Performance Of Wireless Communication Research Articles

Cell PCI Assignment Method Based on Particle Swarm Optimization

In order to streamline PCI allocation within cells for diminished conflicts, interferences, and complexities, an innovative methodology is introduced. A novel approach employing Particle Swarm Optimization (PSO) is employed to gauge and enhance cellular performance in wireless communications. We developed a comprehensive database for 2067 active cells along with their collision, interference, and confusion matrices. Utilizing regression tree models to analyze the influence of PCI configurations on MR values, coupled with PSO's capacity to refine PCI configurations, significantly reduces MR values, consequently boosting network performance. This study exemplifies the effective integration of machine learning and optimization algorithms into enhancing wireless network efficiency, offering network operators a valuable decision-making tool in intricate scenarios.

Statistical channel modeling for low-elevation in LEO satellite communication

Channel modeling plays a crucial role in measuring wireless communication performance. This paper describes statistical channel modeling for a recorded signal from a ground station in an urban area in Tehran. This signal was recorded from the GRBALPHA satellite at 170–180° elevation and fixed azimuth. The three-state Markov channel modeling is used for this case. Markov models are often used for Land Mobile Satellite Channels (LMSC) because when the user is moving at different speeds between different environments, this causes, Variety in received power. By analyzing the communication channel in the lower elevations, the link budget can be designed with a suitable margin by considering the channel specification and its limitations. In addition to increasing communication time, reducing the bit error rate (BER), lowering costs, etc., this causes a more accurate channel analysis from the beginning to the end of the satellite passage.This work presents a statistical model for channel simulation using the Markov multi-state chain, estimating the Markov channel model between a fixed ground station and a Low Earth Orbit (LEO) Satellite at low elevations. The comparison of simulation data with recorded data demonstrates the proposed approach's effectiveness in modeling the channel.

Orthogonal waveform-based backscattering interference suppression technique for underwater optical wireless communication

The backscattering effects degrade the detection performance in a full-duplex underwater optical wireless communication (UOWC) system when the power of received backscattering interference is comparable to that of a target signal. In this paper, the orthogonal waveforms with the Hermite–Gaussian function and prolate spheroidal wave function are first introduced for a pulse position modulation based dynamic UOWC system to alleviate the backscattering effects. Then, a joint maximum likelihood detection scheme is proposed accordingly. Experimental results verify the superiority of the proposed method with orthogonal waveforms over the scheme without orthogonal pulse shaping in a dynamic underwater bubbly channel.

BPSK based MIMO with heterodyne detection for enhancing optical wireless communication performance under effect of atmospheric turbulence and pointing errors

BPSK based MIMO with heterodyne detection for enhancing optical wireless communication performance under effect of atmospheric turbulence and pointing errors

Security and Trust in the 6G Era: Risks and Mitigations

The ubiquitous diffusion of connected devices in every context of the daily life of citizens, public bodies, and companies is stimulating the creation of new applications that require very high wireless communication performances. To fulfill this need, the sixth generation of communication standards (6G) is planned to roll out by 2030. While structuring this new standard, it is crucial to take into account the security aspects given the impact of the technologies that will rely on its reliability and resiliency. In this paper, we provide an overview of the technologies that will be used in 6G to achieve the required functional goals for the development of key applications. Then, we proceed to discuss the threats and the solutions to make the communications infrastructure secure and reliable, and finally, we elaborate on the concept of how to achieve trust in this scenario.

Performance analysis of an underwater wireless optical communication link with Lommel beam

In order to mitigate the stochastic interference of underwater channels and improve the quality of underwater communication systems, it is essential to study the performance of the underwater wireless optical communication (UWOC) links utilizing vortex beams with unique attributes. In this paper, the analytical formulae for the bit error rate (BER) and the average capacity of the UWOC link with diffraction-free Lommel beam are derived under the Rytov theory. Simulation results demonstrate that the system with a long wavelength, a high system signal-to-noise ratio(SNR), a small asymmetric parameter and receiving aperture diameter achieves a high average capacity and a low BER. Furthermore, in the underwater channel with a larger kinetic energy dissipation rate per unit mass of fluid and inner scale, a smaller mean-squared temperature dissipation rate, temperature salinity contribution ratio and transmission distance, the performance of the communication link can be improved. Meanwhile, it is found that the performance of the link with carrier Lommel beam are less sensitive to the topological charge, the scaling factor of the beam and the turbulent outer scale. These findings provide theoretical support for the design and implementation of an UWOC link utilizing the Lommel beam.

Modulation effect of focusing mirror on beam propagation through anisotropic turbulence

In this study, we modulated the Bessel-Gaussian (BG) beam using a focusing mirror to enhance the performance of wireless optical communication (WOC) while considering the angles between turbulence cells and the transmitted direction when beams propagate through anisotropic atmospheric turbulence along a slant path. Numerical results reveal that when the BG beam is modulated by a focusing mirror with a focusing length of 1 km, the detection probability of orbital angular momentum (OAM) is increased by 9.06% compared with the unmodulated BG beam when the OAM quantum number is 1. Simultaneously, this modulation method effectively reduces the bit error rate and enhances the channel capacity in OAM-based WOC. Furthermore, we observed that the smaller the OAM number, the better the effect of the modulation. Through our analysis, we identified that the most significant distortions in OAM mode propagation occur at the exponential parameter approximately 3.1 in the modified von Karman spectrum. Moreover, we demonstrated that the effects of the anisotropic tilt angle can not be negligible for beams through a slant path. Therefore, the modulation of the focusing mirror, in combination with a well-designed propagation direction that takes appropriate angles into account, can significantly improve the overall quality and performance of optical communication systems.

The Impact of Using DPSK Modulation on the Performance of Transdermal Optical Wireless Communications under Pointing Errors

The current paper explores the impact of misalignment between transceivers (referred to as pointing error (PE)) on the performance of transdermal optical wireless (TOW) technology, as indicated by average signal-to-noise ratio (SNR), outage probability (OP), outage rate (OR), and average ergodic capacity (AEC). This study was inspired by the effectiveness of differential phase shift keying (DPSK) in enhancing the reliability of the link in free-space optical communications (FSO). Furthermore, this enhancement was studied and analyzed in consideration of the impact of pointing errors. In particular, this paper presents a mathematical analysis that considers certain characteristics of the channel, limitations within the body, the pointing errors (PEs) between the transceivers, and other specific aspects of the optical unit. The results demonstrate the significant impact of PEs on the reliability of the TOW link and highlight the improvement provided by the DPSK technique. i.e., 3 dB better performance compared to the on-off keying (OOK) modulation technique. Finally, this research demonstrates the practical application of wireless optical technology in the medical field within the wavelength range of 800–1300 nm, with optimal performance observed around 1100 nm.

Performance analysis of OSSK-UWOC systems considering pointing errors and channel estimation errors.

In this paper, we present the bit error rate (BER) performance of the underwater wireless optical communication (UWOC) systems using the optical space shift keying (OSSK) on the gamma-gamma turbulent fading channel, which also considers pointing errors and channel estimation errors. Firstly, we develop the new expressions for the probability density function (PDF) based on the Gamma-Gamma distribution with error factors. Subsequently, we analyze the statistical characteristic of the difference in attenuation coefficients between two channels in the OSSK system, by which we provide analytical results for evaluating the average BER performance. The results show that the effective improvement of spectral efficiency (SE) and BER performance is achieved by rationally allocating the number of lasers and detectors in the system. The OSSK-UWOC system performs better when a narrow beam waist is used. Furthermore, the presence of channel estimation error brings the BER performance advantage to the system, and the system with a high channel estimation error (ρ = 0.7) shows a 4 dB improvement in signal-to-noise ratio (SNR) gain compared to the system with a low channel estimation error (ρ = 0.95). The findings in this paper can be used for the UWOC system design.

A compact dual band hexagon rectangular shaped monopole antenna for WIMAX and WLAN applications

This paper presents a compact dual-band hexagon-rectangular shaped monopole antenna for WiMAX and WLAN applications. The miniaturized size of the antenna being 29 × 38 × 0.8 mm3. The proposed antenna operates efficiently within two distinct frequency ranges: 2.7 GHz to 3.2 GHz and 4.0 GHz to 5.1 GHz, addressing the needs of both WiMAX and WLAN systems. The antenna achieves bandwidths of 16.67% and 25.58% for the respective frequency bands, ensuring reliable performance and wide coverage for high-speed wireless communication. The antenna design attains its nature and application as a result of the center hexagonal shaped cavity which creates the required dual bands.

Optical transparent metasurface lenses and their wireless communication efficiency enhancement

This paper presents the design of an optically transparent metasurface tailored for the 2.4 GHz Wi-Fi band. It is optically transparent and attaches to both sides of the glass to improve communication efficiency. The shape of focusing region is a rectangle with an area of 5 cm by 5 cm and a length of 10 cm. The metasurface attaches to both sides of the glass and realizes area focusing. To meet the requirements for area focusing, the metasurface possesses a double-layer structure of a Jerusalem cross and a circle, and the conductive thin film is a conductive and optically transparent copper mesh. The spatial distribution of field strength in a microwave unreflected chamber is scanned to verify the regional focusing effect of the metasurface. Compared with ordinary glass, the metalens achieves field enhancement of more than 7.3 dB in the designed aggregation region, with an average download speed increasing 20.2 Mb/s. Subsequently, the download speed and network speed stability in different scenarios are tested. The standard deviation is used to calculate the dispersion of the download speed. The results demonstrate that in the focusing area, comparing with ordinary glass, the average download speed of the signal across is increased by 13.8 Mb/s in the indoor environment, accompanied by a reduction in the standard deviation by 0.5. In the stairwell, the average download speed of the signal across of the metalens is observed to increase 12.1 Mb/s, accompanied by a reduction in the standard deviation by 1.4. In conclusion, the metasurface lens demonstrates the better ability to significantly reduce the standard deviation of download speed data in both indoor and stairwell test environments than in air and ordinary glass. This results in the effective smoothing out of the speed uctuations and the enhancing of signal transmission stability. Therefore, the ability of metalens to effectively reduce the amplitude of download speed fluctuations in various indoor environmental contexts confirms its key role in adapting to complex environments and improving the wireless communication performance. Moreover, the download speed of signals passing through the metalens is increased by more than 12 Mb/s in both test environmentsthan that of ordinary glass. This effectively improves not only the signal strength but also the communication efficiency. Concurrently, the designed optically transparent metasurface lens is straightforward in structure and user-friendly, and at the same time, it is moveable and can be positioned according to the needs of communication enhancement. The optically transparent metasurface lens scheme proposed in this study provides a potential solution to the high penetration loss problem currently encountered in indoor wireless communication.

Bitter Rate of Performance in Wireless Communications on 5G Technology

Wireless communications have become an integral part of our modern society, enabling seamless connectivity and data exchange. The bit rate of performance in wireless communication systems plays a crucial role in determining the quality of service and user experience. This abstract provides an overview of key factors influencing bit rate in wireless communications and highlights the challenges and advancements in optimizing performance. The bit rate, often measured in bits per second (bps) or multiples thereof, quantifies the rate at which data can be transmitted over a wireless channel. Several factors impact the bit rate in wireless communications, including the available bandwidth, modulation schemes, signal-to- noise ratio (SNR), and channel conditions. The bit rate is closely related to the achievable data throughput and is a critical metric for assessing the efficiency of wireless networks. Wireless technologies, such as 4G and 5G, have significantly increased the bit rates achievable for mobile communication. These technologies employ advanced modulation techniques and multiple-input, multiple- output (MIMO) systems to enhance spectral efficiency and data rates. Additionally, the deployment of small cells and the use of high-frequency bands have improved data rates and reduced latency in wireless networks. However, challenges persist in optimizing bit rates for wireless communications. Factors like signal interference, fading, and path loss can degrade performance. Moreover, the ever- increasing demand for data-intensive applications and the proliferation of IoT devices put additional pressure on wireless networks to deliver higher bit rates with low latency. To address these challenges, ongoing research focuses on developing advanced signal processing algorithms, beamforming techniques, and error correction mechanisms. Machine learning and artificial intelligence are also being employed to optimize wireless communication systems and enhance bit rates.

Fast Transceiver Design for RIS-Assisted MIMO mmWave Wireless Communications

Due to high bandwidth and small antenna size, millimeter-wave (mmWave) integrated line-of-sight (LOS) multiple-input-multiple-output (MIMO) systems have attracted much attention. Reconfigurable intelligent surfaces (RISs), which have the potential to change the characteristics of incident electromagnetic waves with low power cost, can improve the performance for the MIMO mmWave wireless communications. Uniform circular array (UCA) is an effective antenna structure with low complexity transceiver. In this paper, UCA based RIS-assisted MIMO mmWave wireless communications with transmit UCA, the RIS UCAs, and receive UCA are investigated. Since the rotation angles between the transceiver make the channel matrix noncirculant, an algorithm is developed to derive the ranges of the rotation angles based on an acceptable error and reduce the impact of rotation angles on channel matrix. Then, we propose a low-complexity precoding scheme at the transmitter, phase designs at the RIS UCAs, and a phase compensation scheme at the receiver, which can convert the channel matrix into an equivalent circulant channel matrix with a small error. Then, a fast symbol-wise maximum likelihood (ML) detection scheme is proposed to recover the signals with low computational complexity. Simulation results are presented to illustrate the theory.

Bit error rate performance of underwater optical wireless communication with hybrid modulation

AbstractTurbulence effects can cause performance degradation for underwater optical wireless communication (UOWC) system. In this paper, a hybrid modulation (modulation–modulation, M–M) is presented to resist turbulence‐induced fading and improve the transmission performance of UOWC systems. The proposed differential phase shift keying‐multiple pulse position modulation (DPSK‐mPPM) is adopted as hybrid modulation to improve the bit error rate (BER) performance over UOWC turbulence channel of Gamma–Gamma distribution. Subsequently, the closed‐form average BER expressions of mPPM and hybrid DPSK‐mPPM modulation are derived and investigated, which are related to the oceanic turbulence parameters. The influence of the variation of anisotropy factor of ocean turbulence is analysed for the UOWC system over strong Gamma–Gamma turbulent channels. Finally, the numerical simulation results demonstrate the effectiveness of proposed DPSK‐mPPM to improve the BER performance compared to the traditional single modulation over UOWC channel under the same conditions. Furthermore, the work of this paper improves the practicality of the proposed DPSK‐mPPM scheme for underwater communication in complex oceanic environments.

An Improved GOMP Sparse Channel Estimation for Vehicle-to-Vehicle Communications

Reliable channel estimation is critical for wireless communication performance, especially in vehicle-to-vehicle (V2V) communication scenarios. Aiming at the major challenges of channel tracking and estimating as the highly dynamic nature of vehicle environments, an improved generalized orthogonal matching pursuit (iGOMP) is proposed for V2V channel estimation. The iGOMP algorithm transforms the channel estimation problem into a sparse signal recovery problem and replaces the classical inner product criterion with the Dice atom matching criterion. Additionally, the atomic weak progressive selection method is integrated to avoid the suboptimal selection of atoms from the redundant dictionary using the inner product criterion. The proposed iGOMP method can achieve optimal channel estimation by iterating feedback results. Simulation results demonstrate that the iGOMP method has superior estimation accuracy, mean square error (MSE), and bit error rate (BER) performance compared with traditional channel estimation methods in V2V communications.

A Survey on UAV-Enabled Edge Computing: Resource Management Perspective

Edge computing facilitates low-latency services at the network’s edge by distributing computation, communication, and storage resources within the geographic proximity of mobile and Internet-of-Things devices. The recent advancement in Unmanned Aerial Vehicle (UAV) technologies has opened new opportunities for edge computing in military operations, disaster response, or remote areas where traditional terrestrial networks are limited or unavailable. In such environments, UAVs can be deployed as aerial edge servers or relays to facilitate edge computing services. This form of computing is also known as UAV-enabled Edge Computing (UEC), which offers several unique benefits such as mobility, line-of-sight, flexibility, computational capability, and cost-efficiency. However, the resources on UAVs, edge servers, and Internet-of-Things devices are typically very limited in the context of UEC. Efficient resource management is therefore a critical research challenge in UEC. In this article, we present a survey on the existing research in UEC from the resource management perspective. We identify a conceptual architecture, different types of collaborations, wireless communication models, research directions, key techniques, and performance indicators for resource management in UEC. We also present a taxonomy of resource management in UEC. Finally, we identify and discuss some open research challenges that can stimulate future research directions for resource management in UEC.

A Planar Dual Notched Band Vivaldi Antenna for Wireless Communication Applications

With the aim of realizing a Vivaldi Antenna (VA) with stop bands for wireless communication applications, this paper introduces a novel, uncomplicated, easily fabricated, and compact planar VA featuring two distinctive rejected frequency bands. The designed VA is engraved onto an FR4-epoxy substrate, measuring 0.4243λ0×0.4296λ0 ×0.01315λ0 at 2.63 GHz. The integration of dual notched band functionality is ingeniously achieved through the implementation of a simple additional strip and a U-formed slit. A physical prototype of the VA was successfully constructed and meticulously measured with the R&S®ZNB Vector Network Analyser. The measured impedance bandwidth demonstrates that the realised VA operates from 2.63 GHz to beyond 12 GHz while effectively excluding two bands: 3.46-4.16 GHz (18.37 %) and 5.32-6.5 GHz (19.97 %). Simulated results indicate that the designed VA can provide stable unidirectional radiation patterns, reasonable realized gain, and acceptable radiation efficiency across its operating ranges, with notable drops observed at the two notched bands. As a result, these findings highlight the practical value of the designed VA for wireless communication applications, particularly in scenarios where the integration of filtering structures in antennas becomes essential to prevent interference with co-existing systems. The presented VA opens new avenues for enhancing wireless communication performance, catering to the increasing demand for reliable and interference-resistant solutions.

Multifunctional difluoroboron β-diketonate-based luminescent receiver for a high-speed underwater wireless optical communication system.

The last decade has witnessed considerable progress in underwater wireless optical communication in complex environments, particularly in exploring the deep sea. However, it is difficult to maintain a precise point-to-point reception at all times due to severe turbulence in actual situations. To facilitate efficient data transmission, the color-conversion technique offers a paradigm shift in large-area and omnidirectional light detection, which can effectively alleviate the étendue limit by decoupling the field of view and optical gain. In this work, we investigated a series of difluoroboron β-diketonate fluorophores by measuring their photophysical properties and optical wireless communication performances. The emission colors were tuned from blue to green, and >0.5 Gb/s data transmission was achieved with individual color channel in free space by implementing an orthogonal frequency-division multiplexing (OFDM) modulation scheme. In the underwater experiment, the fluorophore with the highest transmission speed was fabricated into a 4×4 cm2 luminescent concentrator, with the concentrated emission from the edges coupled with an optical fiber array, for large-area photodetection and optical beam tracking. The net data rates of 130 Mb/s and 217 Mb/s were achieved based on nonreturn- to-zero on-off keying and OFDM modulation schemes, respectively. Further, the same device was used to demonstrate the linear light beam tracking function with high accuracy, which is beneficial for sustaining a reliable and stable connection in a dynamic, turbulent underwater environment.

Asymmetric Additive‐Assisted Organic Solar Cells with Much Better Energy Harvesting and Wireless Communication Performance

AbstractOrganic solar cells (OSCs), exhibiting better sensitivity to different light intensities and higher power conversion efficiencies (PCEs) under indoor illumination, have great potential to be simultaneously used for solar energy harvesting and optical communication. However, the poor intrinsic molecular stacking and phase separation in active layers significantly hinder the charge transport and extraction in OSCs for achieving this aim. Here, an effective heterohalogen‐substitution asymmetric additive strategy is proposed to fine‐tune the non‐covalent interaction with nonfullerene molecules and optimize the morphology of active layer, which greatly boosts both the OSC photovoltaic performance with the PCEs of up to 18.30% and 29.52% under AM 1.5G and indoor light illumination respectively, and the ‒3 dB communication bandwidths of 4.11, 3.14, and 3.04 MHz at red, green, and blue (RGB) wavelengths respectively. Of particular note, combining the wavelength division multiplexing and adaptive bit‐loading technologies, the visible light communication system comprised of the RGB light sources and additive‐treated OSCs delivers more remarkable data throughput of 302.7 Mb s−1 and higher harvesting power of 7.38 mW simultaneously, presenting an excellent self‐powered capability for enhanced endurance. This work demonstrates that high‐performance OSCs with excellent energy harvesting and wireless communication capacity can be perfectly achieved by a heterohalogen‐substitution asymmetric additive strategy.

A Survey on STAR-RIS: Use Cases, Recent Advances, and Future Research Challenges

The recent development of metasurfaces, which may enable several use cases by modifying the propagation environment, is anticipated to substantially affect the performance of 6G wireless communications. Metasurface elements can produce passive sub-wavelength scattering to enable a smart radio environment. STAR-RIS, which refers to reconfigurable intelligent surfaces (RIS) that can transmit and reflect concurrently (STAR), is gaining popularity. In contrast to the widely studied RIS, which can only reflect the wireless signal and serve users on the same side as the transmitter, the STAR-RIS can reflect and refract (transmit), enabling 360-degree wireless coverage, thus serving users on both sides of the transmitter. This paper presents a comprehensive review of the STAR-RIS, focusing on the most recent schemes for diverse use cases in 6G networks, resource allocation, and performance evaluation. We begin by laying the foundation for RIS (passive, active, STAR-RIS), and then discuss the STAR-RIS protocols, advantages, and applications. In addition, we categorize the approaches within the domain of use scenarios, which include increasing coverage, enhancing physical layer security (PLS), maximizing sum rate, improving energy efficiency (EE), and reducing interference. Next, we will discuss the various strategies for resource allocation and measures for performance evaluation. We aimed to elaborate, compare, and evaluate the literature regarding setup, channel characteristics, methodology, and objectives. In conclusion, we examine this field’s open research problems and potential future prospects.