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This paper investigates dual-hop Reconfigurable Intelligent Surface (RIS) wireless communication systems with malicious jamming, where the destination node faces jamming from a malicious jammer with a RIS-Equipped Unmanned Aerial Vehicle (UAV) relay. We model the channel gains for Tx-RIS and Jammer-RIS links with a Rician distribution, while the RIS-Rx link follows a Nakagami-m distribution, and the jamming status is modeled as a Bernoulli-distributed random variable. We derived and provided closed-form expressions for the probability density functions (PDFs) of the legitimate channel and jamming channel in RIS-Equipped UAV wireless communication systems. Additionally, a new closed-form expression for the PDF of the received signal-to-jamming ratio (SJR) is derived. Using the Gauss–Laguerre Approximation method, we calculate the Average Bit Error Rate (ABER) under Binary Phase Shift Keying (BPSK) and Quadrature Amplitude Modulation (QAM) schemes. We analyze the effects of jamming probability, the location of the legitimate RIS, and different channel conditions on ABER performance through theoretical analyses and simulation results. Our theoretical analyses and simulation results indicate that an increase in the probability of malicious jamming significantly raises the ABER. For example, under favorable channel conditions, the ABER for BPSK modulation was observed to be as low as 10 − 5 , whereas under poor channel conditions, the ABER increased to 10 − 2 . Additionally, by reducing the distance between the transmitter and the RIS, the ABER can be improved. The legitimate RIS performs better when closer to the transmitter. These findings highlight the critical impact of channel conditions and the deployment of the RIS on the overall system's performance. Our results offer valuable insights into designing and evaluating the performance of RIS-Equipped UAV wireless communication systems in the presence of malicious jamming, aiding in the development of countermeasures to enhance system resilience and security. The derived expressions are validated through Monte Carlo simulations. [ABSTRACT FROM AUTHOR]

Wireless communication systems demand efficient solutions, and non-orthogonal multiple access (NOMA) has emerged as a promising approach. The present investigation compares NOMA against orthogonal multiple access (OMA) methods, specifically focusing on TDMA. Through an analysis of the performance metrics, specific optimal power coefficients were derived, ensuring superior performance of NOMA schemes. It is important to note that these optimal power coefficients are dependent on the channel coefficients, meaning they will vary as the channel conditions of the users change. Using copula functions, we modeled the dependence between the channel coefficients and successfully obtained the dependences among the fading coefficients. Utilizing specific optimal power coefficients, calculations for the average secrecy rates of NOMA were conducted, considering the modeled dependencies. The analysis of mathematical and numerical results in this study reveals a significant performance improvement in the average secrecy rates of Downlink NOMA when considering dependent channel coefficients and optimal specific coefficients, as compared to independent NOMA.

Machine learning (ML) algorithms have been widely used to improve the performance of telecommunications systems, including reconfigurable intelligent surface (RIS)-assisted wireless communication systems. The RIS can be considered a key part of the backbone of sixth-generation (6G) communication mainly due to its electromagnetic properties for controlling the propagation of the signals in the wireless channel. The ML-optimized (RIS)-assisted wireless communication systems can be an effective alternative to mitigate the degradation suffered by the signal in the wireless channel, providing significant advantages in the system's performance. However, the variety of approaches, system configurations, and channel conditions make it difficult to determine the best technique or group of techniques for effectively implementing an optimal solution. This paper presents a comprehensive review of the reported frameworks in the literature that apply ML and RISs to improve the overall performance of the wireless communication system. This paper compares the ML strategies that can be used to address the RIS-assisted system design. The systems are classified according to the ML method, the databases used, the implementation complexity, and the reported performance gains. Finally, we shed light on the challenges and opportunities in designing and implementing future RIS-assisted wireless communication systems based on ML strategies. [ABSTRACT FROM AUTHOR]

With the advent of fifth Generation of cellular communication with its key features that superior over all the precedent generations. However, there are some challenges need to be taken into consideration. The main crucial part of communication system is the receiver and as it is known there are two main types of receivers which can be used to demodulate the signals and recover the transmitted data. In this paper, we used those two types of algorithm receivers which are the Non-Coherent and Coherent receivers. They are firstly demonstrated in details in accordance with receiver specification design and then moved to the practical side of implementation. In which novelty of our work is highlighted, by carrying out those different algorithms on the ADSP 21364 SHARC board where initially sampling the received DPSK signal, design the Bandpass and lowpass digital filtering respectively and all to be compiled by Analog Devices VisualDSP + + software that is programmed by C language prior to download to the ADSP Board chip. The same algorithm is followed in the frame synchronization for both of them by detecting the message through distinguishing the preamble of the message " + + + + " data which is before the 72 bytes (real message).Then that actual message will be stored and dumped to the memory and displayed to ensure from the received message whether it is corrupted with errors or not. However, it is clearly noticed that the Coherent receiver is more efficient than the Non-coherent, but it still a bit expensive because used double look-up tables for cosine and sine in IQ converter. Finally, coherent receiver with Costas loop algorithm was implemented as well to improve the previous differential detection scheme. [ABSTRACT FROM AUTHOR]

Fifth generation (5G) mobile communication systems have been deployed in the millimeter wave (mmWave) band. Since electromagnetic (EM) waves in this band exhibit high propagation loss and antennas are highly directive, the performance of wireless communications is largely degraded in a non-line-of-sight (NLOS) area, resulting in a limited coverage area. To improve the performance and increase the coverage area, a metamaterial-based electromagnetic scattering sheet (EMSS) with broad scattering characteristics is proposed in this paper. We also introduce fast design and optimization methods using equivalent circuits of metamaterials, antenna array theory, and the genetic algorithm (GA). The diffusion coefficient is used as a fitness value to evaluate the scattering characteristics of the EMSS generated by GA. The broad scattering characteristics of the designed EMSS are experimentally confirmed. We clarified that the optimized EMSS has a higher diffusion coefficient than a metal plate of the same size. Finally, we demonstrated improved wireless communication performance in an NLOS area by diffusing the incoming EM fields using our designed EMSS.

Wireless communication systems demand efficient solutions, and non-orthogonal multiple access (NOMA) has emerged as a promising approach. The present investigation compares NOMA against orthogonal multiple access (OMA) methods, specifically focusing on TDMA. Through an analysis of the faformance metrics, specific optimal power coefficients were derived, ensuring sufaior faformance of NOMA schemes. It is important to note that these optimal power coefficients are dependent on the channel coefficients, meaning they will vary as the channel conditions of the users change. Using copula functions, we modeled the dependence between the channel coefficients and successfully obtained the dependences among the fading coefficients. Utilizing specific optimal power coefficients, calculations for the average secrecy rates of NOMA were conducted, considering the modeled dependencies. The analysis of mathematical and numerical results in this study reveals a significant faformance improvement in the average secrecy rates of Downlink NOMA when considering dependent channel coefficients and optimal specific coefficients, as compared to independent NOMA. [ABSTRACT FROM AUTHOR]

Summary: Microstrip patch antennas (MPA) are widely used in wireless communication systems due to their ease of manufacture, low cost, and low profile. This work proposes a proximity‐coupled rectangular microstrip patch antenna array (PRMPA) adaptable for 5G applications. However, the existing research works suffered from low gain, low efficiency, and narrow bandwidth. In addition, 5G communications suffer from path loss in high‐frequency bands. For managing this issue, the large gain antenna is essential. Hence, this research aims to design and fabricate high‐gain compact 2 × 2 slotted PRMPA for 5G applications. The antenna design is simulated on HFSS and operates at 28–37 GHz. Here, the antenna parameters like length, width, and feed line parameters are optimized using a metaheuristic optimization like the mayfly optimizer (MFO). Further, a circular‐shaped metamaterial split‐ring resonator (SRR) reduces the mutual coupling. Then, Rogers RT5880 is used as substrate material, and the design operates at 34.5 GHz. The gain and radiation efficiency achieved by the proposed antenna design are 15.4 dB and 94.4% for the simulated outcomes. Highlights: This research aims to introduce a compact 2 × 2 proximity‐coupled rectangular microstrip patch antenna (PRMPA) array for 5G communications at 28–37 GHz bands.This study's aim is to introduce a metaheuristic algorithm mayfly optimizer (MFO) to optimize the antenna's dimensions (length and width).This study provides the slots in a corner on both sides of the antenna to improve the gain and efficiency.This research aims to demonstrate the parameters of designed antennas, like single element and 2 × 2 array; they are compared based on gain, bandwidth, voltage standing wave ratio (VSWR), reflection coefficient, and radiation efficiency. [ABSTRACT FROM AUTHOR]

Secured broadband radio communications are becoming increasingly pivotal for high-speed connectivity in radio access networks, playing a crucial role in both mobile information systems and wireless IoT connections. This paper introduces a chaos-based two-channel digital radio communication system utilizing fiber optic radio transmission technology. The system comprises two radio channels operating at up to 1 Gbps using amplitude shift keying (ASK) modulation, followed by modulation with a chaotic sequence before conversion to the optical domain using the MZM modulator. To compensate for fiber loss, the system utilizes an Erbium-Doped Fiber Amplifier (EDFA) and employs the optical links through standard ITU-G.655 optical fibers. Numerical simulation of the designed system is performed using the commercialized simulation software Optisystem V.15 to assess and characterize transmission performance. The results demonstrate the system's effective operation on two channels with a fiber transmission distance of up to 110 km, maintaining a bit error ratio of less than 10-9. This feature ensures reliable performance for high-speed radio connections, particularly in applications such as fronthaul networks in cloud radio access and wireless sensor network connections. [ABSTRACT FROM AUTHOR]

In a wireless communication chain, filters play a critical role in ensuring the efficiency, reliability, and overall performance of the system. In fact, filters are essential for selecting specific frequency bands. They can narrow or widen the bandwidth, depending on the requirements of the communication protocol. Appropriate bandwidth management is crucial for optimizing data transmission rates and accommodating multiple channels within the available spectrum. This article describes the design of a compact bandpass filter with two identical rectangular open-loop resonators. The proposed filter frequency response covers the 3.5 GHz global interoperability for microwave access (WiMAX) and fifth generation (5G) applications. The structure of this filter uses the Rogers RO6010 substrate, which has a dielectric constant of 10.2, thickness of 1.27 mm, and tangent loss of 0.0023. The proposed device is intended for wireless communication systems operating at 3.5 GHz. The filter offers a wide bandwidth of 1.21 GHz with a small size of (5.72 × 12.34) mm2, and a low insertion loss of −0.16 dB. The suggested filter offers effective utilization across various applications including fifth-generation (5G), sub-6G, and WiMAX. Simulation and optimization of the proposed design are conducted utilizing the HFSS (High Frequency Structure Simulator) software. To corroborate the results from HFSS, the ADS (Advanced Design System) software is employed. The simulation outcomes obtained from both HFSS and ADS simulators demonstrate close resemblance.

This paper is devoted to dynamic network flows. A phenomenon called dynamic network flow splash is studied (splash is an exceeding of flow value over maximum feasible static flow for the same network). Parallel and tree-structured network topology classes are defined. Conditions for occurring network flow splash in the parallel and tree-structured networks are discovered. A formula for computing a value of maximum dynamic network flow splash is obtained. An algorithm for calculating the formula values is presented., Author(s): I. M. Erusalimskiy [sup.1], V. A. Rusakov [sup.1] Author Affiliations: (1) https://ror.org/01tv9ph92, grid.182798.d, 0000 0001 2172 8170, Institute of Mathematics, Mechanics and Computer Science, Southern Federal University, , 8a [...]