Hasil untuk "Cellular telephone services industry. Wireless telephone industry"

A. J. A. Al-Gburi

Enhancing antenna gain remains a key requirement in modern wireless systems, particularly with the rapid evolution of 5G, emerging 6G networks, satellite links, and high-resolution radar. Recent research trends increasingly rely on frequency-selective surfaces (FSSs) and metasurface-based reflectors, which offer precise electromagnetic wave control, beam shaping, and polarization management. However, these advanced structures often require complex unit-cell optimization, tight fabrication tolerances, and higher implementation cost. This situation raises a practical question: Are such sophisticated reflector surfaces always necessary, or can conventional metallic reflectors still provide competitive gain performance in many scenarios? In this review, I critically compare metallic reflectors, FSS reflectors, and metasurface reflectors in terms of gain enhancement, bandwidth behavior, sidelobe control, polarization response, fabrication complexity, and cost-effectiveness. The analysis reveals that while FSS and metasurfaces enable highly controlled and adaptive radiation characteristics, simple metallic reflectors can achieve comparable gain performance in many broadband and cost-sensitive applications. The review also identifies application domains where advanced reflectors are justified—such as adaptive beamforming, spatial filtering, and reconfigurable intelligent surface (RIS) platforms—and those where metallic reflectors offer a more efficient and accessible solution. This study provides practical design insight to help antenna engineers balance performance, complexity, and implementation cost, demonstrating that high gain does not always require high structural complexity.

Yuichi Honjo, Cedric Caremel, Yoshihiro Kawahara et al.

Wireless power transfer has the potential to seamlessly power electronic systems, such as electric vehicles, industrial robots, and mobile devices. However, the leakage magnetic field is a critical bottleneck that limits the transferable power level, and heavy ferromagnetic shields are needed for transferring large amounts of power. In this paper, we propose a ferrite-less coil design that generates an asymmetric magnetic field pattern focused on one side of the resonator, which effectively reduces the leakage magnetic field. The key to enabling the asymmetric field pattern is a coil winding strategy inspired by the Halbach array, a permanent magnet arrangement, which is then tailored for wireless power using an evolutionary strategy algorithm. Numerical analyses and simulations demonstrated that the proposed coil structure delivers the same amount of power as spiral coils, while achieving an 86.6% reduction in magnetic field intensity at a plane located 75 mm away from the resonator pair and a power efficiency of 96.0%. We verified our approach by measuring the power efficiency and magnetic field intensity of a test wireless power system operating at 6.78 MHz. These findings indicate that our approach can efficiently deliver over 50 times more power without increasing magnetic field exposure, making it a promising solution for high-power wireless power transfer applications.

Aygun Baltaci, E. Dinc, Mustafa Ozger et al.

Electrification turned over a new leaf in aviation by introducing new types of aerial vehicles along with new means of transportation. Addressing a plethora of use cases, drones are gaining attention in the industry and increasingly appear in the sky. Emerging concepts of flying taxi enable passengers to be transported over several tens of kilometers. Therefore, unmanned traffic management systems are under development to cope with the complexity of future airspace, thereby resulting in unprecedented communication needs. Moreover, the long-term increase in the number of commercial airplanes pushes the limits of voice-oriented communications, and future options such as single-pilot operations demand robust connectivity. In this survey, we provide a comprehensive review and vision for enabling the connectivity applications of aerial vehicles utilizing current and future communication technologies. We begin by categorizing the connectivity use cases per aerial vehicle and analyzing their connectivity requirements. By reviewing more than 500 related studies, we aim for a comprehensive approach to cover wireless communication technologies, and provide an overview of recent findings from the literature toward the possibilities and challenges of employing the wireless communication standards. After analyzing the proposed network architectures, we list the open-source testbed platforms to facilitate future investigations by researchers. This study helped us observe that while numerous works focused on cellular technologies to enable connectivity for aerial platforms, a single wireless technology is not sufficient to meet the stringent connectivity demands of the aerial use cases, especially for the piloting operations. We identified the need of further investigations on multi-technology heterogeneous network architectures to enable robust and real-time connectivity in the sky. Future works should consider suitable technology combinations to develop unified aerial networks that can meet the diverse quality of service demands of the aerial use cases.

Dipankar Shakya, Theodore S. Rappaport, Davood Shahrjerdi et al.

A new multiuser terahertz (THz) measurement facility, or “THz Lab,” located at the New York University (NYU) wireless research center, develops a next-generation laboratory to enable pioneering research at the upper reaches of the radio spectrum: the sub-THz (100–300 GHz) and THz (0.3–3 THz) frequency bands. The cellular telephone industry’s recent realization of the viability of the millimeter wave (mm-wave) radio spectrum for 5G has created a need for the next-generation measurement platform that can promote foundational research for wireless communications, circuit design, antennas and propagation, and novel materials into the 6G era and beyond [1]. The THz Lab, funded by a US$3 million National Science Foundation (NSF): Major Research Instrumentation (MRI) grant, explores the spectrum frontier at frequencies from the mm-wave and into the THz bands, where material and propagation properties are not well known but which offer great promise for massively wideband channels and yet-to-be-determined capabilities of future cell phones, autonomous vehicles, and smart devices. Since the U.S. Federal Communications Commission authorized using sub-THz frequencies above 95 GHz for the first time in 2019 [2], other countries are also now opening these high-frequency bands. Notably, Ofcom in the United Kingdom and other European nations through the European Union’s Horizon 2020 have begun exploring spectrum sharing and device innovations for applications at the THz frequencies [3], [4]. Similarly, spectrum regulators in Canada and Australia are actively exploring applications and use cases at sub-THz and THz frequencies [5], [6]. The costs and technical challenges to accurately design and repeatably measure devices and radio systems at these frequencies are tremendous. However, little is known about how to best design such systems, let alone characterize them and make them work reliably. The THz Lab enables fundamental explorations of circuits, antennas, radio propagation, and materials at the THz level for applications involving sensing and communications in emerging 6G wireless networks and beyond.

Mingyue Zhang, Guangyu Xu, Renjing Gao

The rapid development of wireless technology has heightened the requirement for antenna performance. Traditional antennas, characterized by their static performance, are no longer sufficient to accommodate the dynamic requirements of modern wireless systems. The advent of reconfigurable antennas has opened new horizons for unleashing the full potential of wireless communication systems. These antennas are versatile and can switch various performance modes in a simple yet ingenious structure. Based on the cutting-edge research, this paper deeply explores their core design principles, the latest breakthroughs, and the ingenious methods. Through an in-depth analysis of a multitude of reconfigurable antenna design cases, existing design methods are categorized into four categories: electronic and optical switches, structural physical change, smart materials, and bistable composites. Each category is subjected to a meticulous dissection, revealing the underlying design mechanisms, highlighting innovativeness, and discussing both the strengths and limitations. Furthermore, by conducting a comprehensive comparative analysis, this paper concludes the forthcoming challenges and prospective trajectories for this research domain. Therefore, this paper can serve as a valuable reference for researchers seeking to deepen their understanding and application of various reconfiguration methods in the design of reconfigurable antennas, guiding them toward the forefront of antenna technology innovation.

Xinyi Zheng, Chen Wei, Shenao Wang et al.

The exponential growth of open-source package ecosystems, particularly NPM and PyPI, has led to an alarming increase in software supply chain poisoning attacks. Existing static analysis methods struggle with high false positive rates and are easily thwarted by obfuscation and dynamic code execution techniques. While dynamic analysis approaches offer improvements, they often suffer from capturing non-package behaviors and employing simplistic testing strategies that fail to trigger sophisticated malicious behaviors. To address these challenges, we present OSCAR, a robust dynamic code poisoning detection pipeline for NPM and PyPI ecosystems. OSCAR fully executes packages in a sandbox environment, employs fuzz testing on exported functions and classes, and implements aspect-based behavior monitoring with tailored API hook points. We evaluate OSCAR against six existing tools using a comprehensive benchmark dataset of real-world malicious and benign packages. OSCAR achieves an F1 score of 0.95 in NPM and 0.91 in PyPI, confirming that OSCAR is as effective as the current state-of-the-art technologies. Furthermore, for benign packages exhibiting characteristics typical of malicious packages, OSCAR reduces the false positive rate by an average of 32.06% in NPM (from 34.63% to 2.57%) and 39.87% in PyPI (from 41.10% to 1.23%), compared to other tools, significantly reducing the workload of manual reviews in real-world deployments. In cooperation with Ant Group, a leading financial technology company, we have deployed OSCAR on its NPM and PyPI mirrors since January 2023, identifying 10,404 malicious NPM packages and 1,235 malicious PyPI packages over 18 months. This work not only bridges the gap between academic research and industrial application in code poisoning detection but also provides a robust and practical solution that has been thoroughly tested in a real-world industrial setting.

Dennis Junger, Max Westing, Christopher P. Freitag et al.

Progressing digitalization and increasing demand and use of software cause rises in energy- and resource consumption from information and communication technologies (ICT). This raises the issue of sustainability in ICT, which increasingly includes the sustainability of the software products themselves and the art of creating sustainable software. To this end, we conducted an analysis to gather and present existing literature on three research questions relating to the production of ecologically sustainable software ("Green Coding") and to provide orientation for stakeholders approaching the subject. We compile the approaches to Green Coding and Green Software Engineering (GSE) that have been published since 2010. Furthermore, we considered ways to integrate the findings into existing industrial processes and higher education curricula to influence future development in an environmentally friendly way.

K. Slimani, S. Khoulji, Aslane Mortreau et al.

Businesses in the telecommunications industry provide global communication using a variety of channels, including but not limited to mobile phones, landlines, satellites, the Internet, and other electronic media. These businesses built the networks that enable the global transfer of text, audio, speech, and video. Companies in the telecommunications industry include those that provide landline and cellular telephone service, as well as those that provide cable television, satellite television, and online access. Once upon a time, the telecommunications industry was dominated by a small group of extremely large multinational and regional conglomerates. The industry has been caught up in a wave of liberalization and innovation since the early 2000s. Government monopolies have been privatized in several nations, exposing them to an explosion of new rivals. As mobile services continue to grow at a faster rate than fixed-line ones, and as Internet traffic begins to surpass voice traffic as the dominant form of commerce, established marketplaces have been turned on their heads. The undertaken paper endeavors to highlight the vulnerabilities that the telecommunication networking sector could be facing in the present as well as the future in light of the usage of artificial intelligence as assistive and advanced tech.

Chinazaekpere Nwani, F. Bekun, P. Agboola et al.

Gangadharan Murugusundaramoorthy, kaliappan Vijaya, Hijaz Ahmad

The purpose of this paper is to consider coefficient estimates in a class of functions $\mathfrak{G}_{\vartheta}^κ(\mathcal{X},\varkappa)$ consisting of analytic functions $f$ normalized by $f(0)=f'(0)-1=0$\ in the open unit disk $Δ=\{ z:z\in \mathbb{C}\quad \text{and}\quad \left\vert z\right\vert <1\}$ subordinating generalized telephone numbers, to derive certain coefficient estimates $a_2,a_3$ and Fekete-Szegö inequality for $f\in\mathfrak{G}_{\vartheta}^κ(\mathcal{X},\varkappa)$. A similar results have been done for the function $ f^{-1} $ and $\log\dfrac{f(z)}{z}.$Similarly application of our results to certain functions defined by using convolution products with a normalized analytic function is given, and in particular we state Fekete-Szeg"{o} inequalities for subclasses described through Poisson Borel and Pascal distribution series.

Ankita Singh, Sudhakar Singh, Shiv Prakash

Wireless Mesh Network (WMN) is surely one of the prominent networks in the modern era which is widely used in numerous evolving applications, viz. broadband home networking (BHN), community and neighbourhood networks (CNN), coordinated network management (CNM), and intelligent transportation systems (ITS), etc. It is a wireless network (WN) with multi-hop formed by many fixed wireless mesh routers (WMR) that are connected wirelessly with a mesh-alike backbone arrangement. In the IEEE 802.11s network, the node selection, scalability, stability, density of the nodes, mobility of the nodes, transmission power, and routing are major issues that WMN suffers. In this paper, a critical review of MAC protocols and their Quality of Service (QoS) parameters for WMN is presented to attain a better understanding of MAC protocols. Furthermore, the critical comparative analysis and recommendation of MAC procedures for WMN using Multi-objective optimization and statistical testing framework are performed. This framework is used for the analysis and recommendation of different protocols available for QoS parameters.

N. Race, I. Eckley, A. Parlikad et al.

Qing-He Zhang, En-Yu Zhang, Shi-Hui Zhang

This article proposes a novel approach for the estimation of the direction-of-arrival (DoA) of multiple signals impinging on time-modulated arrays (TMAs). The algorithm transforms DoA estimation into compressive sensing (BCS) formulation to tackle the sparse signal problem. Based on the voltage outputs of the TMAs at multiple times instants, a strategy using multitasks BCS (MT-BCS) is applied to recover the DoA and improve the accuracy. The comparison with the existing algorithms of DoA estimation in TMAs verifies the effectiveness and feasibility of the proposed method.

Xue-Yong Fu, Cheng Chen, Md Tahmid Rahman Laskar et al.

We present a simple yet effective method to train a named entity recognition (NER) model that operates on business telephone conversation transcripts that contain noise due to the nature of spoken conversation and artifacts of automatic speech recognition. We first fine-tune LUKE, a state-of-the-art Named Entity Recognition (NER) model, on a limited amount of transcripts, then use it as the teacher model to teach a smaller DistilBERT-based student model using a large amount of weakly labeled data and a small amount of human-annotated data. The model achieves high accuracy while also satisfying the practical constraints for inclusion in a commercial telephony product: realtime performance when deployed on cost-effective CPUs rather than GPUs.

Mohammad Monirujjaman Khan, Kaisarul Islam, Md. Nakib Alam Shovon et al.

A 60 GHz compact and novel shaped microstrip-fed antenna based on a textile substrate for body-centric communications has been proposed in this paper. The antenna has a partial ground, and the textile substrate is made up of 1.5 mm thick 100% polyester. Two rectangular sections from the patch antenna’s radiator were removed to give the antenna a swan-shaped appearance. The antenna was designed and simulated using computer simulation technology (CST) microwave studio software. Simulated results show that, in free-space, the antenna achieved a high bandwidth of 11.6 GHz with a center frequency of 60.01 GHz. With 89.4% radiation efficiency, the maximum gain of the antenna was 8.535 dBi. For the on-body scenario, the antenna was simulated over five different distances from a human torso phantom. At the closest distance from the phantom, the antenna’s gain was 5.27 dBi, while the radiation dropped significantly to 63%. The highest bandwidth of 12.27 GHz was attained at 8 mm, while the lowest bandwidth of 5.012 GHz was attained at 4 mm away from the phantom. Gain and radiation efficiency were comparable to free-space results at the furthest distance. The antenna was also simulated with ten different textile substrates for both free-space and on-body scenarios. Among these ten substrates, denim, tween, and Quartzel fabric had similar performance results as polyester. This design achieved similar performance compared to other 60 GHz textile antennas while being a bit more compact. This antenna will be a promising choice for body-centric communications because of its compact size, textile-based substrate, and excellent on-body performance.

Ming-An Chung, Chih-Wei Yang

A miniaturized internal antenna with monopole structure is constituted, including three radiating strips of a compact prototype and a back-coupling pad to improve the impedance matching, which achieves a wide bandwidth of 2.972 GHz between the operating frequencies of 2315–5285 MHz, and is introduced and researched. There is an urgent need for a complete frequency-continuous and large bandwidth design in the current wireless communication design to achieve a multimode, multifrequency, physical phenomenon design with large bandwidth and continuous operating frequency. The recommended antenna provides a broadband operation in an electric vehicles (EVs) and Internet of Things (IoT) devices application embedded in the wireless communication standard for 5G, LTE, V2X, WLAN, WiMAX, Sirius/XM Radio, V2X, and DSRC to support the multiband application. This design is embedded side edge of overall placement in the device and is integrated applicable to the trend of heterogeneous wireless multiple access networks in electric vehicle and Internet of Things system devices, which covered the 5G with supporting the band of n7/n38/n40/n53/n77/n78/n79/n90, the 4G with supporting the band of 7/38/40/41/42/43/48/67, the V2X and DSRC for the operating frequencies between 2500 and 5000 MHz, the Sirius/XM Radio for the operating frequencies of 2320–2345 MHz, the ISM band of WiFi and BT covering the band of 2450–2483.5 and 5150–5350 MHz, and the WiMAX also supporting the band of 2300–2690 and 3400–3690 MHz. Moreover, the compact antenna manufactured an FR4 material with the antenna area of 5 × 10 × 0.8 mm3 and the ground area of 33.5 × 10 × 0.8 mm3. The proposed design better benefits a narrow space on the PCB with a low profile and is easy to make with a circuit board design.

Saad Hassan Kiani, Xin Cheng Ren, Adil Bashir et al.

In this research, a novel T shape antenna is proposed for millimetre-wave (mmwave) 5G systems. Designed on 0.254 mm thin Roggers 5880 substrate with a dielectric constant of 2.3 and the loss tangent of 0.0009, the proposed antenna offers a wideband characteristics of nearly 8 GHz with gain of 4.25 dBi for single element. Based on these characteristics, the single element is further constructed into a four-element linear array with a compact size of 18.5 × 24 mm2 The proposed antenna array exhibited dual beam radiation patterns with a high realized gain of 11.5 dBi and 94% efficiency. The measured results from the fabricated prototype well agree with the simulated results and thus, therefore, make the proposed antenna system a well-suited candidate for future mmwave devices.

Rohan Kumar Das, Ruijie Tao, Haizhou Li

This work provides a brief description of Human Language Technology (HLT) Laboratory, National University of Singapore (NUS) system submission for 2020 NIST conversational telephone speech (CTS) speaker recognition evaluation (SRE). The challenge focuses on evaluation under CTS data containing multilingual speech. The systems developed at HLT-NUS consider time-delay neural network (TDNN) x-vector and ECAPA-TDNN systems. We also perform domain adaption of probabilistic linear discriminant analysis (PLDA) model and adaptive s-norm on our systems. The score level fusion of TDNN x-vector and ECAPA-TDNN systems is carried out, which improves the final system performance of our submission to 2020 NIST CTS SRE.

Pavel Seda, M. Seda, Jiri Hosek

The need to optimize the deployment and maintenance costs for service delivery in wireless networks is an essential task for each service provider. The goal of this paper was to optimize the number of service centres (gNodeB) to cover selected customer locations based on the given requirements. This optimization need is especially emerging in emerging 5G and beyond cellular systems that are characterized by a large number of simultaneously connected devices, which is typically difficult to handle by the existing wireless systems. Currently, the network infrastructure planning tools used in the industry include Atoll Radio Planning Tool, RadioPlanner and others. These tools do not provide an automatic selection of a deployment position for specific gNodeB nodes in a given area with defined requirements. To design a network with those tools, a great deal of manual tasks that could be reduced by more sophisticated solutions are required. For that reason, our goal here and our main contribution of this paper were the development of new mathematical models that fit the currently emerging scenarios of wireless network deployment and maintenance. Next, we also provide the design and implementation of a verification methodology for these models through provided simulations. For the performance evaluation of the models, we utilize test datasets and discuss a case study scenario from a selected district in Central Europe.

Leonid B. Sokolinsky, Irina M. Sokolinskaya

In the development of industrial digital twins, the optimization problem of technological and business processes often arises. In many cases, this problem can be reduced to a large-scale linear programming (LP) problem. The article is devoted to the new method for solving large-scale LP problems. This method is called the "apex-method". The apex-method uses the predictor-corrector framework. The predictor step calculates a point belonging to the feasible region of LP problem. The corrector step calculates a sequence of points converging to the exact solution of the LP problem. The article gives a formal description of the apex-method and provides information about its parallel implementation in C++ language by using the MPI library. The results of large-scale computational experiments on a cluster computing system to study the scalability of the apex method are presented.