Indoor millimeter-wave (mmWave) environment channels are typically sparsely-scattered and dominated by a strong line-of-sight (LOS) path. Therefore, communication over such is in general extremely difficult when the LOS path not present. However, recent introduction of reconfigurable intelligent surfaces (RISs), which have potential to influence propagation controlled manner, has change previous paradigm. Motivated this, we study channel capacity optimization utilizing RISs indoor mmWave...

Reconfigurable intelligent surfaces (RISs) represent a new technology that can shape the radio wave propagation in wireless networks and offers great variety of possible performance implementation gains. Motivated by this, we study achievable rate optimization for multi-stream multiple-input multiple-output (MIMO) systems equipped with an RIS, formulate joint problem covariance matrix transmitted signal RIS elements. To solve this problem, propose iterative algorithm is based on projected...

In this paper, we study the capacity and symbol error probability (SEP) of generalized spatial modulation (GSM) multiple-input multiple-output (MIMO) using measured channels that are obtained by channel sounding in an indoor office environment at 60GHz. Spatial (SM) GSM emerging low-complexity MIMO schemes have been extensively researched for low-GHz (below 6GHz) communications. Recently, they considered shown to be promising also (mmWave) simplest possible case, require only one RF chain...

Receive spatial modulation (RSM) is a recently introduced multi-antenna transmission scheme that capable of achieving high spectral efficiency at low hardware and processing complexity. We study RSM for application in indoor line-of-sight (LOS) millimeter-wave (mmWave) communication. Significantly different from low-gigahertz channels, which are typically modeled by Rician distribution, mmWave channels sparsely-scattered dominated LOS propagation. Hence, we consider the specific...

Reconfigurable intelligent surfaces (RISs) represent a new technology that can shape the radio wave propagation and thus offer great variety of possible performance implementation gains. Motivated by this, we investigate achievable sum-rate optimization in broadcast channel (BC) presence RISs. We solve this problem exploiting well-known duality between Gaussian multiple-input multiple-output (MIMO) BC multiple-access (MAC), correspondingly derive three algorithms which optimize users'...

We investigate the achievable rate (AR) of a stacked intelligent metasurface (SIM)-aided holographic multiple-input multiple-output (HMIMO) system by jointly optimizing SIM phase shifts and power allocation. Contrary to earlier studies suggesting that AR decreases when number layers increases past certain point for \emph{a fixed thickness}, our findings demonstrate consistent increase. To achieve this, we introduce two problem formulations: one based on directly maximizing (RMax) other...

The main difficulty concerning optimizing the mutual information (MI) in reconfigurable intelligent surface (RIS)-aided communication systems with discrete signaling is inability to formulate this optimization problem an analytically tractable manner. Therefore, we propose use cutoff rate (CR) as a more metric for MI and introduce two methods maximize CR, assuming perfect knowledge of channel state (CSI). first method based on projected gradient (PGM), while second derived from principles...

Reconfigurable intelligent surfaces (RISs) represent a promising candidate for sixth-generation (6G) wireless networks, as the RIS technology provides new solution to control propagation channel in order improve efficiency of link through enhancing received signal power. In this paper, we propose RIS-assisted receive quadrature space shift keying (RIS-RQSSK), which enhances spectral an RIS-based index modulation (IM) system by using real and imaginary dimensions independently purpose IM....

Accurate channel estimation is essential for achieving the performance gains offered by reconfigurable intelligent surface (RIS)-aided wireless communications. A variety of methods have been proposed such systems; however, none existing takes into account effect synchronization errors as carrier frequency offset (CFO). In general, CFO can significantly degrade orthogonal division multiplexing (OFDM) systems. Motivated this, we investigate on RIS-aided OFDM Furthermore, propose a joint and...

Accurate channel estimation is essential to achieve the performance gains promised by use of reconfigurable intelligent surfaces (RISs) in wireless communications. In uplink multi-user orthogonal frequency division multiple access (OFDMA) systems, synchronization errors such as carrier offsets (CFOs) can significantly degrade performance. This becomes more critical RIS-aided communications, RIS phases are adjusted based on estimates and even a small error leads significant loss. Motivated...

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...

Spatial modulation (SM) and generalized spatial (GSM) are emerging multiple input output (MIMO) schemes that use transmitter (TX) antenna switching for data transmission. Their operating principle makes optimization of channel capacity mutual information usually more difficult than conventional MIMO which not based on switching. We propose to cut-off rate as a relevant tractable metric performance (SM)/GSM systems, it constitutes practical lower-bound capacity. In particular, we four TX...

In this paper we consider Generalized Pre-coding aided Spatial Modulation (GPSM), which was recently proposed as a promising alternative to conventional Multiple Input Output (MIMO) transmission schemes. GPSM only part of the receive antennas is activated with aid pre- coding at transmitter. Hence, information bits are mapped spatial symbol, corresponding particular activation pattern, and modulation symbols. Optimal performance achieved Maximum Likelihood (ML) detector, but its exhaustive...

Reconfigurable intelligent surfaces (RISs) represent a new technology that can shape the radio wave propagation and thus offers great variety of possible performance implementation gains. Motivated by this, we investigate achievable sum-rate optimization in broadcast channel (BC) is equipped with an RIS. We exploit well-known duality between Gaussian multiple-input multiple-output (MIMO) BC multiple-access (MAC) to derive alternating (AO) algorithm which jointly optimizes users' covariance...

In this paper Minimum Mean Square Error (MMSE) precoding for the Preprocessing aided Spatial Modulation (PSM) transmission scheme is investigated. PSM capable to transmit data both in spatial domain and modulation domain. We derive upper bound Average Bit Probability (ABEP) MMSE precoded we show by means of simulations that tight a large signal noise ratio (SNR) range. Also, influence number receive antennas on ABEP analyzed. It shown increase will improve ABEP. demonstrated analytical...

Reconfigurable intelligent surfaces (RISs) have huge potential to improve spectral and energy efficiency in future wireless systems at a minimal cost. However, early prototype results indicate that deploying hundreds or thousands of reflective elements is necessary for significant performance gains. Motivated by this, our study focuses on \emph{large-scale } RIS-assisted multi-user (MU) multiple-input multiple-output (MIMO) systems. In this context, we propose an efficient algorithm jointly...

One of possible ways RSA cryptoalgorithm with a very long key implementation, besides most commonly used Montgomery's algorithm, is shift and carry algorithm. In this paper FPGA implementation algorithm presented, where 1024 bits long. Appropriate VHDL model for was written. Project synthesis results (resource occupancy maximal operating frequency), as well software hardware testing are shown. Brief comparison project implementations based on stated at the end.

In the context of emerging stacked intelligent metasurface (SIM)-based holographic MIMO (HMIMO) systems, a fundamental problem is to study mutual information (MI) between transmitted and received signals establish their capacity. However, direct optimization or analytical evaluation MI, particularly for discrete signaling, often intractable. To address this challenge, we adopt channel cutoff rate (CR) as an alternative metric MI maximization. regard, propose alternating projected gradient...

Stacked intelligent metasurface (SIM), which consists of multiple layers metasurfaces, is emerging as a promising solution for future wireless communication systems. In this timely context, we focus on broadcast multiple-input multiple-output (MIMO) systems and aim to characterize their energy efficiency (EE) performance. To gain comprehensive understanding the potential SIM, consider both dirty paper coding (DPC) linear precoding formulate corresponding EE maximization problems. For DPC,...

Dynamic metasurface antennas (DMAs) are an alternative application of metasurfaces as active reconfigurable with advanced analog signal processing and beamforming capabilities, which have been proposed to replace conventional antenna arrays for next generation transceivers. Motivated by this, we investigate the bit error probability (BEP) optimization in a DMA-based system, propose iterative algorithm, adjusts transmit precoder weights DMA elements, prove its convergence derive complexity.