Data Link Research Articles

Improved performance of hybrid optical communications system

Frees Space Optical (FSO) system employs empty space to transfer information between the transmitter and receiver using light. The single-beam Single Input Single Output (SISO) technology is well known for being subject to air attenuation induced by weather conditions, which decreases the performance link range and data quality. The proposed system in this research is a combination of DWDM and MIMO approaches to address this issue. The research is based on Optisystem simulations with various weather reduction in many of FSO systems: the FSO-DWDM-SISO (FDS) scheme and the suggested FSO-Hybrid-DWDM-MIMO method (FHDM). FHDM technology has considerably enhanced connection distance, received power, scalability, and data speed. At a data rate of 500 Mb/s, an evaluation is made between the suggested method and the FDS with respect to quality-factor during varied weather reduction using different numbers of optical transmission beams. The results show that the FHDM system improves connection distance, received optical power, minimum bit error rate (BER), and highest quality-factor significantly during various weather conditions.

A Packet Delay Assessment Model in the Data Link Layer of the LTE

The issues of modeling and evaluating the characteristics of the LTE data link layer functioning are considered. Transmitting packets in the data link layer are represented by a probabilistic-temporal graph consisting of two subgraphs. The first subgraph describes the operation of the HARQ protocol, and the second subgraph describes the operation of the ARQ protocol. The first subgraph is nested within the second subgraph. The probabilities of correct reception, non-error detection, and retransmission of packets in the MAC and RLC layers and generating functions of the packet service time based on the HARQ and ARQ protocols are determined. With the help of generating functions, the average value, variance, and coefficient of variation of the packet service time are determined. To calculate the average packet delay time in the LTE data link layer, the type of queuing system is selected, taking into account the coefficient of variation of the packet service time. The analysis of packets' delay time in the network's data link layer is carried out for different values of the intensity of packet arrival and the probabilities of a bit error in the physical layer of the network. For the sustainable functioning of the data link layer of the network, the limit values of the intensity of the arrival of packets are determined for a given probability of a bit error in the physical layer of the network.

ПРОТОКОЛЫ ПОЛНОСТЬЮ ОПТИЧЕСКИХ БОРТОВЫХ СЕТЕЙ

The article presents the concept of all-optical on-board networks (AOON). AOON protocol stack is described, the operation of the transport layer, data link layer and the management layer of the AOON protocol stack is considered in details. The article also describes a software model designed to check the correctness of operation of the AOON protocol stack from a functional point of view, and an example of the developed software model is provided.

Impact of Eurasian autumn snow on the winter North Atlantic Oscillation in seasonal forecasts of the 20th century

Abstract. As the leading climate mode of wintertime climate variability over Europe, the North Atlantic Oscillation (NAO) has been extensively studied over the last decades. Recently, studies highlighted the state of the Eurasian cryosphere as a possible predictor for the wintertime NAO. However, missing correlation between snow cover and wintertime NAO in climate model experiments and strong non-stationarity of this link in reanalysis data are questioning the causality of this relationship. Here we use the large ensemble of Atmospheric Seasonal Forecasts of the 20th Century (ASF-20C) with the European Centre for Medium-Range Weather Forecasts model, focusing on the winter season. Besides the main 110-year ensemble of 51 members, we investigate a second, perturbed ensemble of 21 members where initial (November) land conditions over the Northern Hemisphere are swapped from neighboring years. The Eurasian snow–NAO linkage is examined in terms of a longitudinal snow depth dipole across Eurasia. Subsampling the perturbed forecast ensemble and contrasting members with high and low initial snow dipole conditions, we found that their composite difference indicates more negative NAO states in the following winter (DJF) after positive west-to-east snow depth gradients at the beginning of November. Surface and atmospheric forecast anomalies through the troposphere and stratosphere associated with the anomalous positive snow dipole consist of colder early winter surface temperatures over eastern Eurasia, an enhanced Ural ridge and increased vertical energy fluxes into the stratosphere, with a subsequent negative NAO-like signature in the troposphere. We thus confirm the existence of a causal connection between autumn snow patterns and subsequent winter circulation in the ASF-20C forecasting system.

Beacon-Based Hybrid Routing Protocol for Large-Scale Unmanned Vehicle Ad Hoc Network

In this paper, we designed a beacon-based hybrid routing protocol to adapt to the new forms of intelligent warfare, accelerate the application of unmanned vehicles in the military field, and solve the problems such as high maintenance cost, path failure, and repeated routing pathfinding in large-scale unmanned vehicle network communications for new battlefields. This protocol used the periodic broadcast pulses initiated by the beacon nodes to provide synchronization and routing to the network and established a spanning tree through which the nodes communicated with each other. An NS3 platform was used to build a dynamic simulation environment of service data to evaluate the network performance. The results showed that when it was used in a range of 5 ~ 35 communication links, the beacon-based routing protocol’s PDR was approximately 10% higher than that of AODV routing protocol. At 5 ~ 50 communication links, the result was approximately 20% higher than the DSDV routing protocol. The routing load was not related to the number of nodes and communication link data and the protocol had better performance than traditional AODV and DSDV routing protocol, which reduced the cost of the routing protocol and effectively improved the stability and reliability of the network. The protocol we designed is more suitable for the scenarios of large-scale unmanned vehicle network communication in the future AI battlefield.

A Decoupled Access Scheme With Reinforcement Learning Power Control for Cellular-Enabled UAVs

This article proposes a downlink/uplink decoupled (DUDe) access scheme for cellular-enabled unmanned aerial vehicle (UAV) communication systems. To minimize interference, the proposed scheme separates the control and data links of UAVs, as well as the uplinks (ULs) and downlinks (DLs) of ground users (GUEs), onto different serving base stations and operating frequencies. Since power availability is a major constraint in UAV communications, two power allocation schemes based on <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> -learning (QL) and deep <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> -learning (DQL) are proposed to optimize the communication energy efficiency (EE) of this DUDe network. To quantify the improvements achieved, the proposed schemes are compared with the fractional power control (FPC) scheme used in 4G and 5G networks, as well as a convex optimization-based optimal power allocation scheme. The results demonstrate that the proposed DUDe scheme can achieve up to several times higher sum rates and EE in the UL direction than its coupled counterparts. Moreover, it is shown that the EE performance of the QL and DQL power allocation schemes approach the optimal performance and surpass the conventional FPC scheme by 80%–100% in the UHF band, and by 160%–170% in the mmWave band.

An RX AFE With Programmable BP Filter and Digitization for Ultrasound Harmonic Imaging.

This paper presents a front-end integrated circuit for ultrasound (US) harmonic imaging, interfacing to a one-dimensional capacitive micromachined ultrasonic transducer (CMUT). It contains a complete ultrasound receiving chain, from analog front-end (AFE) to gigabit/s data link. A two-stage self-biased inverter-based transimpedance amplifier (TIA) is proposed in this work to improve tradeoffs between power, noise, and linearity at the first stage. To improve harmonic imaging performance, the design is further equipped with a 4[Formula: see text]-order highly programmable bandpass filter, which has a tunable bandwidth from 2 MHz to 15 MHz. An 8 b 80 MS/s SAR ADC digitizes the signal, which is further encoded and serialized into an LVDS data link, enabling a reduction in the number of output cables for future systems with multiple ADCs. The design is realized in a 40 nm CMOS technology. Electrical measurements show it consumes 2.9 mW for the AFE and 2.1 mW for the ADC and digital blocks. Its overall dynamic range varies from 61 dB to 69 dB, depending on the reception bandwidth. The imaging capability of this design is further demonstrated in a US transmission and reception imaging system. The acoustic measurements prove successful ultrasound harmonic acquisition, where the on-chip bandpass filter can improve the lateral resolution by more than 30%.

Enabling the Internet of Things With CubeSats: A review of representative beamsteerable antenna concepts

The advent of CubeSats has empowered the vision of using a satellite constellation to provide seamless Internet coverage across the globe. This vision, known as the Internet of Space (IoS), is the key enabler of the Internet of Things (IoT). One of the major challenges in making IoS a reality is the development of an antenna system that can sustain a high data-rate link while being amenable to integration with the small CubeSat form factor. This challenge is further magnified by the requirement that the antenna dynamically reconfigures its radiation pattern to illuminate geographical areas that demand more coverage. The aim of this article is to provide an overview of antenna concepts developed by representative researchers that can overcome these challenges. If properly tailored for specific CubeSat applications, these concepts can make CubeSat-based IoS a realizable vision. We also highlight the open challenges and technology gaps that future research must address to make IoT a reality.

A Design Method of File Exchange-Based Point-to-Point Ordered Reliable Data Link Service

A Design Method of File Exchange-Based Point-to-Point Ordered Reliable Data Link Service

Library and information science research in the Arab World: a bibliometric analysis 1951–2021

PurposeThis study aims to investigate the research productivity of library and information science (LIS) authors affiliated with the 22 countries of the Arab League. It also identifies the top countries, organizations, authors, journals, natures of collaboration, and frequently used keywords in LIS research in the Arab world.Design/methodology/approachBibliometric methods were used to evaluate the research performance of the authors affiliated with library organizations in the Arab region. The Elsevier Scopus database was selected for data retrieval. A comprehensive search strategy was adopted to retrieve 863 publications contributed by LIS authors affiliated with the Arab countries. VOS viewer, Biblioshiny, BiblioAnalyitics, Microsoft Access and Microsoft Excel were used for data visualization and analysis.FindingsThis paper presents the dynamics and the state of the LIS research in the Arab region published between 1951 and 2021. The results of the study have highlighted an upward trend in the growth of the publications, especially in the past four years. The largest number of studies were published in the year 2020. The country-wise analysis ranked Kuwait and Saudi Arabia as the top LIS research producing countries with five and four researchers, respectively. The Kuwait University, the King Fahd University of Petroleum and Minerals and the Imam Abdulrahman Bin Faisal University were the three most productive organizations. Academic libraries, social media, bibliometrics, information-seeking behavior, information literacy and knowledge management were identified as the major areas of interest for the researchers. Internet and open access were topics that had gained recent popularity, while the digital library, research data management, green librarianship, link data, cloud computing, library leadership, library automation and artificial intelligence were identified as areas requiring further attention. Furthermore, the single-author pattern was found to be the most preferred pattern.Practical implicationsThe findings of this study would help prospective researchers in choosing the neglected areas of research that require further investigation. They would also help policymakers in identifying factors that need more attention and allocation of research funds.Originality/valueTo the best of the authors’ knowledge, this is the first comprehensive bibliometric study that presents a holistic picture of the LIS research in the Arab region.

IMPSO and Linear Programming-Based Energy-Efficient Cell Association Algorithm for Backhaul-Constrained Ultra-Dense Small-Cell Networks

This paper studies the energy efficiency optimization problem for coordinated multipoint (CoMP)-enabled and backhaul-constrained ultra-dense small-cell networks (UDNs). Energy efficiency is an eternal topic for future wireless communication networks; however, taking actual bottleneck of the backhaul link and the coordinated network architecture into consideration, it is difficult to find an effective way to improve the energy efficiency of the network. Aiming at this problem, we propose to combine cell association, subchannel allocation, backhaul resource allocation, and sleep/on of the cells together to develop an optimization algorithm for energy efficiency in UDN and then solve the formulated energy efficiency optimization problem by means of improved modified particle swarm optimization (IMPSO) and linear programming in mathematics. Simulation results indicate that nearly 13 % energy cost saving and 21 % energy efficiency improvement can be obtained by combining IMPSO with linear programming, and the backhaul link data rate can be improved by 30 % as the number of small cells increases. From the results, it can be found that by combining IMPSO with linear programming, the proposed algorithm can improve the network energy efficiency effectively at the expense of limited complexity.

Ultra‐wideband antenna system for in‐band full‐duplex applications

In this study, we present an ultra-wideband full-duplex system constituted of a wideband 4-element Vivaldi array and wideband microstrip-to-slotline baluns. The proposed system is characterised by its simplicity, high directivity, and high self-interference cancellation levels over a wide frequency bandwidth. The system is fabricated using basic printed-circuit board (PCB) technology and can provide at least 50 dB of self-interference cancellation over the bandwidth of operation, 4–40 GHz, with an average gain of 7.8 dBi. The system has a size of 8 cm × 8 cm × 9.4 cm and can be used as a high data rate link between two distant wireless nodes. To assess the merits of the proposed system and compare it to other published works, a new figure of merit (FoMWFD) dedicated to wide-band full-duplex antenna topologies is introduced in this study.

5G Network Data Migration Service Based on Edge Computing

With the development of mobile network technology, the continuous increase of mobile traffic has put forward higher requirements for quality of service (QoS) issues such as asymmetric transmission delay. The paper mainly studies the energy distribution problem on the migration data link from the terminal device to the edge node in the mobile edge network. Multiple data service packages are set up at each hop on the migration data link, and these data service packages compete with each other, and ultimately only one terminal provides and stores energy for this hop. The migration strategy of the data service package is affected by the edge node, and the edge node changes the migration strategy according to the migration strategy of the data service package. The paper is based on the formation of nodes between the data service packages of different nodes on the 5G network data link to jointly control the migration strategy, coordinate the migration strategy formulated, and better coordinate the migration strategy. In this competitive game model, the optimal migration strategy of nodes is found out according to the terminal equipment access requirements. Then according to the node stability rules, the composition of nodes when the nodes are stable is obtained, the migration strategy of stable nodes and the migration and spectrum strategies of operators are obtained, and the migration strategy of joint control provides energy for edge nodes.

Surface Waves Analysis of Efficient Underwater Radio-Based Wireless Link

The domain of underwater wireless communication (UWC) link is gaining much attention due to an increase in various underwater activities such as offshore hydrocarbon exploration, underwater unmanned vehicles (UUV), and military practices. Increased bandwidth and a reliable data link are mainly required for such activities. Both requirements of the domain are heavily affected by the highly conductive property of the seawater. This paper demonstrates the performance evaluation of radiofrequency-UWC, focusing on surface wave analysis, to propose a reliable solution for offshore activities. A constructive interference scheme can be useful due to the sharp difference in the properties of the two mediums (air and seawater). To that end, an experimental setup is created, and a corresponding finite element method (FEM) based simulation of the radio-based wireless link is run. This is because it has higher bandwidth and speed than acoustic and optical approaches. A conduction current mechanism transmits and receives data in a synthetic water tank containing a prepared conductive media (saltwater). The study of changing depths of transmitter-receiver nodes in saltwater shows that surface waves cause significant noise reception in shallow water (less than dipole length, below water level). During a series of experiments in the tank, the lowest bit error rate (BER) is observed only when the node’s submerged height was greater than dipole length. As a result, it is meant to provide a genuine data channel model. The discovery and analysis will aid in the development of a dependable underwater data link, with applications including short-range diver-to-diver communication, and UUV capability.

A Method and Analysis to Enable Efficient Piezoelectric Transducer-Based Ultrasonic Power and Data Links for Miniaturized Implantable Medical Devices.

Acoustic links for implantable medical devices (implants) have gained attention primarily because they provide a route to wireless deep-tissue systems. The miniaturization of the implants is a key research goal in these efforts, nominally because smaller implants result in less acute tissue damage. Implant size in most acoustic systems is limited by the piezoelectric bulk crystal used for power harvesting and data communication. Further miniaturization of the piezocrystal can degrade system power transfer efficiency and data transfer reliability. Here, we present a new method for packaging the implant piezocrystal; the method maximizes power transfer efficiency ( η ) from the acoustic power at the piezo surface to the power delivered to the electrical load and information transfer across the acoustic link. Our method relies on placing piezo-to-substrate anchors to the piezo regions where the vibrational displacement of the mode of interest is zero. To evaluate our method, we investigated packaged 1×1×1 mm3 piezocrystals assembled with different sized anchors. Our results show that reducing the anchor size decreases anchor loss and thus improves piezo quality factor (Q). We also demonstrate that this method improves system electromechanical coupling. A strongly coupled, high-Q piezo with properly sized and located anchors is demonstrated to achieve significantly higher η and superior data transfer capability at resonance. Overall, this work provides an analysis and generic method for packaging the implant piezocrystal that enables the design of efficient acoustic power and data links, which provides a path toward the further miniaturization of ultrasonic implants to submillimeter scales.

Dual-Polarized Antenna With Dual-Differential Integrated Feeding for Wideband Full-Duplex Systems

A new two-port dual-polarized planar antenna with an integrated feeding circuit for in-band full-duplex (FD) (IBFD) applications is presented. The antenna consists of four H-shape slots, stacked patches for enhanced bandwidth (BW), and a separate layer of two differential (0° and 180° split) power dividers connected using vertical transmission lines which define the feeding system. The multilayer antenna is well matched from about 2.2 to 2.5 GHz with isolation values from about 40 to 60 dB. When compared to similar IBFD antenna systems, the proposed configuration provides a higher isolation BW (10%) and higher gain (7.8 dBi) whilst adopting a simple feeding network. Also, by using the proposed feeding circuit, the manufactured antenna does not require any external cables and couplers. This simplifies the structure and reduces the number of cable connections. This allows for other analog-based self-interference reduction schemes for further improvements in the transmit and receive data link. In addition, the proposed antenna design was extended to a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4 \times 1$ </tex-math></inline-formula> array. These dual-differential IBFD antenna systems are a good alternative to more conventional FD designs which typically require external coupler-based feeding. In addition, the operating BWs and isolation values offered by these S-band systems can support new data link possibilities for beam steering and future IBFD wireless networks by low-cost antenna and feeding circuit integration.

An ASK Data Demodulator Circuit for Implantable Medical Devices Supporting a Minimum Modulation Depth of 0.034.

Amplitude shift keying (ASK) data demodulation method has been widely used for simultaneous wireless data and power transfer in implantable medical devices (IMDs). Small amplitude modulation depth (MD) is usually preferred as it helps promote energy harvesting efficiency. This paper presents an ASK data demodulator that has good immunity to disturbances and can demodulate ultra-low MD ASK signal. A three-stage amplifying structure (3SAS) is proposed, in which the common-mode level of each amplifier is set between the high and low levels of its input signal envelope to prevent amplifier gain saturation and maximize the amplification of the envelope difference. Two envelope detectors (EDs) are used before and after the 3SAS respectively. The first one is to obtain a coarse envelope for 3SAS input and the second one is to further suppress the residual carrier interference and get a fine envelope. The proposed demodulator is implemented in 0.18-μm high-voltage Bipolar-CMOS-DMOS (BCD) technology. The detectable MD is measured as low as 0.034%, showing that the proposed demodulator can work smoothly and robustly in some extreme cases of simultaneous data and power transferring.Clinical Relevance- The ASK data demodulator proposed in this paper supports ultra-low modulation depth. This reduces the bit error rate of the data link and keeps a highly power conversion efficiency for wireless power and data transfer in implantable medical devices.

Review of the Literature on Smart Grid Cybersecurity

The existing power generation grid with in United States seems to be an antiquated architecture, and the Home Automation is an overhaul that will contain a new features to fit customers' evolving power demands. Updating a systematic approach like the electricity network has the ability to bring new security vulnerabilities. This article gives an outline of the efforts undertaken in the field of Renewable Energy cyber security. Controller (PCS) Risk, Proposed Smart Stability, Electric Grid Model Based Security, Distributed Generation Data Link Protection, and Smart Grid Simulations for Security Research are really the areas that make up various pieces of the Smart Grid. The Power System is a vast, intricate infrastructure that still needs substantial cyber defense preparation.

Privacy preserving defect prediction using generalization and entropy-based data reduction

The software engineering community produces data that can be analyzed to enhance the quality of future software products, and data regarding software defects can be used by data scientists to create defect predictors. However, sharing such data raises privacy concerns, since sensitive software features are usually considered as business assets that should be protected in accordance with the law. Early research efforts on protecting the privacy of software data found that applying conventional data anonymization to mask sensitive attributes of software features degrades the quality of the shared data. In addition, data produced by such approaches is not immune to attacks such as inference and background knowledge attacks. This research proposes a new approach to share protected release of software defects data that can still be used in data science algorithms. We created a generalization (clustering)-based approach to anonymize sensitive software attributes. Tomek link and AllNN data reduction approaches were used to discard noisy records that may affect the usefulness of the shared data. The proposed approach considers diversity of sensitive attributes as an important factor to avoid inference and background knowledge attacks on the anonymized data, therefore data discarded is removed from both defective and non-defective records. We conducted experiments conducted on several benchmark software defect datasets, using both data quality and privacy measures to evaluate the proposed approach. Our findings showed that the proposed approach outperforms existing well-known techniques using accuracy and privacy measures.

Toward coherent O-band data center interconnects

Upcoming generations of coherent intra/inter data center interconnects currently lack a clear path toward a reduction of cost and power consumption, which are the driving factors for these data links. In this work, the tradeoffs associated with a transition from coherent C-band to O-band silicon photonics are addressed and evaluated. The discussion includes the fundamental components of coherent data links, namely the optical components, fiber link and transceivers. As a major component of these links, a monolithic silicon photonic BiCMOS O-band coherent receiver is evaluated for its potential performance and compared to an analogous C-band device.