Hasil untuk "Telecommunication"

Anis Elgabli, Wessam Mesbah

In this paper, we start with a comprehensive evaluation of the effect of adding differential privacy (DP) to federated learning (FL) approaches, focusing on methodologies employing global (stochastic) gradient descent (SGD/GD), and local SGD/GD techniques. These global and local techniques are commonly referred to as FedSGD/FedGD and FedAvg, respectively. Our analysis reveals that, as far as only one local iteration is performed by each client before transmitting to the parameter server (PS) for FedGD, both FedGD and FedAvg achieve the same accuracy/loss for the same privacy guarantees, despite requiring different perturbation noise power. Furthermore, we propose a novel DP mechanism, which is shown to ensure privacy without compromising performance. In particular, we propose the sharing of a random seed (or a specified sequence of random seeds) among collaborative clients, where each client uses this seed to introduces perturbations to its updates prior to transmission to the PS. Importantly, due to the random seed sharing, clients possess the capability to negate the noise effects and recover their original global model. This mechanism preserves privacy both at a “curious” PS or at external eavesdroppers without compromising the performance of the final model at each client, thus mitigating the risk of inversion attacks aimed at retrieving (partially or fully) the clients’ data. Furthermore, the importance and effect of clipping in the practical implementation of DP mechanisms, in order to upper bound the perturbation noise, is discussed. Moreover, owing to the ability to cancel noise at individual clients, our proposed approach enables the introduction of arbitrarily high perturbation levels, and hence, clipping can be totally avoided, resulting in the same performance of noise-free standard FL approaches.

Hamed Hellaoui, Matti Laitila, Markus Isomäki et al.

The upcoming generation of mobile telecommunication systems is expected to support new use cases, where the mobile network serves one or more IP subnetworks located behind the User Equipment (UEs). This would create new challenges for the mobile system to efficiently serve such behind-UE subnetworks, as the latter are commonly not visible to the mobile system. In 3GPP, there have been works on Time-Sensitive Networking (TSN) and Deterministic Networking (DetNet), where the 5G System (5GS) is considered as a bridge or a DetNet node. In order to efficiently serve behind-UE IP subnetworks, we foresee the need for a further generalization where the mobile system (5GS and beyond) acts as a set of IP routers with more generic capabilities. In this article, we introduce the concept of Mobile System Router (MS-Router) which aims to provide a reference architectural design to enable the support of IP routing in the next generation of mobile telecommunication systems. The concept models a mobile system as an IP router per User Plane granularity. Each MS-Router implements an IP routing protocol, exchanges routing messages with the external routers and constructs a routing table, enabling the mobile system to dynamically learn the topology of the IP subnetwork behind the UEs and Data Network. The learned topology is translated into User Plane configuration to serve the IP subnetworks in an optimal way. The article also advocates different approaches where routing protocols can be implemented in the mobile system.

Karina Niyazova, Assel Mukasheva, Gani Balbayev et al.

The fight against financial crimes has become increasingly challenging, and the need for sophisticated systems that can accurately identify suspicious transactions has become more pressing. The goal of the study is to develop a new feature selection method based on swarm intelligence algorithms to improve the quality of data classification. This article is about the development of an information system for the classification of transactions into legal and suspicious in an anti-money laundering sphere. The system utilizes a swarm-algorithm-based feature selection approach, specifically the ant colony optimization algorithm, which was both used and adapted for this purpose The article also presents the system’s functional–structural diagram and feature selection algorithm flowchart. The proposed feature selection method can be used to classify data from various subject areas.

Khaled Alhassoon, Yaaqoub Malallah, Fahad N. Alsunaydih et al.

The design of the aperture-fed annular ring (AFAR) microstrip antenna is presented. This proposed design will ease the fabrication and usability of the 3D-printed and solderless 2D materials. This antenna consists of three layers: the patch, the slot within the ground plane as the power transfer medium, and the microstrip line as the feeding. The parameters of the proposed design are investigated using the finite element method FEM to achieve the 50 Ω impedance with the maximum front-to-back ratio of the radiation pattern. This study was performed based on four steps, each investigating one parameter at a time. These parameters were evaluated based on an initial design and prototype. The optimized design of 3D AFAR attained S₁₁ around 17 dB with a front-to-back ratio of more than 30 dB and a gain of around 3.3 dBi. This design eases the process of using a manufacturing process that involves 3D-printed and 2D metallic materials for antenna applications.

Seokwon Jang, Namseok Ko, Jaewook Lee et al.

To guarantee a high data transmission rate in heterogeneous mobile networks, sufficient small base stations (SBSs) and user plane function (UPF) instances should be active. However, the excessive operation of SBSs and UPF instances can increase the operating expenditure (OPEX) for the network operator. To balance the data rate and OPEX, we propose a joint UPF instance–SBS sched-uling algorithm (J-UBSA). In the proposed J-UBSA, a controller periodically determines the appropriate number of active SBSs and UPF instances based on estimated variations in session requests. The decision-making process is for-mulated as a constrained Markov decision process and converted into a linear programming model to obtain the optimal solution using a traditional algo-rithm with low complexity. Evaluation results demonstrate that J-UBSA can substantially reduce the OPEX while guaranteeing a suitable average data rate for mobile devices.

Shweta Singh, Manish Kumar, Rahul Kumar

Abstract Emerging wireless communication networks, exemplified by the evolution from 5G to subsequent technologies, necessitate extensive connectivity among myriad devices to fuel the ongoing technological progress. However, the magnitude of this network demands an extensive power source, requiring an advanced and sustainable system to be practically deployable. This study introduces a cutting‐edge system utilising ambient RF signals for both wireless information transfer (WIT) and wireless power transfer. The proposed system addresses the energy deficiencies of billions of low‐powered wireless devices within the network. Wireless‐powered communication networks (WPCN) and simultaneous wireless energy and power transfer (SWIPT) technologies, operating on ambient RF signals, provide a solution for the energy requirements of these devices. Harvesting energy from ambient RF signals is pivotal for the signal transmissions of WPCN and SWIPT systems. The research focuses on enhancing the efficiency and feasibility of such systems, emphasising aspects like maximising energy efficiency (EE) and improving outage performance (OP). The paper underscores the ubiquitous connectivity resulting from node mobility and delves into the emerging models of WPCN and SWIPT, along with collaborative technologies integrated with these models. It explores resource allocation (RA), multiple‐input multiple‐output (MIMO) technology in the context of WPCN, and various aspects of relaying operations, including SWIPT‐MIMO and SWIPT receiver architecture. Conclusively, the comprehensive survey affirms that leveraging ambient RF signals for WIT and power transfer can significantly enhance EE, OP, RA, and overall network capabilities. This improvement positions the proposed system as a promising solution for meeting the connectivity demands of future wireless communication technologies.

Parsa H. S. Panahi, Amir H. Jalilvand, Abolfazl Diyanat

The Internet service provider industry is currently experiencing intense competition as companies strive to provide top-notch services to their customers. Providers are introducing cutting-edge technologies to enhance service quality, understanding that their survival depends on the level of service they offer. However, evaluating service quality is a complex task. A crucial aspect of this evaluation lies in understanding user experience, which significantly impacts the success and reputation of a service or product. Ensuring a seamless and positive user experience is essential for attracting and retaining customers. To date, much effort has been devoted to developing tools for measuring Quality of Experience (QoE), which incorporate both subjective and objective criteria. These tools, available in closed and open-source formats, are accessible to organizations and contribute to improving user experience quality. This review article delves into recent research and initiatives aimed at creating frameworks for assessing user QoE. It also explores the integration of machine learning algorithms to enhance these tools for future advancements. Additionally, the article examines current challenges and envisions future directions in the development of these measurement tools.

Adebola Olutayo, Yanjie Dong, Julian Cheng et al.

Performance of wireless powered wireless systems is analyzed. The wireless devices in such systems scavenge energy from sources in downlinks and use the energy to communicate in uplinks. We introduce two new models for these energy harvesters to consider their nonlinear circuitry and their functioning over multiple line-of-sight and non-line-of-sight channels. The newly proposed Beaulieu-Xie fading model is used to characterize this manifold of channels. Performance analyses of average harvested energy and transmission outage probability show good fit between the proposed models and measured data.

Yun LI, Qian GAO, Zhixiu YAO et al.

To solve the problems of low efficiency of network service caching and computing-networking resource allocation caused by tasks differentiation, highly dynamic network environment, and decentralized computing-networking resource deployment in edge networks, a decentralized service arrangement and computing offloading model for mobile edge computing was investigated and established.Considering the multidimensional resource constraints, e.g., computing power, storage, and bandwidth, with the objective of minimizing task processing latency, the joint optimization of service caching and computing-networking resource allocation was abstracted as a partially observable Markov decision process.Considering the temporal dependency of service request and its coupling relationship with service caching, a long short-term memory network was introduced to capture time-related network state information.Then, based on recurrent multi-agent deep reinforcement learning, a distributed service arrangement and resource allocation algorithm was proposed to autonomously decide service caching and computing-networking resource allocation strategies.Simulation results demonstrate that significant performance improvements in terms of cache hit rate and task processing latency achieved by the proposed algorithm.

Eric Tutu Tchao, Simon Atuah Asakipaam, Yesuenyeagbe Atsu Kwabla Fiagbe et al.

A recent assessment of a pilot concentrating solar power plant in Ghana noticed the failure of the tracking system to accurately align the multifaceted heliostats toward the sun and focus the sunbeams onto the target. A further review of solar tracking systems revealed the limitation of concentrated solar power tracking systems to simultaneously improve accuracy and reduce operational cost. In this paper, a computer vision-based solar tracking system, comprising a vision controller, webcam, light sensor, Arduino microcontroller, two stepper motors, a stick, and a transparent plate, is proposed and implemented. The light sensor indicates the presence or absence of sunlight, the webcam captures the image of the stick's shadow on the plate and the vision controller reads this data from the webcam and processes it to extract the solar angles. The angles are sent to the microcontroller which uses them to orient the heliostat appropriately through the stepper motors. The proposed system is location independent and can be installed in each heliostat or a group of heliostats. the preliminary tests show it tracks the sun accurately and exhibits minimal operation cost.

Giovanni Grieco, Giovanni Iacovelli, Pietro Boccadoro et al.

The Internet of Drones (IoD) is a networking architecture that stems from the interplay between Unmanned Aerial Vehicles (UAVs) and wireless communication technologies. Networked drones can unleash disruptive scenarios in many application domains. At the same time, to really capitalize their potential, accurate modeling techniques are required to catch the fine details that characterize the features and limitations of UAVs, wireless communications, and networking protocols. To this end, the present contribution proposes the Internet of Drones Simulator (IoD-Sim), a comprehensive and versatile open source tool that addresses the many facets of the IoD. IoD-Sim is a Network Simulator 3 (ns-3)-based simulator organized in a 3-layer stack, composed by (i) the Underlying Platform, which provides the telecommunication primitives for different standardized protocol stacks, (ii) the Core, that implements all the fundamental features of an IoD scenario, and (iii) the Simulation Development Platform, mainly composed by a set of tools that speeds up the graphical design for every possible use-case. In order to prove the huge potential of this proposal, three different scenarios are presented and analyzed from both a software perspective and a telecommunication standpoint. The peculiarities of this open-source tool are of interest for researchers in academia, as they will be able to extend to model upcoming specifications, including, but not limited to, mobile networks and satellite communications. Still, it will certainly be of relevance in industry to accelerate the design phase, thus improving the time-to-market of IoD-based services.

Hyun Joo Park, Kang-Hyeon Choi, Jong-Won Yu

In this paper, we propose the implementation of a safety device that generates an alarm sound or braking operation to reduce the risk of accidents. It reduces the exposure of risks due to non-wearing by supplementing the function of the helmet for safety. For machine learning, the safety state is learned by using two types of sensing data, and when an abnormal helmet use or speed or drinking driving is detected, an alarm sound is generated and motion is broken to maintain the safe state. By measuring data using a gas sensor, alcohol is checked and this is used as abnormal data. Users form a habit of wearing safety equipment with continuous safety alarm sound and speed braking and proper driving habit by driving in a normal state without drinking alcohol. In addition, the proposed system enables real-time monitoring, thereby reducing risks by continuously maintaining safe driving and wearing protective equipment. The proposed system uses artificial intelligence to discriminate data related to helmet wearing, speed, and drinking in making an electric kickboard for safety, and triggers an alarm or operates the brake to prevent abnormal driving. If the design and function are supplemented, it will become a basic function that can be applied to various equipment of transportation.

Vít Novotný, Petr Sysel, Aleš Prokeš et al.

The distributed long-range sensing system, using the standard telecommunication single-mode optical fiber for the distributed sensing of mechanical vibrations, is described. Various events generating vibrations, such as a walking or running person, moving car, train, and many other vibration sources, can be detected, localized, and classified. The sensor is based on phase-sensitive optical time-domain reflectometry (ϕ-OTDR). Related sensing system components were designed and constructed, and the system was tested both in the laboratory and in the real deployment, with an 88 km telecom optical link, and the results are presented in this paper. A two-fiber sensor unit, with a double-sensing range was also designed, and its scheme is described. The unit was constructed and the initial measurement results are presented.

Sajjad Taravati, George V. Eleftheriades

Metasurfaces are ultrathin structures which are constituted by an array of subwavelength scatterers with designable scattering responses. They have opened up unprecedented exciting opportunities for extraordinary wave engineering processes. On the other hand, frequency converters have drawn wide attention due to their vital applications in telecommunication systems, health care devices, radio astronomy, military radars and biological sensing systems. Here, we show that a spurious-free and linear frequency converter metasurface can be realized by leveraging unique properties of engineered transmissive temporal supercells. Such a metasurface is formed by time-modulated supercells; themselves are composed of temporal and static patch resonators and phase shifters. This represents the first frequency converter metasurface possessing large frequency conversion ratio with controllable frequency bands and transmission magnitude. In contrast to conventional nonlinear mixers, the proposed temporal frequency converter offers a linear response. In addition, by taking advantage of the proposed surface-interconnector-phaser-surface (SIPS) architecture, a spurious-free and linear frequency conversion is achievable, where all undesired mixing products are strongly suppressed. The proposed metasurface may be digitally controlled and programmed through a field programmable gate array. This makes the spurious-free and linear frequency converter metasurface a prominent solution for wireless and satellite telecommunication systems, as well as invisibility cloaks and radars. This study opens a way to realize more complicated and enhanced-efficiency spectrum-changing metasurface.

Zhuoran Fang, Jiajiu Zheng, Abhi Saxena et al.

Phase change materials (PCMs) have long been used as a storage medium in rewritable compact disk and later in random access memory. In recent years, the integration of PCMs with nanophotonic structures has introduced a new paradigm for non-volatile reconfigurable optics. However, the high loss of the archetypal PCM Ge2Sb2Te5 in both visible and telecommunication wavelengths has fundamentally limited its applications. Sb2S3 has recently emerged as a wide-bandgap PCM with transparency windows ranging from 610nm to near-IR. In this paper, the strong optical phase modulation and low optical loss of Sb2S3 are experimentally demonstrated for the first time in integrated photonic platforms at both 750nm and 1550nm. As opposed to silicon, the thermo-optic coefficient of Sb2S3 is shown to be negative, making the Sb2S3-Si hybrid platform less sensitive to thermal fluctuation. Finally, a Sb2S3 integrated non-volatile microring switch is demonstrated which can be tuned electrically between a high and low transmission state with a contrast over 30dB. Our work experimentally verified the prominent phase modification and low loss of Sb2S3 in wavelength ranges relevant for both solid-state quantum emitter and telecommunication, enabling potential applications such as optical field programmable gate array, post-fabrication trimming, and large-scale integrated quantum photonic network.

Aaron Zimba, Tozgani Fainess Mbale, Mumbi Chishimba et al.

Telecommunication reforms in Zambia and the subsequent liberalisation of the international gateway was perceived as one of the means of promoting social and economic growth in both the urban and rural areas of the country. The outcome of this undertaking propelled the rapid development of Internet which has evidently brought about unprecedented paradigm shifts in the use of Information and Communication Technologies (ICTs). It is indisputable that ICTs, and the Internet in particular, have revolutionalised the way we communicate today. Furthermore, the penetration of ICTs to other spheres of our daily lives is evidence enough that the impacts thereof go beyond mere communicative facets of our lives. However, many challenges arose in the implementation of telecommunications reforms. In order to achieve the status quo, government had to make strategic liberalisation policies in the telecoms sector that saw the opening up of the international communication gateways to the private sector. This is in tandem with the fact that the relationship between government (through its formulation of policies and regulations) and other stakeholders determines the ability of a country to generate and use advanced knowledge for industrial competitiveness. As such, in this paper, we present the genesis and evaluate the impacts associated with the telecommunications reforms and the subsequent liberalisation of international communication gateways, and Internet development in Zambia. We further consider the challenges this has brought about and discuss possible future directions. This is helpful in forecasting the future landscape of the ICT sector considering that the country seeks to achieve universal coverage of both Internet and communication facilities to all Zambians across the country.

Maryam Daryalal, Hamed Pouya

Telecommunication networks frequently face technological advancements and need to upgrade their infrastructure. Adapting legacy networks to the latest technology requires synchronized technicians responsible for migrating the equipment. The goal of the network migration problem is to find an optimal plan for this process. This is a defining step in the customer acquisition of telecommunications service suppliers, and its outcome directly impacts the network owners' purchasing behaviour. We propose the first exact method for the network migration problem, a logic-based Benders decomposition approach that benefits from a hybrid constraint programming-based column generation in its master problem and a constraint programming model in its subproblem. This integrated solution technique is applicable to any integer programming problem with similar structure, most notably the vehicle routing problem with node synchronization constraints. Comprehensive evaluation of our method over instances based on six real networks demonstrates the computational efficiency of the algorithm in obtaining quality solutions. We also show the merit of each incorporated optimization paradigm in achieving this performance.

Charles Ciret, Koen Alexander, Nicolas Poulvellarie et al.

We model second harmonic generation in subwavelength III-V-on-insulator waveguides. The large index contrast induces strong longitudinal electric field components that play an important role in the nonlinear conversion. We show that many different waveguide dimensions are suitable for efficient conversion of a fundamental quasi-TE pump mode around the 1550 nm telecommunication wavelength to a higher-order second harmonic mode.

Nameer Hashim Qasim, Volodymyr Pyliavskyi, Valentina Solodka

The analysis of metrological agents for the estimation of the quality of telecommunication path treatments is carried out. Analysis of subjective and objective estimation methods is presented. The justification for choosing an objective method of measuring is presented. Are reported a list of existing goals and objectives, which face the current progress of the implementation of promising systems for broadcasting and improvement of existing ones. The latter include the absence of normative documents and recommendations for optical specimens of testing tables, etc. Researches related to the choice of optical samples from existing sets of colors from a number of international documents and recommendations are presented. Deficiency of these sets is substantiated, as some of the colors necessary for evaluation of telecommunication paths cannot be provided with no color of sets. Provides recommendations and refinements about which colors from existing sets should be used and what constraints exist when used and how to solve. It is shown, that saturated colors of green and red colors are not provided with spectral from the existing sets, therefore, it is proposed to expand the traditional understanding of metrological means by using atlases of colors. Satin colors In contrast to existing ones have a number of advantages and can be used for evaluation in advanced conditions, rather than in the studio that is rigidly defined by the regulations. It is noted that for different brightness values there are a different number of testing points. The number of testing points directly depends on the evaluation criteria, is driven by several possible sets of colors for evaluation. Recommendations for other evaluation conditions are provided. Use satin colors to construct testing tables

Christophe Finot, Hervé Rigneault

Using the space-time duality we theoretically and experimentally revisit the Arago spot formation in the time domain and explore the temporal emergence of a bright spot in the time shadow of an initial waveform. We describe the linear regime of propagation using Fresnel's integrals and show that in the presence of Kerr nonlinearity the Arago spot formation is affected depending on the sign of the dispersion. We finally confirm experimentally the Arago spot formation in the time domain using a telecommunication optical fiber platform.