Current Communication Systems Research Articles

Er3+‐Tm3+ Co‐Doped Hybridized Gadolinium Aluminosilicate Glass Fiber for Broadband Optical Amplification

AbstractOptical fiber communication has greatly promoted the development of the information age, while the emergence of 5G networks, cloud computing, and artificial intelligence have put forward high challenges to the capacity of current optical fiber communication systems. At present, increasing the bandwidth of erbium‐doped fiber amplifiers (EDFA) is the most effective way to increase the communication capacity. In this paper, a hybridization strategy is proposed for simultaneous achieving strong and flat optical response and demonstrate the success in construction of Er3+‐Tm3+ co‐doped gadolinium aluminosilicate glass fiber for L‐band optical amplification. Gd3+ ions are introduced to enhance the radiative transition by improving the dispersibility of Er3+. Tm3+ ions are co‐introduced to facilitate energy transfer between Er3+ and Tm3+ for achieving flat emission in the L‐band. The hybridized active fiber which can be effectively fused with quartz fiber is fabricated by melt‐in‐tube (MIT) approach. A fiber amplifier is construed and it enables to achieve a flat on‐off gain (<±0.76 dB) across the L‐band spectrum. These results indicate that Er3+‐Tm3+ co‐doped hybridized gadolinium aluminosilicate glass fiber is a promising gain material for fiber amplifiers and demonstrate that the hybridization approach provides a new strategy for the development of novel active fiber device.

Design and Simulation of Quasi-microstrip Yagi Antenna in Railway Mobile Communication

PROBLEM STATEMENT: The performance and size constraints of the current railway mobile communication systems force the development of more effective communication methods. OBJECTIVES: This study aims to build a quasi-microstrip Yagi antenna with a 900MHz centre frequency that minimizes the antenna's physical dimensions and improves communication capabilities between trains. METHODS: HFSS simulation was used during the design phase to optimize the antenna's characteristics, which included bending the active oscillator to increase gain. Important performance indicators were assessed, including voltage standing wave ratio (VSWR), bandwidth, and return loss. RESULTS: The optimized antenna produced a VSWR of less than 2, a maximum gain of 8.35dB, a bandwidth of 105MHz (spanning from 845MHz to 950MHz), and a return loss of -19.49dB at the centre frequency. According to these results, the antenna satisfies the operating criteria for railway mobile communication. CONCLUSION: The quasi-microstrip Yagi antenna proves useful in engineering applications since it not only meets the communication requirements of railway systems but also shrinks considerably in size compared to conventional Yagi antennas.

Compact diplexer based on SIR feeders, T-shaped resonators, and UIR components for mobile wireless systems

Utilizing T-shaped resonators, Uniform Impedance Resonator (UIR) and Step Impedance Resonator (SIR) feeders, this research presents a new compact microstrip diplexer developed for wireless networks. The diplexer's frequency responses with narrowband features reduce interference and enhance signal integrity, which are critical for current communication systems, and it targets channel frequencies of 3.2 and 4.7 GHz. It exhibits insertion losses of 0.3 and 0.7 dB, return losses of 30 and 19 dB, and isolation between channels surpassing 30 dB, guaranteeing minimum cross-talk and robust signal transmission. Modern mobile environments rely on quick signal processing and data transmission speeds, which are improved by incorporating negative group delay (NGD). The diplexer has been low-profile and suitable for devices with limited space due to its compact design and construction on an FR4 substrate. It is a viable option for mobile communication applications, as confirmed by thorough simulations and experimental validations.

Design of radio communication modules for UAVs using atypical frequencies

The ongoing conflict in Ukraine has demonstrated a significant transformation in warfare, as traditional military strategies are increasingly supplemented by digital technologies, particularly unmanned aerial vehicles (UAVs). This article explores the design of radio communication modules for UAVs operating on non-standard frequencies, addressing the challenges posed by Russian electronic warfare (EW) tactics, which systematically disrupt conventional civilian radio frequencies. By leveraging alternative frequencies, UAVs can maintain reliable communication even in electronically hostile environments. The paper provides an overview of current UAV communication systems, such as ExpressLRS (ELRS), and their limitations in modern combat scenarios. It further details the technical process of designing custom transmitter (TX) and receiver (RX) modules using LoRa (Long Range) technology and components like the LILYGO® TTGO LoRa32 V2 board. Emphasis is placed on the importance of selecting appropriate RF chips, amplifiers, antennas, and filters to optimize performance in frequencies, such as 433 MHz, less affected by electronic warfare. This approach enables the development of robust, adaptive communication systems, offering greater flexibility and independence for UAVs in critical operational contexts. The article concludes by highlighting the potential for further system refinements and future scalability for military use.

Prospects for the development of the communication system and the equipment of special purpose with the regulation of the implementation of measures LTE

Further development of the communication system of the Armed Forces of Ukraine is impossible without the recovery of advanced combat experience and the step-by-step implementation of current communication systems (complexes, equipment) for the highest task to face the Defense Forces of Ukraine. Therefore, the key is not only the selection of new information technologies and current standards in the field of communication, but also the investigation of their implementation in the minds of combatants (as close as possible to the combative ones) of action. Experience in carrying out tasks in the east of Ukraine, especially during offensive (counter-offensive) operations, clearly identifying the problems of securing communications in territories not prepared for communications, as well as in areas where telecommunications infrastructure is completely or partially destroyed. The purpose of this article is to outline the prospects for the development of the communication system and the equipment of special purpose with the understanding of not only theoretical research in radio communications, but also the results of practical research into the effectiveness of system-technical solution based by installed on the local radio station with mobile communication standards 3G and 4G. Based on the results of the research, conclusions and proposals were formed regarding the prospects for further development of the system, including the use of LTE in the communication system of the Armed Forces of Ukraine. The stated propositions are based on the results of the final experience of the assigned possession in the interests of the security of military units (subdivisions) in the Sumy region of Ukraine, as well as on the combat line the focus on the offensive (counter-offensive) actions of the Defense Forces of Ukraine in the east of our State. The presentation material of the article is relevant and necessary for training during the research, aimed at improving the forms and methods of combat stagnation of communication equipment (units), tying the decision to choose necessary communication equipment, as well as the formation of management decisions by military administration bodies to organize (secure) connections in future operations with the release of the immediate occupation of the territories of Ukraine.

Performance Study of FSO/THz Dual-Hop System Based on Cognitive Radio and Energy Harvesting System

In order to address the problems of low spectrum efficiency in current communication systems and extend the lifetime of energy-constrained relay devices, this paper proposes a novel dual-hop free-space optical (FSO) system that integrates cognitive radio (CR) and energy harvesting (EH). In this system, the source node communicates with two users at the terminal via FSO and terahertz (THz) hard-switching links, as well as a multi-antenna relay for non-orthogonal multiple access (NOMA). There is another link whose relay acts as both the power beacon (PB) in the EH system and the primary network (PN) in the CR system, achieving the double function of auxiliary transmission. In addition, based on the three possible practical working scenarios of the system, three different transmit powers of the relay are distinguished, thus enabling three different working modes of the system. Closed-form expressions are derived for the interruption outage probability per user for these three operating scenarios, considering the Gamma–Gamma distribution for the FSO link, the α−μ distribution for the THz link, and the Rayleigh fading distribution for the radio frequency (RF) link. Finally, the numerical results show that this novel system can be adapted to various real-world scenarios and possesses unique advantages.

High-speed 0.22 THz communication system with 84 Gbps for real-time uncompressed 8K video transmission of live events

Terahertz frequency band (0.1 ~ 10 THz) can provide ultra-high transmitting rates for massive emerging applications. However, due to the radio frequency impairments and limited signal processing property of baseband devices, it is difficult for the current terahertz communication systems to be used in real applications. In this work, we report a 0.22 THz communication system, which can provide 84 Gbps air interface rate over 1.26 kilometers distance. Such a system is underpinned by three breakthroughs, namely, integrating the reported terahertz wireless communication system, redesigning the signal processing in baseband devices, and increasing the cut-off frequency and transmitting power of radio frequency component by parameter optimizing. Being applied to realize the real-time transmission of the uncompressed 8K ultra high-definition video in the 31st International University Sports Federation in Chengdu, China, this work is a leaping advancement to enable terahertz systems from experiment to promising applications.

Functional features of well-known means of network shielding

The work briefly reviews the history, types, and capabilities of the main types of firewalls (FW). Firewalls are an important tool for protecting network resources from various information security threats. With the development of technology and the changing nature of attacks, especially those involving artificial intelligence (IoT), firewalls have also evolved, acquiring new functions and capabilities. This work provides a short survey of the main types, and capabilities of firewall technology, providing solutions to issues of comprehensive protection of network equipment and information resources from modern security threats. Different types of firewalls are used depending on the conditions of operation and purpose of the basic information and communication system (ICS), as well as on the place of their (FW) integration into the network or virtual infrastructure of modern information systems. For integrated networks that require a high level of their security, productivity and flexibility, firewalls of the business segment of generation «Next-generation» and «Threat-focused NGFW» are definitely the best choice. Attention was drawn to the fact that mobile firewalls should in every way contribute to the maintenance of resource consensus and eliminate a possible disparity in the performance of networked mobile applications. Adaptability to mobility of current communication systems (Wi-Fi, GSM and others) determines the specificity of security threats for mobile devices and It defines their key feature. This feature is based on permanent readiness for seamless transitions (reconnections) between different networks in conditions of constant energy shortage and limited available computing resources (meaning gadgets). Highlights the main trends, prospects for the development and implementation of different types of firewalls, including the impact of artificial intelligence, machine learning, cloud technologies and the Internet of Things as well as important aspects of their (FW) scope. It is emphasized that the introduction of FW does not replace other security technologies and tools, but effectively expands the existing arsenal of countering new security threats (primarily as an instrument of proactive countermeasures and rapid response to complex network incidents). The article may be useful for students, researchers, and information security professionals who seek to expand their competencies related to the development and operation of modern means of network protection.

Summary of DNS traffic filtering trends as a component of modern information systems security

The study analyzes sources related to methods and technologies for DNS (Domain Name System) traffic filtering. Five main directions are identified that are actively used to enhance security at the DNS level. All examined technologies offer improvements in the quality of DNS filtering. It is emphasized that combining different approaches simultaneously can enhance overall security. The summary of research results on DNS traffic security issues indicates certain problems in the quality of the threat intelligence channels used. Therefore, the implementation of AI and LM technologies should enhance the "depth" of extracting useful information about current threats. It is emphasized that the consideration of information security issues should be conducted exclusively in the context of preventing the disparity of artificial intelligence (AI) capabilities in favor of the adversary (i.e., cybercriminals). Practically, this means that future DNS filtering systems should widely implement the latest advancements in VR, AI, LM, and DL technologies. This is particularly important in countering Domain Generation Algorithm (DGA) mechanisms and the spread of botnets. The specific issues of ensuring a consensus on the security and performance of current information and communication systems when implementing DNS encryption tools are highlighted. The primary problem associated with DNS traffic encryption is the potential for its misuse by attackers to conceal their destructive activities (phishing, spam, etc.).

DEVELOPMENT OF LOW-LATENCY WIRELESS COMMUNICATION SYSTEMS FOR AUTONOMOUS VEHICLES

This research aims to explore the effectiveness of the L3 protocol in improving the V2X communication systems in key performance areas such as low communication delay, high-speed protocols and the effectiveness under real-life conditions. According to the L3 protocol simulation of the research, which employs platforms including COOJA and NS-3, the latency of the networks is lowered compared to that of the conventional DSRC/LTE system at below one millisecond levels adopting the time slots and the capture effect. These challenges observed on other systems such as delays experienced due to high-speed data transfer are addressed in the protocol. The performed measurements prove that the L3 protocol of the system exhibits reliability and scalability depending on the number of vehicles on the road as well as the network load, and retains its workability even with the number of 225 automobiles. These results conform with prior works that underlined the necessity of using sophisticated and low-latency relative communication systems for the usage of an autonomous vehicle network. In doing so, the study shows a future of L3 protocol in enhancing the current V2X communication systems in aspects of low latency, fast data transfer and competency in various conditions. It is suggested that future research include extensive field trials, the increase of security measures, the analysis of the scalability and integration of the new technologies, and the solution of the interoperability issues for the further investigation of the possibilities of the application of the L3 protocol.

Guest Editorial: Unfolding the potential of 5G technologies for future wireless networks

AbstractWith the rapid advancements in mobile Internet and smartphones, data traffic in current mobile communication systems is growing exponentially. At the same time, demands for lower latency, increased robustness, and higher energy efficiency are becoming more stringent. In response, 5G technology promises to meet these demands and is currently garnering extensive research interest from both industry and academia. 5G is not just an incremental improvement over its predecessors; it is a transformative technology designed to revolutionise mobile communications. By offering significantly higher speeds, reduced latency, and the ability to connect a massive number of devices simultaneously, 5G stands to impact a wide range of applications from autonomous vehicles to smart cities, healthcare, and beyond. Significant progress has been made in the standardisation and field deployment of 5G networks. Organisations such as the 3rd Generation Partnership Project (3GPP) have been instrumental in developing the standards that define 5G technologies. Moreover, various pilot projects and commercial deployments have been initiated around the world, showcasing the practical capabilities of 5G in real‐world environments.

Outpatient reception via collaboration between nurses and a large language model: a randomized controlled trial.

Reception is an essential process for patients seeking medical care and a critical component influencing the healthcare experience. However, current communication systems rely mainly on human efforts, which are both labor and knowledge intensive. A promising alternative is to leverage the capabilities of large language models (LLMs) to assist the communication in medical center reception sites. Here we curated a unique dataset comprising 35,418 cases of real-world conversation audio corpus between outpatients and receptionist nurses from 10 reception sites across two medical centers, to develop a site-specific prompt engineering chatbot (SSPEC). The SSPEC efficiently resolved patient queries, with a higher proportion of queries addressed in fewer rounds of queries and responses (Q&Rs; 68.0% ≤2 rounds) compared with nurse-led sessions (50.5% ≤2 rounds) (P = 0.009) across administrative, triaging and primary care concerns. We then established a nurse-SSPEC collaboration model, overseeing the uncertainties encountered during the real-world deployment. In a single-center randomized controlled trial involving 2,164 participants, the primary endpoint indicated that the nurse-SSPEC collaboration model received higher satisfaction feedback from patients (3.91 ± 0.90 versus 3.39 ± 1.15 in the nurse group, P < 0.001). Key secondary outcomes indicated reduced rate of repeated Q&R (3.2% versus 14.4% in the nurse group, P < 0.001) and reduced negative emotions during visits (2.4% versus 7.8% in the nurse group, P < 0.001) and enhanced response quality in terms of integrity (4.37 ± 0.95 versus 3.42 ± 1.22 in the nurse group, P < 0.001), empathy (4.14 ± 0.98 versus 3.27 ± 1.22 in the nurse group, P < 0.001) and readability (3.86 ± 0.95 versus 3.71 ± 1.07 in the nurse group, P = 0.006). Overall, our study supports the feasibility of integrating LLMs into the daily hospital workflow and introduces a paradigm for improving communication that benefits both patients and nurses. Chinese Clinical Trial Registry identifier: ChiCTR2300077245 .

Introduction of a bleepless intern on-call era

BackgroundThe current bleep communication system between nurses and interns on-call in most Irish hospitals has been linked with interruption in patient care, disruption to workflow, inefficiency, increased burden and stress to the on-call health staff. A new electronic system was introduced in a University Hospital to replace and eliminate bleep usage during on-call hours. MethodsAn Intern on-call task electronic template was generated using Microsoft Excel Spreadsheet. This electronic system enabled users to review and respond to requests placed by nursing healthcare staff. This project initially underwent a trial process in three wards for a period of two weeks in June 2023. Interns and nurses were asked to fill a survey before and after introduction of the system. The project was implemented across all wards in August 2023 and a secondary survey was obtained. In addition, the spreadsheets were analysed retrospectively. ResultsDuring the trial, twenty-six interns and twenty nurses were surveyed before and after implementation of the electronic system. Interns satisfaction rate was 73% and stress was reported to be reduced by 65%. Notably, 57% of interns reported a reduction in workload and the number of bleeps was reported to be as <10 by 42%. Nurses reported a decrease in the number of bleeps they needed to send overall by 65% and by 55% for repeated jobs. Workload was reported to be increased by 15% by nurses. However, exactly half of the nurses were unhappy with the new system and stress levels were unchanged. ConclusionThis project has shown promising results, efficient and clear communication was noted with an overall positive feedback and satisfaction rate by doctors. However, as evident, from a nursing perspective further work is needed to further progress into a system that can benefit both parties involved.

Evaluation of Joint Technique Iterative Clipping Filtering (ICF) and Neural Network Predistortion on SDR-based MIMO-OFDM System

Multiple-input, multiple-output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) is a communications technology that powers numerous modern communication systems, including 5G and WiFi-6. This technology is utilized in current communication systems due to its high performance and extensive channel capacity. MIMO-OFDM does have disadvantages, such as large Peak-to-Average Power Ratio (PAPR) values. If the signal is processed by a nonlinear Power Amplifier (PA) device, a high PAPR value signal can result in both in-band and out-of-band signal distortion. To combat high PAPR values, PAPR reduction strategies such as Iterative Clipping Filtering (ICF) are utilized. From this study, using ICF with iteration 2 and Clipping Ratios (CR) 3 and 4 can improve the system's minimum Bit Error Rate (BER) by about 22.8% and 91.1%, respectively. Choosing the correct CR will improve the system, but using the lower CR will make it worse than a system without ICF. This occurs in systems using ICF with iterations two and CR 2 and at the same SNR conditions as systems without ICF; using ICF with iterations two and CR 2 results in higher BER values. The use of Predistortion Neural Network (PDNN) can overcome this problem. By using PDNN, there is an improvement in the system where the minimum BER value can reach 0.1 × 10-5. The percentage decrease in BER from using PDNN for ICF with iterations two and CR 2, 3, and 4 is 99.88%, 99.86%, and 98.807%, respectively. Thus, the joint techniques of ICF and PDNN can significantly enhance the performance of MIMO-OFDM systems with nonlinear PA. Importantly, the experiment was conducted on an SDR device, ensuring the real-world applicability of the results.

Computer‐aided experimental studies for adaptive beamforming algorithms and array processing in engineering education

AbstractSmart antenna and digital antenna systems are considered as a crucial technology for current and future communication systems supporting 5G/6G and nonterrestrial‐networks communications. Based on the information of the received signal/s, smart antenna systems toward the radiation pattern to the desired direction/s. This technique is known as adaptive beamforming. The theories and the applications of adaptive beamforming are taught in engineering educational courses. This paper proposes a set of real‐time interactive experiments for adaptive beamforming algorithms in antenna array processing subject. The proposed experiments can be performed with the computer‐aided experimental studies tool prepared in the MATLAB® environment. The users can easily make comparisons and can perform trade‐offs between different types of adaptive beamforming algorithms, scenarios, and antenna architecture. This is used as a teaching tool for a graduate course on adaptive beamforming algorithms.

Enhancing Data Protection through Advanced Encryption or Improving Data Security with Advanced Encryption

The protection of information content is becoming a key concern with the recent exponential growth of digital data interchange over computer networks. Numerous security vulnerabilities can readily jeopardize the information sent over a network. An enhanced modification for the Advanced Encryption Standard (AES) algorithm is proposed and implemented using an additional key that generated using a linear feedback shift register (LFSR), which provides an efficient technique to pseudo random number generation and also reduces the number of rounds. Cryptography plays a crucial role in ensuring the security of digital data transmission over these unsafe networks. When compared to the original AES algorithm result, the suggested technique produces the expected results for several data types, including text, images, It is more important than ever to strengthen data protection procedures in an era of rising cyber dangers and growing reliance on digital data. A thorough framework for "Enhancing Data Protection through Advanced Encryption" (EDPAE) is introduced in this study. The project's goal is to protect sensitive data by utilizing state-of-the-art encryption techniques in response to the ever-changing cyber security scenario. In addition, the project places a strong emphasis on how to seamlessly incorporate advanced encryption into current data storage and communication systems in order to minimize interference with user operations and greatly improve overall security posture. In order to guarantee the secure creation, distribution, and storage of encryption keys and to reduce potential risks related to key compromise, key management features are addressed.

A broadband transparent antenna applied in indoor mobile communication system

AbstractThis paper proposes a broadband optical transparent antenna using a transparent conductor film on a transparent polyethylene terephthalate (PET) substrate. The planar wide‐slot antenna coupling fed by microstrip has a wide impedance bandwidth, so it is selected to design the transparent antenna. The upper surface of the PET substrate is a microstrip line with a fork‐shaped tuning branch, and the lower surface is a wide slot. They were made of transparent conductor film. Finally, a new capacitive coupling method is used to feed the transparent antenna. The transparent conductor film used in the antenna is metal mesh, which was developed by 3M company. The metal mesh with an open area greater than 80% to achieve high transmittance. The measured results show that the impedance bandwidth is 177% (0.30–5.0 GHz), and the gain of the antenna varies from 5.06 to 7.8 dBi over the entire frequency band. Therefore, it can be well applied to the current indoor mobile communication system.

Miniaturized Lens Antenna with Enhanced Gain and Dual-Focusing for Millimeter-Wave Radar System.

This paper presents a waveguide Lens antenna at the W-band adopting dual-focusing Lens to improve the performance. The Lens antenna consisted of a waveguide slotted structure and lenses processed using NOA73 meet the demands of miniaturization for current communication systems. The antenna radome fabricated using NOA73 not only protects the antenna structure but also improves the gain of the antenna by about 9.5 dBi via electromagnetic wave dual-focusing. A prototype is fabricated using novel UV-LIGA technology. Measured results are compared with simulated values. Measured results confirmed the fabricated antenna operated in the W-band with a 10 dB fractional bandwidth (FBW) of 6.5% from 97.5 to 104 GHz and a peak gain of 22 dBi at 100 GHz in the direction perpendicular to the plane of the feed waveguide. A good agreement between simulation and measurement is obtained, demonstrating efficient radiations in the operating band.

A Novel Wideband Splitter for a Four-Element Antenna Array

In the paper, a novel design of a wideband power splitter for a four-element antenna array using two RF antiphase segments is proposed. Based on a detailed analysis of the power splitter circuit, an analytical model was set up in the MATLAB environment. The derived analytical model allows the development of a design of the described structure for any operating frequency and estimates the properties of the designed structure. In addition to the RF electrical part, the copper cover is also considered in this study. The copper cover serves as both a support and shielding part of the proposed structure. The electrical part consists of two sections of transmission lines. The first transmission line is symmetrical, while the second transmission line is asymmetrical. The given transmission lines can be realized using any technology (microstrip, coaxial, etc.). A prototype of the proposed wideband splitter operating at 650 MHz with a fractional bandwidth of 84.3% was designed and tested in real-world conditions to prove the concept. The board of the manufactured prototype has dimensions of 25 × 152 mm. A double-sided FR4 material with a substrate height of 1.48 mm, copper thickness of 50μm, and ϵr ≅ 4.3, with a dielectric loss tangent of 0.021 was used to manufacture the prototype. The prototype was tested and its parameters were verified in practical conditions as a part of the current radio communication system for the 5G band. Under these conditions, verification measurements of the proposed splitter with a four-element antenna array were carried out.

A Review of Over-the-Air Testing Methods for Performance Measurement of Antennas and Devices in Communication Systems

With the fast development of communication techniques, over-the-air testing has developed into the main testing method for current communication systems due to its advantages including no cable connection, high measurement efficiency, and independence from environment. OTA testing has become almost the only solution for 5G system testing especially after the popularity of 5G massive multiple-input-multiple-output. In this paper, we summarize the three main methods of OTA testing including the reverberation chamber-based method, the radiation two-step method, and the multiprobe anechoic chamber- (MPAC-) based method, among which we focus on the MPAC method systematically. In the MPAC method, there are two main channel synthesis techniques that have been heavily studied, namely, prefaded signal synthesis and plane wave synthesis. We summarize the current main research based on these two techniques including probe configurations, probe selection algorithms, and probe design based on the PFS technique and the design of plane wave generators based on PWS technique. The main comparisons are made for the performance of different probe selection algorithms and the performance of different plane wave generators as well as the latest advances.