Investigation of Waveguide Propagation of Terahertz Signal with Different Polarization Angle and Twisting Rate for Terabit DSL Application

When the demand for higher data rates grows, various telecommunications technologies are proposed; for these cases, the terabit DSL is investigated. Terabit DSLs provides solutions to the inevitable bottleneck that future wireless systems encounter. However, the propagation loss in twisted pairs becomes a massive concern in terabit DSL. Besides the attenuation, propagation characteristics at terahertz frequencies in twisted pair are not much explored by the researcher. Therefore, terahertz signal propagation characteristics in a waveguide based on surface plasmonic are investigated in this project by using simulation software CST MICROWAVE STUDIO. A circular waveguide with radius of 0.25 mm and length of 20 mm respectively has been simulated in between 360 GHz to 380 GHz. The reflection coefficient and transmission coefficient analysis of the circular waveguide are investigated in terms of the polarization angles and twisting rate. Based on the simulated results, it is discovered that the polarization angle influences the reflection coefficient and transmission coefficient of the circular waveguide. When the polarization angle difference is 90 degrees, it has the worst reflection. The circular waveguide with a polarization angle difference of 0 degrees and 180 degrees, it has the best transmission coefficient. The transmission coefficient of the circular waveguide, on the other hand, is unaffected by the twisting rate. Even though the highest twisting rate that has the highest transmission coefficient, it is still lower than 3 dB. Besides, the higher the twisting rate the lesser the number of resonances for the circular waveguide

Propagation Characteristics in a Circular Waveguide for Feasibility Study of Terabit DSL

Due to the demand for higher data rates and greater download speeds by users and increasing number of deployed devices providing content-rich data, new cost-effective technologies which utilizes the concept of waveguides over copper that can enable the realization of terabit DSL need to be explored to meet the required demands. This paper presents the propagation characteristics of circular waveguide which include reflection/transmission coefficient, attenuation coefficient and surface current. The design and simulation process have been carried out using CST Microwave Studios at the frequency of 100GHz to 300GHz. The circular waveguide is varied for various radius and length to observe for the respective propagation characteristics. Based on the result, it is shown that the reflection coefficient decreases with the increase in radius and length and it is below -50dB. Besides, with the increase in frequency, the transmission coefficient shows that the waveguide is able to achieve 100% transmission (0dB) at 200GHz with the increase in radius and length. Moreover, the attenuation coefficient of the waveguide is low which is about 0.0022dB/mm and maximum surface current intensity of 81.5556A/m. The results obtained can be considered the first step on understanding the propagation characteristics of waveguide at terahertz frequency range towards the realization of Terabit DSL

Packet Transactions: High-level Programming for Line-Rate Switches

Many algorithms for congestion control, scheduling, network measurement, active queue management, security, and load balancing require custom processing of packets as they traverse the data plane of a network switch. To run at line rate, these data-plane algorithms must be in hardware. With today's switch hardware, algorithms cannot be changed, nor new algorithms installed, after a switch has been built. This paper shows how to program data-plane algorithms in a high-level language and compile those programs into low-level microcode that can run on emerging programmable line-rate switching chipsets. The key challenge is that these algorithms create and modify algorithmic state. The key idea to achieve line-rate programmability for stateful algorithms is the notion of a packet transaction : a sequential code block that is atomic and isolated from other such code blocks. We have developed this idea in Domino, a C-like imperative language to express data-plane algorithms. We show with many examples that Domino provides a convenient and natural way to express sophisticated data-plane algorithms, and show that these algorithms can be run at line rate with modest estimated die-area overhead.Comment: 16 page

A Rigorous Solution to Electromagnetic Wave Diffraction by Junctions of Impedance and Semitransparent Surfaces

Recent studies of surface-wave-based waveguides for terahertz (THz) imaging and spectroscopy have displayed some interest in investigating surface-wave diffraction by junctions of surfaces with different boundary conditions. Generally, many practically applicable surfaces for THz surface waveguides can be described using nontransparent or semitransparent impedance boundary conditions. In this communication, we find rigorous solutions to electromagnetic wave diffraction by the junction of a nontransparent impedance wedge and a semitransparent half-plane, as well as the junction of two semitransparent half-planes. Generalized semitransparent boundary conditions characterize these semitransparent surfaces

Fully Programming the Data Plane: A Hardware/Software Approach

Les réseaux définis par logiciel — en anglais Software-Defined Networking (SDN) — sont apparus ces dernières années comme un nouveau paradigme de réseau. SDN introduit une séparation entre les plans de gestion, de contrôle et de données, permettant à ceux-ci d’évoluer de manière indépendante, rompant ainsi avec la rigidité des réseaux traditionnels. En particulier, dans le plan de données, les avancées récentes ont porté sur la définition des langages de traitement de paquets, tel que P4, et sur la définition d’architectures de commutateurs programmables, par exemple la Protocol Independent Switch Architecture (PISA). Dans cette thèse, nous nous intéressons a l’architecture PISA et évaluons comment exploiter les FPGA comme plateforme de traitement efficace de paquets. Cette problématique est étudiée a trois niveaux d’abstraction : microarchitectural, programmation et architectural. Au niveau microarchitectural, nous avons proposé une architecture efficace d’un analyseur d’entêtes de paquets pour PISA. L’analyseur de paquets utilise une architecture pipelinée avec propagation en avant — en anglais feed-forward. La complexité de l’architecture est réduite par rapport à l’état de l’art grâce a l’utilisation d’optimisations algorithmiques. Finalement, l’architecture est générée par un compilateur P4 vers C++, combiné à un outil de synthèse de haut niveau. La solution proposée atteint un débit de 100 Gb/s avec une latence comparable à celle d’analyseurs d’entêtes de paquets écrits à la main. Au niveau de la programmation, nous avons proposé une nouvelle méthodologie de conception de synthèse de haut niveau visant à améliorer conjointement la qualité logicielle et matérielle. Nous exploitons les fonctionnalités du C++ moderne pour améliorer à la fois la modularité et la lisibilité du code, tout en conservant (ou améliorant) les résultats du matériel généré. Des exemples de conception utilisant notre méthodologie, incluant pour l’analyseur d’entête de paquets, ont été rendus publics.----------ABSTRACT: Software-Defined Networking (SDN) has emerged in recent years as a new network paradigm to de-ossify communication networks. Indeed, by offering a clear separation of network concerns between the management, control, and data planes, SDN allows each of these planes to evolve independently, breaking the rigidity of traditional networks. However, while well spread in the control and management planes, this de-ossification has only recently reached the data plane with the advent of packet processing languages, e.g. P4, and novel programmable switch architectures, e.g. Protocol Independent Switch Architecture (PISA). In this work, we focus on leveraging the PISA architecture by mainly exploiting the FPGA capabilities for efficient packet processing. In this way, we address this issue at different abstraction levels: i) microarchitectural; ii) programming; and, iii) architectural. At the microarchitectural level, we have proposed an efficient FPGA-based packet parser architecture, which is a major PISA’s component. The proposed packet parser follows a feedforward pipeline architecture in which the internal microarchitectural has been meticulously optimized for FPGA implementation. The architecture is automatically generated by a P4- to-C++ compiler after several rounds of graph optimizations. The proposed solution achieves 100 Gb/s line rate with latency comparable to hand-written packet parsers. The throughput scales from 10 Gb/s to 160 Gb/s with moderate increase in resource consumption. Both the compiler and the packet parser codebase have been open-sourced to permit reproducibility. At the programming level, we have proposed a novel High-Level Synthesis (HLS) design methodology aiming at improving software and hardware quality. We have employed this novel methodology when designing the packet parser. In our work, we have exploited features of modern C++ that improves at the same time code modularity and readability while keeping (or improving) the results of the generated hardware. Design examples using our methodology have been publicly released

Exploiting surface plasmon with dielectric coating in copper wires waveguide for the propagation of terahertz waves

Recently, metallic wires have gained popularity for utilization as waveguides in propagating sub-THz and THz waves through surface plasmonic polaritons (SPPs). Single and double metallic wire waveguides have demonstrated the ability to propagate these high frequencies with minimal loss and nearly zero dispersion. However, wires typically installed commercially are often coated with dielectric material. Therefore, this paper investigated the effects of using two and four metallic copper wires, both with and without dielectric coating. The impact of various gap distances on different propagation characteristics was also analyzed. Computer Simulation Technology (CST) Microwave Studio was employed in this study for electromagnetic simulations of both uncoated and coated configurations of two and four wires. The introduction of a dielectric coating led to an enhancement in reducing conductor losses and improving energy confinement, with the goal of enhancing the overall efficiency of waveguide signal propagation

Exploiting surface plasmon with dielectric coating in copper wires waveguide for the propagation of terahertz waves

Recently, metallic wires have gained popularity for utilization as waveguides in propagating sub-THz and THz waves through surface plasmonic polaritons (SPPs). Single and double metallic wire waveguides have demonstrated the ability to propagate these high frequencies with minimal loss and nearly zero dispersion. However, wires typically installed commercially are often coated with dielectric material. Therefore, this paper investigated the effects of using two and four metallic copper wires, both with and without dielectric coating. The impact of various gap distances on different propagation characteristics was also analyzed. Computer Simulation Technology (CST) Microwave Studio was employed in this study for electromagnetic simulations of both uncoated and coated configurations of two and four wires. The introduction of a dielectric coating led to an enhancement in reducing conductor losses and improving energy confinement, with the goal of enhancing the overall efficiency of waveguide signal propagation

Interaction between surface waves on wire lines.

This paper investigates coupling between electromagnetic surface waves on parallel wires. Finite-element method (FEM)-based and analytic models are developed for single- and double-wire Sommerfeld and Goubau lines. Models are validated via measurements for Goubau lines and a comparison between the analytic and the FEM-based computations for coupled Sommerfeld- and Goubau-type lines is carried out. The measurements and calculations show remarkable agreement. The FEM-based and analytic models match remarkably well too. The results exhibit new favourable effects for surface waves propagation over multiple conductors. The short-range behaviour of the coupled wires and, consequently, the existence of an optimum separation of coupled wires is one of the most significant findings of this paper. We comment on the relevance of our results, particularly in relation to applications of high bandwidth demands and cross-coupling effects

Fifty Years of Noise Modeling and Mitigation in Power-Line Communications.

Building on the ubiquity of electric power infrastructure, power line communications (PLC) has been successfully used in diverse application scenarios, including the smart grid and in-home broadband communications systems as well as industrial and home automation. However, the power line channel exhibits deleterious properties, one of which is its hostile noise environment. This article aims for providing a review of noise modeling and mitigation techniques in PLC. Specifically, a comprehensive review of representative noise models developed over the past fifty years is presented, including both the empirical models based on measurement campaigns and simplified mathematical models. Following this, we provide an extensive survey of the suite of noise mitigation schemes, categorizing them into mitigation at the transmitter as well as parametric and non-parametric techniques employed at the receiver. Furthermore, since the accuracy of channel estimation in PLC is affected by noise, we review the literature of joint noise mitigation and channel estimation solutions. Finally, a number of directions are outlined for future research on both noise modeling and mitigation in PLC