular, design analysis IRS-assisted communication critically depend accurate tractable modeling IRS. this article, we first present compare three IRS models, namely conventional...

In molecular communication (MC) systems, the expected number of molecules observed at receiver over time after instantaneous release by transmitter is referred to as channel impulse response (CIR). Knowledge CIR needed for design detection and equalization schemes. this paper, we present a training-based estimation framework MC which aims estimating based on due emission sequence known numbers transmitter. Thereby, distinguish two scenarios depending whether or not statistical knowledge...

Simple and easy to implement testbeds are needed further advance molecular communication research. To this end, paper presents an in-vessel testbed using magnetic nanoparticles dispersed in aqueous suspension as they also used for drug targeting biotechnology. The transmitter is realized by electronic pump injection via a Y-connector. A second provides background flow signal propagation. For reception, we employ susceptometer, device including coil, where the particles move through generate...

Hybrid radio frequency (RF)/free space optical (FSO) systems are among the candidate enabling technologies for next generation of wireless networks, since they benefit from both high data rates FSO subsystem and reliability RF subsystem. In this paper, we focus on problem throughput maximization in parallel hybrid RF/FSO relay channel. channel, a source node sends its to destination with help multiple nodes. Thereby, given relay, source-relay relay-destination links orthogonal respect each...

This article considers the resource allocation algorithm design for downlink multiple-input single-output (MISO) orthogonal frequency division multiple access (OFDMA) ultra-reliable low latency communication (URLLC) systems. To meet stringent delay requirements of URLLC, short packet transmission is adopted and taken into account design. The optimized maximization weighted system sum throughput subject to quality-of-service (QoS) constraints regarding URLLC users' number transmitted bits,...

In this paper, we consider a cascaded radio frequency (RF) and hybrid RF/free space optical (FSO) system where several mobile users transmit their data over an RF link to decode-and-forward relay node (e.g., small cell base station) the forwards information destination macro-cell RF/FSO backhaul link. The employ multiple antennas for transmission reception links while each user has single antenna. are orthogonal FSO but half-duplex with respect other, i.e., either user-relay or...

In this paper, we investigate the statistics of free space optics (FSO) communication channel between a hovering unmanned aerial vehicle (UAV) and central unit. Two unique characteristics make UAV-based FSO systems significantly different from conventional with static transceivers. First, for systems, incident laser beam is not always orthogonal to receiver lens plane. Second, both position orientation UAV fluctuate over time due dynamic wind load, inherent random air fluctuations in...

The influence of overall particle shape, mean size, initial relative density and effective normal stress on the global local soil–geosynthetic interaction is investigated here through an extensive series direct shear interface tests between six sands in contact with one multifilament woven geotextile, non-woven geotextile geomembrane. Analysis data highlights mobilisation higher peak friction angles increases angularity sand particles decrease stress. average frictional efficiencies...

Free-space optical (FSO) systems are able to offer the high data-rate, secure, and cost-efficient communication links required for applications such as wireless front- backhauling 5G 6G networks. Despite substantial advancement of FSO over past decades, requirement a line-of-sight connection between transmitter receiver remains key limiting factor their deployment. In this article, we discuss potential role intelligent reflecting surfaces (IRSs) solution relax requirement. We present an...

In this paper, we study two novel massive multiple-input multiple-output (MIMO) transmitter architectures for millimeter wave (mmWave) communications which comprise few active antennas, each equipped with a dedicated radio frequency (RF) chain, that illuminate nearby large intelligent reflecting/transmitting surface (IRS/ITS). The IRS (ITS) consists of number low-cost and energy-efficient passive antenna elements are able to reflect (transmit) phase-shifted version the incident...

In this paper, we study the optimal resource allocation algorithm design for large intelligent reflecting surface (IRS)-assisted simultaneous wireless information and power transfer (SWIPT) systems. To facilitate efficient system IRSs, instead of jointly optimizing all IRS elements, partition into several tiles employ a scalable optimization framework comprising an offline stage online stage. stage, elements each tile are designed to support set different phase shift configurations, referred...

Most algorithms developed for the optimization of Intelligent Reflecting Surfaces (IRSs) so far require knowledge full Channel State Information (CSI). However, resulting acquisition overhead constitutes a major bottleneck realization IRS-assisted wireless systems in practice. In contrast, this letter, focusing on downlink transmissions from Base Station (BS) to Mobile User (MU) that is located blockage region, we propose optimize IRS illumination area centered around MU. Hence, proposed...

This letter introduces a formalism for modeling time-variant channels diffusive molecular communication systems. In particular, we consider fluid environment where one transmitter nano-machine and receiver are subjected to Brownian motion in addition the of information molecules used communication. Due stochastic movements nano-machines, statistics channel impulse response change over time. We show that behaviour can be accurately captured by appropriately modifying diffusion coefficient...

Although many exciting applications of molecular communication (MC) systems are envisioned to be at microscale, the MC testbeds reported in literature so far mostly macroscale. This may partially due fact that controlling an system microscale is challenging. To link macroworld microworld, we propose and demonstrate a biological signal conversion interface can also seen as modulator. In particular, proposed transduces optical signal, which controlled using light-emitting diode, into chemical...

This is the second part of a two-part paper considering bidirectional relay networks with half-duplex nodes and block fading where transmit fixed transmission rate. In Part I, it was shown that considerable gain in terms sum throughput can be obtained by optimally selecting modes or, equivalently, states nodes, i.e., transmit, receive, silent states, based on qualities involved links. To enable adaptive mode selection, has to equipped two buffers for storage data received from users. The...

In this paper, we consider mobile molecular communication (MC) systems which are expected to find application in several fields including targeted drug delivery and health monitoring. We develop a mathematical framework for modeling the time-variant stochastic channels of diffusive MC systems. particular, system consisting pair transmitter receiver nano-machines suspended fluid medium with uniform bulk flow, where assume that either or both mobile, model mobility by Brownian motion. The...

In this paper, we propose using mobile nanosensors (MNSs) for early stage anomaly detection. For concreteness, focus on the detection of cancer cells located in a particular region blood vessel. These produce and emit special molecules, so-called biomarkers, which are symptomatic presence anomaly, into cardiovascular system. Detection biomarkers with conventional tests is difficult stages due to very low concentration samples taken. However, close cells, high. Hence, possible if sensor...

Unmanned aerial vehicle (UAV)-based communications is a promising new technology that can add wide range of capabilities to the current network infrastructure. Given flexibility, cost-efficiency, and convenient use UAVs, they be deployed as temporary base stations (BSs) for on-demand situations like BS overloading or natural disasters. In this work, UAV-based communication system with radio frequency (RF) access links mobile users (MUs) free-space optical (FSO) backhaul link ground station...

Synthetic molecular communication (MC) is a new engineering paradigm which expected to enable revolutionary applications such as smart drug delivery and real-time health monitoring. The design implementation of synthetic MC systems (MCSs) at nano- microscale very challenging. This particularly true for MCSs employing biological components transmitters receivers or interfaces with natural MCSs. Nevertheless, since have been optimized by nature over billions years, using them in highly...

In this letter, we focus on large intelligent reflecting surfaces (IRSs) and propose a new codebook construction method to obtain set of predesigned phase-shift configurations for the IRS unit cells. Since overhead channel estimation complexity online optimization IRS-assisted communications scale with size codebook, design small codebooks is high importance. We show that there exists fundamental tradeoff between power efficiency codebook. first analyze baseline designs employ linear across...

This paper investigates the resource allocation algorithm design for intelligent reflecting surface (IRS) aided multiple-input single-output (MISO) orthogonal frequency division multiple access (OFDMA) multicell networks, Where a set of base stations cooperate to serve ultra-reliable loiv-latency communication (URLLC) users. The IRS is deployed enhance channel and increase reliability by creating virtual line sight URLLC users With unfavorable propagation conditions. first study on...

In this paper, we investigate the modeling and design of intelligent reflecting surface (IRS)-assisted optical communication systems, which can circumvent line-of-sight (LOS) requirement in multi-link free space (FSO) systems. The FSO laser beams incident on IRSs have a Gaussian power intensity profile nonlinear phase profile, whereas plane waves radio frequency (RF) systems uniform linear profile. Given these substantial differences, results available for IRS-assisted RF are not applicable...

In this paper, we present a low overhead beam management approach for near-field millimeter-wave multi-antenna communication systems enabled by Reconfigurable Intelligent Surfaces (RISs). We devise novel variable-width hierarchical phase-shift codebook suitable both the near- and far-field of RIS, fast alignment algorithm RIS phase shifts transceiver beamformers. Indicative performance evaluation results are shown, verifying effectiveness proposed in comparison with various benchmark schemes.