Performance evaluation of currently available VLSI implementations satisfying U-interface requirements for an ISDN in South Africa.

A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering.This project report examines the performance of three VLSI U-interface implementations satisfying the requirements of Basic Access on an ISDN. The systems evaluated are the Intel 89120,Siemens PEB2090 and STC DSP144, operating on 2BIQ, MMS4J and SU32 line codes respectively. Before evaluating the three abovementioned systems, a review of the underlying principles of U-interface technology is presented. Included in the review are aspects of transmission line theory, line coding, echo-cancellation, decision feedback equalisation, and pulse density modulation. The functional specifications of the three systems are then presented followed by a practical evaluation of each system. As an aid to testing the transmission systems, an evaluation board has been designed and built. The latter provides the necessary functionality to correctly activate each system, as well as the appropriate interfacing requirements for the error-rate tester. The U-interface transmission systems are evaluated on a number of test-loops, comprising sections of cable varying in length and gauge. Additionally, impairments are injected into data-carrying cables, in order to test the performance of each system in the presence of noise. The results of each test are recorded and analysed. Finally, a recommendation is made in favour of the 2BIQ U-interface. It is shown to offer superior transmission performance, at the expense of a slightly higher transmit-power level.Andrew Chakane 201

Quality of Service optimisation framework for Next Generation Networks

Within recent years, the concept of Next Generation Networks (NGN) has become widely accepted within the telecommunication area, in parallel with the migration of telecommunication networks from traditional circuit-switched technologies such as ISDN (Integrated Services Digital Network) towards packet-switched NGN. In this context, SIP (Session Initiation Protocol), originally developed for Internet use only, has emerged as the major signalling protocol for multimedia sessions in IP (Internet Protocol) based NGN. One of the traditional limitations of IP when faced with the challenges of real-time communications is the lack of quality support at the network layer. In line with NGN specification work, international standardisation bodies have defined a sophisticated QoS (Quality of Service) architecture for NGN, controlling IP transport resources and conventional IP QoS mechanisms through centralised higher layer network elements via cross-layer signalling. Being able to centrally control QoS conditions for any media session in NGN without the imperative of a cross-layer approach would result in a feasible and less complex NGN architecture. Especially the demand for additional network elements would be decreased, resulting in the reduction of system and operational costs in both, service and transport infrastructure. This thesis proposes a novel framework for QoS optimisation for media sessions in SIP-based NGN without the need for cross-layer signalling. One key contribution of the framework is the approach to identify and logically group media sessions that encounter similar QoS conditions, which is performed by applying pattern recognition and clustering techniques. Based on this novel methodology, the framework provides functions and mechanisms for comprehensive resource-saving QoS estimation, adaptation of QoS conditions, and support of Call Admission Control. The framework can be integrated with any arbitrary SIP-IP-based real-time communication infrastructure, since it does not require access to any particular QoS control or monitoring functionalities provided within the IP transport network. The proposed framework concept has been deployed and validated in a prototypical simulation environment. Simulation results show MOS (Mean Opinion Score) improvement rates between 53 and 66 percent without any active control of transport network resources. Overall, the proposed framework comes as an effective concept for central controlled QoS optimisation in NGN without the need for cross-layer signalling. As such, by either being run stand-alone or combined with conventional QoS control mechanisms, the framework provides a comprehensive basis for both the reduction of complexity and mitigation of issues coming along with QoS provision in NGN

Design and implementation aspects of open source next generation networks (NGN) test-bed software toolkits

Informations- und Kommunikationstechnologien bilden seit langem das immer wichtiger werdende Rückgrat der weltweiten Wirtschaft und Telekommunikation, in der speziell Telekommunikationsnetze und -dienste einen elementaren Anteil tragen. Durch die Konvergenz von Telekommunikations- und Internettechnologien hat sich die Telekommunikationslandschaft in der letzten Dekade drastisch verändert. Bislang geschlossene Telekommunikationsumgebungen haben sich imWandel zum sogenannten Next Generation Network (NGN) hinsichtlich unterstützter Zugangsnetztechnologien und angebotener multimedialer Anwendungen sowie der eingesetzten Protokolle und Dienste zu komplexen, hochdynamischen, Multi-Service Infrastrukturen gewandelt. Die Kontrollschicht solcher NGNs ist dabei von übergeordneter Bedeutung, da diese zwischen den Zugangsnetzen und den Anwendungen sitzt. Der Einsatz und die Optimierung des IP-Multimedia Subsystem (IMS) wurde in diesem Kontext Jahrelang erforscht und diskutiert und es repräsentiert heute die weltweit anerkannte Kontrollplattform für feste und mobile Telekommunikationsnetze. Die Forschung an Protokollen und Diensten in diesen NGN Umgebungen ist aufgrund der Konvergenz von Technologien, Anwendungen und Business Modellen sowie der hohen Dynamik aber kurzen Innovationszyklen hochkomplex. Der frühzeitigen Zugang zu herstellerunabhängigen – aber dicht an der Produktwelt angelehnten - Validierungsinfrastrukturen, sogenannten offenen Technologietest-beds, kurz Test-beds, ist daher für Forschungs- und Entwicklungsabteilungen unerlässlich Die vorliegende Dissertation beschreibt die umfangreiche Forschungsarbeit des Autors auf dem Gebiet der offenen NGN Test-beds über die letzten neun Jahre und konzentriert sich dabei auf Entwurf, Entwicklung und Bereitstellung des Open Source IMS Core Projekt, das seit Jahren die Grundlage für eine Vielzahl von NGN Test-beds und zahllose NGN Forschungs- und Entwicklungsprojekte im akademischen als auch Industrienahen Umfeld rund um den Globus darstellt. Dabei wird ein großer Schwerpunkt auf die Anforderungen hinsichtlich Flexibilität, Leistung, Funktionalitätsumfang und Interoperabilität, sowie elementare Designprinzipien von Test-bedwerkzeugen gelegt. Die Arbeit beschreibt und bewertet darüberhinaus den Einsatz von Open Source Prinzipien und veranschaulicht die Vorteile dieses Ansatzes hinsichtlich Einfluss und Nachhaltigkeit der Forschung anhand des Aufbaus einer globalen Open Source IMS Core (OpenIMSCore) Forschungs-Community. Außerdem veranschaulicht die Arbeit zum Ende die Wiederverwendbarkeit der wesentlichen angewendeten Designprinzipien an anderen maßgeblich durch den Autor entwickelten Test-bed Werkzeugen, insbesondere dem Open Evolved Packet Core (OpenEPC) für die nahtlose Integration verschiedener Breitbandnetztechnologien.Information and Communication Technologies provide for a long time already the backbone of telecommunication networks, such that communication services represent an elementary foundation of today’s globally connected economy. The telecommunication landscape has experienced dramatic transformations through the convergence of the Telecom and the Internet worlds. The previously closed telecommunication domain is currently transforming itself through the so-called NGN evolution into a highly dynamic multiservice infrastructure, supporting rich multimedia applications, as well as providing comprehensive support for various access technologies. The control layer of such NGNs is then of paramount importance, as representing the convergent mediator between access and services. The use and the optimization of the IP-Multimedia Subsystem (IMS) was researched and considered in this domain for many years now, such that today it represents the world-wide recognized control platform for fixed and mobile NGNs. Research on protocols and services for such NGN architectures, due to the convergence of technologies, applications and business models, as well as for enabling highly dynamic and short innovation cycles, is highly complex and requires early access to vendor independent - yet close to real life systems - validation environments, the so-called open technology test-beds. The present thesis describes the extensive research of the author over the last nine years in the field of open NGN test-beds. It focuses on the design, development and deployment of the Open Source IMS Core project, which represents since years the foundation of numerous NGN test-beds and countless NGN Research & Development projects in the academia as well as the industry domain around the globe. A major emphasis is given for ensuring flexibility, performance, reference functionality and inter-operability, as well as satisfying elementary design principles of such test-bed toolkits. The study also describes and evaluates the use of Open Source principles, highlighting the advantages of using it in regard to the creation, impact and sustainability of a global OpenIMSCore research community. Moreover, the work documents that the essential design principles and methodology employed can be reused in a generic way to create test-bed toolkits in other technology domains. This is shown by introducing the OpenEPC project, which provides for seamless integration of different mobile broadband technologies

Study, Analysis and Modeling of IP Multimedia systems on next generation networks providing mobile and fixed multimedia services

Not availabl

Via transition modeling and charge replenishment of the power delivery network in multilayer PCBs

In the first article of this thesis, the charge delivery in the power distribution network for printed circuit board has been analyzed in the time-domain. Performing all the simulations and analyzing the PDN physics and modeling, I contributed to a better understanding of the time-domain decoupling mechanism. The second paper studies the noise coupling sing a segmentation approach combined with a via-to-antipad capacitance model and a plane-pair cavity model. Building equivalent circuit models as well as analyzing design strategies, I contributed to a new approach for the PDN analysis in multilayer PCBs. The third article discusses how to estimate the amount of current needed for large ICs and how to evaluate the amount of noise voltage due to this current draw. After accurate discussion of the design strategies, I modeled and simulated the free evolution of a charged PCB with and without decoupling capacitors. The depletion of charges stored between the power buses in time and frequency-domain has been investigated as a function of the plane thickness, SMT decoupling closeness in the fourth paper. With my contribution, the time and frequency-domain in the PDN have been related using circuit approach. In the fifth paper, I analyzed a 26-layer printed circuit board performing milling, measurements and building circuit models. It is the first time that the segmentation approach has been used for differential geometry. In addition, Debye materials have been implemented in the cavity model --Abstract, page iv

NASA patent abstracts bibliography: A continuing bibliography. Section 1: Abstracts (supplement 25)

Abstracts are provided for 102 patents and patent applications entered into the NASA scientific and technical information system during the period January 1984 through June 1984. Each entry consists of a citation, an abstract, and in most cases, a key illustration selected from the patent or patent application

A definition study of an Advanced Data Collection and Location System (ADCLS)

The technical and economic advantages of developing an Advanced Data Collection and Location System (ADCLS) to operate within the Earth Observation System (EOS) planned for Polar Platform, as a replacement and/or augmentation of the existing ARGOS data collection system were assessed. The cost/effectiveness of ADCLS with respect to ARGOS hinges on the traffic and quality of service demand of the future user constituency

Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)

Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression

Network-based IP flow mobility support in 3GPPs evolved packet core

Includes bibliographical references.Mobile data traffic in cellular networks has increased tremendously in the last few years. Due to the costs associated with licensed spectrum, Mobile Network Operators (MNOs) are battling to manage these increased traffic growths. Offloading mobile data traffic to alternative low cost access networks like Wi-Fi has been proposed as a candidate solution to enable MNOs to alleviate congestion from the cellular networks. This dissertation investigates an offloading technique called IP flow mobility within the 3rd Generation Partnership Project (3GPP) all-IP mobile core network, the Evolved Packet Core (EPC). IP flow mobility would enable offloading a subset of the mobile user‟s traffic to an alternative access network while allowing the rest of the end-user‟s traffic to be kept in the cellular access; this way, traffic with stringent quality of service requirements like Voice over Internet Protocol (VoIP) would not experience service disruption or interruption when offloaded. This technique is different from previous offloading techniques where all the end-user‟s traffic is offloaded. IP flow mobility functionality can be realised with either host- or network-based mobility protocols. The recommended IP flow mobility standard of 3GPP is based on the host-based mobility solution, Dual-Stack Mobile IPv6. However, host-based mobility solutions have drawbacks like long handover latencies and produce signaling overhead in the radio access networks, which could be less appealing to MNOs. Network-based mobility solutions, compared to the host-based mobility solutions, have reduced handover latencies with no signaling overhead occurring in the radio access network. Proxy Mobile IPv6 is a networkbased mobility protocol adapted by 3GPP for mobility in the EPC. However, the standardisation of the Proxy Mobile IPv6-based IP flow mobility functionality is still ongoing within 3GPP. A review of related literature and standardisation efforts reveals shortcomings with the Proxy Mobile IPv6 mobility protocol in supporting IP flow mobility. Proxy Mobile IPv6 does not have a mechanism that would ensure session continuity during IP flow handoffs or a mechanism enabling controlling of the forwarding path of a particular IP flow i.e., specifying the access network for the IP flow. The latter mechanism is referred to as IP flow information management and flow-based routing. These mechanisms represent the basis for enabling the IP flow mobility functionality. To address the shortcomings of Proxy Mobile IPv6, this dissertation proposes vi enhancements to the protocol procedures to enable the two mechanisms for IP flow mobility functionality. The proposed enhancements for the session continuity mechanism draw on work in related literature and the proposed enhancements for the IP flow information management and flow-based routing mechanism are based on the concepts used in the Dual- Stack Mobile IPv6 IP flow mobility functionality. Together the two mechanisms allow the end-user to issue requests on what access network a particular IP flow should be routed, and ensure that the IP flows are moved to the particular access network without session discontinuity

Component-Based Formal Analysis of 5G-AKA: Channel Assumptions and Session Confusion

The 5G mobile telephony standards are nearing completion; upon adoption these will be used by billions across the globe. Ensuring the security of 5G communication is of the utmost importance, building trust in a critical component of everyday life and national infrastructure. We perform fine-grained formal analysis of 5G’s main authentication and key agreement protocol (AKA), and provide the first models to explicitly consider all parties defined by the protocol specification. Our analysis reveals that the security of 5G-AKA critically relies on unstated assumptions on the inner workings of the underlying channels. In practice this means that following the 5G-AKA specification, a provider can easily and ‘correctly’ implement the standard insecurely, leaving the protocol vulnerable to a security-critical race condition. We provide the first models and analysis considering component and channel compromise in 5G, whose results further demonstrate the fragility and subtle trust assumptions of the 5G-AKA protocol. We propose formally verified fixes to the encountered issues, and have worked with 3GPP to ensure these fixes are adopted