Reconfigurable intelligent surfaces (RISs) have the potential of realizing emerging concept smart radio environments by leveraging unique properties metamaterials and large arrays inexpensive antennas. In this article, we discuss applications RISs in wireless networks that operate at high-frequency bands, e.g., millimeter wave (30-100 GHz) sub-millimeter (greater than 100 frequencies. When used networks, may a manner similar to relays. The present paper, therefore, elaborates on key...

Deep learning based on artificial neural networks (ANNs) is a powerful machine-learning method that, in recent years, has been successfully used to realize tasks such as image classification, speech recognition, and language translation, among others, that are usually simple for human beings but extremely difficult machines. This one reason deep considered of the main enablers realizing intelligence (AI). The current methodology consists employing data-driven approach identify best...

Reconfigurable intelligent surfaces have emerged as a promising technology for future wireless networks. Given that large number of reflecting elements is typically used and the surface has no signal processing capabilities, major challenge to cope with overhead required estimate channel state information report optimized phase shifts surface. This issue not been addressed by previous works, which do explicitly consider during resource allocation phase. work aims at filling this gap,...

We consider a fading channel in which multiantenna transmitter communicates with multi-antenna receiver through reconfigurable intelligent surface (RIS) that is made of N passive scatterers impaired by phase noise. The beamforming vector at the transmitter, combining receiver, and shifts are optimized order to maximize signal-to-noise-ratio (SNR) receiver. By assuming Rayleigh (or line-of-sight propagation) on transmitter-RIS link RIS-receiver link, we prove SNR random variable equivalent...

We introduce algorithms for optimizing a single-input single-output reconfigurable intelligent surface (RIS) assisted system. The RIS is modeled by using an electromagnetic-compliant framework based on mutual impedances and its reconfigurability realized through tunable lumped impedances. In the absence of coupling among scattering elements RIS, we derive closed-form expression optimal impedances, which accounts interplay between amplitude phase loads RIS. presence coupling, iterative...

We study a multi-user multiple-input multiple-output interference network in the presence of multiple reconfigurable intelligent surfaces (RISs). The entire system is described by using circuit-based model for transmitters, receivers, and RISs. This obtained leveraging electromagnetic tool mutual impedances, which accounts signal propagation coupling among closely-spaced scattering elements. An iterative provably convergent optimization algorithm that maximizes sum-rate RIS-assisted channels...

Reconfigurable intelligent surfaces (RISs) have the potential of realizing emerging concept smart radio environments by leveraging unique properties meta-surfaces. In this article, we discuss applications RISs in wireless networks that operate at high-frequency bands, e.g., millimeter wave (30-100 GHz) and sub-millimeter (greater than 100 frequencies. When used networks, may a manner similar to relays. This paper elaborates on key differences similarities between are configured as anomalous...

Reconfigurable intelligent surface (RIS) is a disruptive technology to enhance the performance of physical-layer key generation (PKG) thanks its ability smartly customize radio environments. Existing RIS-assisted PKG methods are mainly based on idealistic assumption an independent and identically distributed (i.i.d.) channel model at both base station (BS) RIS. However, i.i.d. inaccurate for typical RIS in isotropic scattering environment neglecting existence spatial correlation would...

The design of communication systems typically relies on the development mathematical models that describe underlying channel. In many systems, however, accurate channel may not be known, or enough even available for efficient system design. these scenarios, a completely new approach to and analysis is required. An example such situations arises in emerging research field molecular communications, which it very difficult develop analytical several operating scenarios. this context, use...

In this paper, we consider a molecular communication system that is made of 3D unbounded diffusion channel model without flow, point transmitter, and spherical absorbing receiver. particular, study the impact inter-symbol interference analyze performance different threshold-based receiver schemes. The aim paper to optimize receivers by using conventional model-based approach, which relies on an accurate system, emerging data-driven which, other hand, does not need any apriori information...

Reconfigurable intelligent surface (RIS) is a promising technique to enhance the performance of physical-layer key generation (PKG) due its ability smartly customize radio environments. Existing RIS-assisted PKG methods are mainly based on idealistic assumption an independent and identically distributed (i.i.d.) channel model at both transmitter RIS. However, i.i.d. inaccurate for typical RIS in isotropic scattering environment. Also, neglecting existence spatial correlation would degrade...

We consider a reconfigurable intelligent surface (RIS) assisted multiple-input multiple-output (MIMO) system in the presence of scattering objects. The MIMO transmitter and receiver, RIS, objects are modeled as mutually coupled thin wires connected to load impedances. introduce novel numerical algorithm for optimizing tunable loads which does not utilize Neumann series approximation. is provably convergent, has polynomial complexity with number RIS elements, outperforms most relevant...

Visible light communication (VLC) system based on orthogonal frequency division multiplexing (OFDM) is promising for its ability to link a huge number of devices with high reliability and low latency. However, OFDM‐based VLC systems are very sensitive the symbol timing offsets. Thus, synchronisation algorithm important system. In this study, authors first propose zero correlation code pair (ZCC pair) investigate periodical impulse‐shaped property ZCC pair. Then novel offset estimation The...

:In January 2011, a revolutionary movement fighting for political democracy broke out in Egypt, influenced by the Jasmine Revolution that had taken place Tunisia. With development of Revolution, democratic gave way to an unexpected Islamic movement, represented Muslim Brotherhood which has received broad civil support. In most recent national presidential election on June 23rd - 24th, Mursi, chairman The Freedom and Justice Party Shafiq, former Prime Minister, became candidates second round...

Deep learning based on artificial neural networks is a powerful machine method that, in the last few years, has been successfully used to realize tasks, e.g., image classification, speech recognition, translation of languages, etc., that are usually simple execute by human beings but extremely difficult perform machines. This one reasons why deep considered be main enablers notion intelligence. In order identify best architecture an network allows fit input-output data pairs, current...

In this paper, we consider non-coherent detection schemes for molecular communication systems in the presence of inter-symbol-interference. particular, study detectors based on memory-bits-based thresholds order to achieve low bit-error-ratio (BER) transmission. The main challenge realizing is obtain channel state information only received signals. We tackle issue by reformulating through intermediate variables, which can be obtained clustering multi-dimensional data from signals, and using...

Reconfigurable intelligent surfaces (RISs) are a promising technology for enhancing the communication performance of future wireless systems by controlling environment. In addition, dynamic metasurface antennas (DMAs) increasing number antenna elements multiple-input multiple-output (MIMO) at reduced cost and power consumption compared to conventional MIMO arrays. this paper, we amalgamate these two technologies in order realize massive networks with superior complexity. We first introduce...

To facilitate the development of asymmetrically clipped optical orthogonal frequency division multiplexing systems, a joint synchronization and channel estimation scheme is proposed. The preamble used in based on zero correlation code pair has impulse-like relationship. This property can let results process be coarsely estimated time response, thus simplifies response generation. Also, transceiver with low complexity proposed needs only half amount multiplications compared conventional...

The filter bank multicarrier with offset quadrature amplitude modulation (FBMC-OQAM) has aroused widespread concern in the 5G communication. However, FBMC-OQAM an inherent drawback of high peak-to-average power ratio (PAPR) that should be mitigated. Here, authors propose efficient hybrid scheme based on sparse partial transmit sequence (sparse PTS) and tone reservation (TR) to reduce PAPR systems. first step is detect record location peak signals adopt phase rotation factors (based directly...

In order to mitigate bandwidth attenuation of diffusion link visible light communication systems caused by multipath effects, we present an optical orthogonal frequency division multiplexing channel estimation scheme based on compressed sensing (CS) and signal parameters via rotational invariance techniques (ESPRIT). First, derived a parametric model. Then, used ESPRIT obtain parameters. After that, built dynamic over-complete dictionary that can be in CS processing. Finally, reconstructed...

We consider a fading channel in which multi-antenna transmitter communicates with receiver through reconfigurable intelligent surface (RIS) that is made of $N$ passive scatterers impaired by phase noise. The beamforming vector at the transmitter, combining receiver, and shifts are optimized order to maximize signal-to-noise-ratio (SNR) receiver. By assuming Rayleigh (or line-of-sight propagation) on transmitter-RIS link RIS-receiver link, we prove SNR random variable equivalent distribution...

In this paper, we study surface-based communication systems based on different levels of channel state information for system optimization. We analyze the performance in terms rate and degrees freedom (DoF). show that deployment a reconfigurable intelligent surface (RIS) results increasing number DoF, by extending near-field region. Over Rician fading channels, an RIS can be efficiently optimized only positions transmitting receiving surfaces, while providing good if factor is not too small.