Embedded System Optimization of Radar Post-processing in an ARM CPU Core

Algorithms executed on the radar processor system contributes to a significant performance bottleneck of the overall radar system. One key performance concern is the latency in target detection when dealing with hard deadline systems. Research has shown software optimization as one major contributor to radar system performance improvements. This thesis aims at software optimizations using a manual and automatic approach and analyzing the results to make informed future decisions while working with an ARM processor system. In order to ascertain an optimized implementation, a question put forward was whether the algorithms on the ARM processor could work with a 6-antenna implementation without a decline in the performance. However, an answer would also help project how many additional algorithms can still be added without performance decline. The manual optimization was done based on the quantitative analysis of the software execution time. The manual optimization approach looked at the vectorization strategy using the NEON vector register on the ARM CPU to reimplement the initial Constant False Alarm Rate(CFAR) Detection algorithm. An additional optimization approach was eliminating redundant loops while going through the Range Gates and Doppler filters. In order to determine the best compiler for automatic code optimization for the radar algorithms on the ARM processor, the GCC and Clang compilers were used to compile the initial algorithms and the optimized implementation on the radar post-processing stage. Analysis of the optimization results showed that it is possible to run the radar post-processing algorithms on the ARM processor at the 6-antenna implementation without system load stress. In addition, the results show an excellent headroom margin based on the defined scenario. The result analysis further revealed that the effect of dynamic memory allocation could not be underrated in situations where performance is a significant concern. Additional statements from the result demonstrated that the GCC and Clang compiler has their strength and weaknesses when used in the compilation. One limiting factor to note on the optimization using the NEON register is the sample size’s effect on the optimization implementation. Although it fits into the test samples used based on the defined scenario, there might be varying results in varying window cell size situations that might not necessarily improve the time constraints

Co-design of Security Aware Power System Distribution Architecture as Cyber Physical System

The modern smart grid would involve deep integration between measurement nodes, communication systems, artificial intelligence, power electronics and distributed resources. On one hand, this type of integration can dramatically improve the grid performance and efficiency, but on the other, it can also introduce new types of vulnerabilities to the grid. To obtain the best performance, while minimizing the risk of vulnerabilities, the physical power system must be designed as a security aware system. In this dissertation, an interoperability and communication framework for microgrid control and Cyber Physical system enhancements is designed and implemented taking into account cyber and physical security aspects. The proposed data-centric interoperability layer provides a common data bus and a resilient control network for seamless integration of distributed energy resources. In addition, a synchronized measurement network and advanced metering infrastructure were developed to provide real-time monitoring for active distribution networks. A hybrid hardware/software testbed environment was developed to represent the smart grid as a cyber-physical system through hardware and software in the loop simulation methods. In addition it provides a flexible interface for remote integration and experimentation of attack scenarios. The work in this dissertation utilizes communication technologies to enhance the performance of the DC microgrids and distribution networks by extending the application of the GPS synchronization to the DC Networks. GPS synchronization allows the operation of distributed DC-DC converters as an interleaved converters system. Along with the GPS synchronization, carrier extraction synchronization technique was developed to improve the system’s security and reliability in the case of GPS signal spoofing or jamming. To improve the integration of the microgrid with the utility system, new synchronization and islanding detection algorithms were developed. The developed algorithms overcome the problem of SCADA and PMU based islanding detection methods such as communication failure and frequency stability. In addition, a real-time energy management system with online optimization was developed to manage the energy resources within the microgrid. The security and privacy were also addressed in both the cyber and physical levels. For the physical design, two techniques were developed to address the physical privacy issues by changing the current and electromagnetic signature. For the cyber level, a security mechanism for IEC 61850 GOOSE messages was developed to address the security shortcomings in the standard

The Telecommunications and Data Acquisition Progress Journal

Developments in Earth based radio technology are reported. The Deep Space Network, radio interferometry, and observation of celestial radio sources are covered

Distributed photovoltaic systems: Utility interface issues and their present status

Major technical issues involving the integration of distributed photovoltaics (PV) into electric utility systems are defined and their impacts are described quantitatively. An extensive literature search, interviews, and analysis yielded information about the work in progress and highlighted problem areas in which additional work and research are needed. The findings from the literature search were used to determine whether satisfactory solutions to the problems exist or whether satisfactory approaches to a solution are underway. It was discovered that very few standards, specifications, or guidelines currently exist that will aid industry in integrating PV into the utility system. Specific areas of concern identified are: (1) protection, (2) stability, (3) system unbalance, (4) voltage regulation and reactive power requirements, (5) harmonics, (6) utility operations, (7) safety, (8) metering, and (9) distribution system planning and design

Powerline Kommunikation: Wesentliche Technologien um PLC in CE-Geräte zu integrieren

In-house PLT (Powerline Telecommunication) enables new and highly convenient networking functions without the need for additional cables on mains-powered devices. Since wireless networks are not able to reach sufficient throughput between different rooms or even floors, PLC is considered to be the ideal backbone home network medium, providing complementary and seamless interaction with wireless networks. The need to communicate information is not new. The historical overview of this thesis compares the development of PLT to radio broadcast technologies. The consumer expects technologies to operate without interferences. Today, there are coexistence problems between these two technologies. Why does this happens, and how the problems can be resolved are the main issues of this thesis. Initial calculations of the channel capacity provide encouraging results for using the mains cabling as a communication medium. Chapter 3 forecasts how PLT modems could develop in the future. The usage of frequencies above 30 MHz will increase the throughput rate. Next, the utilization of the 3rd wire (the protective earth) for communication enhances the coverage and the reliability of powerline transmissions. The reception of common mode signals and the usage of MIMO technologies enable 8 transmission paths between one pair of outlets, which improves the performance of the bad, strongly attenuated channels. Today, the main challenge for the mass deployment of PLT is the lack of harmonized international standards on interoperability and electromagnetic interference. The absence of a standard results in the undesirable situation of PLT modems interfering with technologies from different vendors and also with radio applications. Solutions for solving these problems are given in chapter 4 and chapter 5. The approach of ‘Smart Notching’ - monitoring the existence of receivable radio broadcast stations at the time and location where a PLT modem is operating, received wide resonance in the PLT and radio broadcast communities. ‘Smart Notching’, also called ‘Dynamic Notching’ or ‘Adaptive Notching’ is considered to be the key factor in solving the endless discussions about the interferences to HF radio broadcast. Details on the creation of ETSI TS 102 578 and the implementation of a demonstrator system is documented in chapter 5. Field tests conducted together with the EBU verified the efficiency of the concept. The jointly executed tests by representatives from the radio broadcast and the PLT communities became a historical event which brought the two technologies, radio receivers and PLT modems, back into one house. Finally, a vision of the future coordination of EMC and conclusions are presented.Heutige Modems zur Powerline Telekommunikation (PLT) können im Betrieb den Empfang von Kurzwellen-Rundfunk beeinträchtigen, wenn Modem und Rundfunk-Empfänger in unmittelbarer Nachbarschaft betrieben werden. Eine neue Generation von PLT Modems, in denen das Konzept von 'Smart Notching' - dem intelligenten Einfügen von Lücken in das Kommunikationsspektrum - implementiert ist, zeigt keine Interferenzen mit dem Empfang von Rundfunkdiensten. Das Rauschen auf der Niederspannungsinstallation enthält neben sonstigen Signalen - durch andere Geräte hervorgerufen - aufgrund der Antennenwirkung Information über Rundfunksender. Beim ‚Smart Notching’ erkennen PLT Modems am Betriebsort die Existenz von Rundfunksignalen, indem sie das Signalspektrum auf der Netzleitung messen. Die Echtzeit- Bewertung der aktuellen Situation am Betriebsort ermöglicht eine Adaption des PLT Systems. Damit wird die Elektromagnetische Verträglichkeit nicht a priori (zum Herstellungs-Zeitpunkt) durch Schirmung oder eine globale Reduktion des Sendepegels, sondern durch Design des Verfahrens (welches während des Betriebs angewendet wird) hergestellt. Diese Doktorarbeit beschreibt nach einem kurzen Überblick zur Historie des Rundfunks und der Datenübertragung über das Energieverteilnetz Messungen zur Ermittlung der theoretischen Kanalkapazität. Anschließend wird ein Ausblick gegeben, wohin sich zukünftige PLT Modems entwickeln werden. Dies sind vor allem der Frequenzbereich oberhalb von 30 MHz sowie die Nutzung der dritten Kupferader in den Netzleitungen: der Schutzerde. Die Verwendung von MIMO-Algorithmen (aus der kabellosen Funkübertragung (z.B. WiFi) bereits bekannt) verbessert vor allem die Wahrscheinlichkeit, eine hohe Datenrate im Gebäude sicher zu verteilen. Sorge bereitet bei PLT ebenfalls die Koexistenz mit weiteren PLT-Systemen, sowie zu xDSL. Hierfür wird ein Vorschlag gemacht, um die Interferenzen zu nicht kompatiblen PLToder DSL-Systemen zu vermeiden, ohne dass die Systeme sich gegenseitig gezielt Informationen zusenden. Das bereits oben erwähnte Konzept des ‚Smart Notching’ wird detailliert erläutert und die Implementierung eines Demonstrators auf FPGA-Basis dokumentiert. Abschließend wird noch beschrieben, wie ‚Smart Notching’ gemeinsam mit der EBU getestet wurde und wie es seinen Weg in die Welt der Standardisierung gefunden hat. Der Veröffentlichung des Standards ETSI TS 102 578 wurde im Juli 2008 einstimmig von ETSI PLT zugestimmt

Circuit and System Level Design Optimization for Power Delivery And Management

As the VLSI technology scales to the nanometer scale, power consumption has become a critical design concern of VLSI circuits. Power gating and dynamic voltage and frequency scaling (DVFS) are two effective power management techniques that are widely utilized in modern chip designs. Various design challenges merge with these power management techniques in nanometer VLSI circuits. For example, power gating introduces unique power integrity issues and trade-offs between switching noise and rush current noise. Assuring power integrity and achieving power efficiency are two highly intertwined design challenges. In addition, these trade-offs significantly vary with the supply voltage. It is difficult to use conventional power-gated power delivery networks (PDNs) to fully meet the involved conflicting design constraints while maximizing power saving and minimizing supply noise. The DVFS controller and the DC-DC power converter are two highly intertwining enablers for DVFS-based systems. However, traditional DVFS techniques treat the design optimizations of the two as separate tasks, giving rise to sub-optimal designs. To address the above research challenges, we propose several circuit and system level design optimization techniques in this dissertation. For power-gated PDN designs, we propose systemic decoupling capacitor (decap) optimization strategies that optimally trade-off between power integrity and leakage saving. First, new global decap and re-routable decap design concepts are proposed to relax the tight interaction between power integrity and leakage power saving of power-gated PDN at a single supply voltage level. Furthermore, we propose to leverage re-routable decaps to provide flexible decap allocation structures to better suit multiple supply voltage levels. The proposed strategies are implemented in an automatic design flow for choosing optimal amount of local decaps, global decaps and re-routable decaps. The proposed techniques significantly increase leakage saving without jeopardizing power integrity. The flexible decap allocations enabled by re-routable decaps lead to optimal design trade-offs for PDNs operating with two supply voltage levels. To improve the effectiveness of DVFS, we analyze the drawbacks of circuit-level only and policy-level only optimizations and the promising opportunities resulted from the cross-layer co-optimization of the DC-DC converter and online learning based DVFS polices. We present a cross-layer approach that optimizes transition time, area, energy overhead of the DC-DC converter along with key parameters of an online learning DVFS controller. We systematically evaluate the benefits of the proposed co-optimization strategy based on several processor architectures, namely single and dual-core processors and processors with DVFS and power gating. Our results indicate that the co-optimization can introduce noticeable additional energy saving without significant performance degradation

The Deep Space Network, volume 3 Progress report, Mar. - Apr. 1971

Deep Space Network telecommunication and ground support equipment for planetary and interplanetary flight project

Multi-Antenna Techniques for Next Generation Cellular Communications

Future cellular communications are expected to offer substantial improvements for the pre- existing mobile services with higher data rates and lower latency as well as pioneer new types of applications that must comply with strict demands from a wider range of user types. All of these tasks require utmost efficiency in the use of spectral resources. Deploying multiple antennas introduces an additional signal dimension to wireless data transmissions, which provides a significant alternative solution against the plateauing capacity issue of the limited available spectrum. Multi-antenna techniques and the associated key enabling technologies possess unquestionable potential to play a key role in the evolution of next generation cellular systems. Spectral efficiency can be improved on downlink by concurrently serving multiple users with high-rate data connections on shared resources. In this thesis optimized multi-user multi-input multi-output (MIMO) transmissions are investigated on downlink from both filter design and resource allocation/assignment points of view. Regarding filter design, a joint baseband processing method is proposed specifically for high signal-to-noise ratio (SNR) conditions, where the necessary signaling overhead can be compensated for. Regarding resource scheduling, greedy- and genetic-based algorithms are proposed that demand lower complexity with large number of resource blocks relative to prior implementations. Channel estimation techniques are investigated for massive MIMO technology. In case of channel reciprocity, this thesis proposes an overhead reduction scheme for the signaling of user channel state information (CSI) feedback during a relative antenna calibration. In addition, a multi-cell coordination method is proposed for subspace-based blind estimators on uplink, which can be implicitly translated to downlink CSI in the presence of ideal reciprocity. Regarding non-reciprocal channels, a novel estimation technique is proposed based on reconstructing full downlink CSI from a select number of dominant propagation paths. The proposed method offers drastic compressions in user feedback reports and requires much simpler downlink training processes. Full-duplex technology can provide up to twice the spectral efficiency of conventional resource divisions. This thesis considers a full-duplex two-hop link with a MIMO relay and investigates mitigation techniques against the inherent loop-interference. Spatial-domain suppression schemes are developed for the optimization of full-duplex MIMO relaying in a coverage extension scenario on downlink. The proposed methods are demonstrated to generate data rates that closely approximate their global bounds

Third International Symposium on Space Mission Operations and Ground Data Systems, part 2

Under the theme of 'Opportunities in Ground Data Systems for High Efficiency Operations of Space Missions,' the SpaceOps '94 symposium included presentations of more than 150 technical papers spanning five topic areas: Mission Management, Operations, Data Management, System Development, and Systems Engineering. The symposium papers focus on improvements in the efficiency, effectiveness, and quality of data acquisition, ground systems, and mission operations. New technology, methods, and human systems are discussed. Accomplishments are also reported in the application of information systems to improve data retrieval, reporting, and archiving; the management of human factors; the use of telescience and teleoperations; and the design and implementation of logistics support for mission operations. This volume covers expert systems, systems development tools and approaches, and systems engineering issues

All-optical processing systems based on semiconductor optical amplifiers

Doutoramento em Engenharia ElectrotécnicaNesta tese investigam-se e desenvolvem-se dispositivos para processamento integralmente óptico em redes com multiplexagem densa por divisão no comprimento de onda (DWDM). O principal objectivo das redes DWDM é transportar e distribuir um espectro óptico densamente multiplexado com sinais de débito binário ultra elevado, ao longo de centenas ou milhares de quilómetros de fibra óptica. Estes sinais devem ser transportados e encaminhados no domínio óptico de forma transparente, sem conversões óptico-eléctrico-ópticas (OEO), evitando as suas limitações e custos. A tecnologia baseada em amplificadores ópticos de semicondutor (SOA) é promissora graças aos seus efeitos não-lineares ultra-rápidos e eficientes, ao potencial para integração, reduzido consumo de potência e custos. Conversores de comprimento de onda são o elemento óptico básico para aumentar a capacidade da rede e evitar o bloqueio de comprimentos de onda. Neste trabalho, são estudados e analisados experimentalmente métodos para aumentar a largura de banda operacional de conversores de modulação cruzada de ganho (XGM), a fim de permitir a operação do SOA para além das suas limitações físicas. Conversão de um comprimento de onda, e conversão simultânea de múltiplos comprimentos de onda são testadas, usando interferómetros de Mach-Zehnder com SOA. As redes DWDM de alto débito binário requerem formatos de modulação optimizados, com elevada tolerância aos efeitos nefastos da fibra, e reduzida ocupação espectral. Para esse efeito, é vital desenvolver conversores integramente ópticos de formatos de modulação, a fim de permitir a interligação entre as redes já instaladas, que operam com modulação de intensidade, e as redes modernas, que utilizam formatos de modulação avançados. No âmbito deste trabalho é proposto um conversor integralmente óptico de formato entre modulação óptica de banda lateral dupla e modulação óptica de banda lateral residual; este é caracterizado através de simulação e experimentalmente. Adicionalmente, é proposto um conversor para formato de portadora suprimida, através de XGM e modulação cruzada de fase. A interligação entre as redes de transporte com débito binário ultra-elevado e as redes de acesso com débito binário reduzido requer conversão óptica de formato de impulso entre retorno-a-zero (RZ) e não-RZ. São aqui propostas e investigadas duas estruturas distintas: uma baseada em filtragem desalinhada do sinal convertido por XGM; uma segunda utiliza as dinâmicas do laser interno de um SOA com ganho limitado (GC-SOA). Regeneração integralmente óptica é essencial para reduzir os custos das redes. Dois esquemas distintos são utilizados para regeneração: uma estrutura baseada em MZI-SOA, e um método no qual o laser interno de um GC-SOA é modulado com o sinal distorcido a regenerar. A maioria dos esquemas referidos é testada experimentalmente a 40 Gb/s, com potencial para aplicação a débitos binários superiores, demonstrado que os SOA são uma tecnologia basilar para as redes ópticas do futuro.This thesis investigates and develops all-optical processing devices for wavelength division multiplexing networks (DWM) of the future. The ultimate goal of optical networks is to transport and deliver a densely multiplexed spectrum, populated by ultra-high bit rate signals over hundreds or thousands of kilometers of optical fiber. Such signals should be transported and routed transparently in the optical domain, without recurring to optic-electro-optic (OEO) conversions, avoiding its limitations and costs. Semiconductor optical amplifier (SOA) based technology is a promising building block due to its inherent ultra-fast and efficient non-linear effects, potential for integration, low power consumption and cost. Wavelength converters are the basic optical functionality to increase the network throughput and avoid wavelength blocking. Methods to increase the operation bandwidth of cross-gain modulation (XGM) converters are studied and experimentally assessed to enable operation beyond the physical constraints of SOA. Single and multi-wavelength conversion exploiting crossphase modulation (XPM) in Mach-Zehnder interferometer with semiconductor optical amplifiers (MZI-SOA) is tested. High bit rate DWDM networks require optimized modulation formats with enhanced tolerance to fiber impairments and reduced spectral tolerance. As a consequence, it is crucial to develop all-optical modulation formats between legacy on-off-keying networks and networks employing advanced modulation formats. An all-optical format converter between optical double sideband (ODSB) and optical vestigial sideband (OVSB) based on SOA self-phase modulation is proposed and thoroughly characterized by simulations and experimental tests. A converter, which uses a mix of XGM and XPM to allow simultaneous pulse and modulation format conversion to the carrier suppressed format, is proposed. The interface between ultra-high bit rate transport networks and lower bit rate access networks requires optical pulse format conversions between return-tozero (RZ) and non-return-to-zero (NRZ). Two different structures are proposed and investigated. The first is based on detuned filtering of XPM converted signal; while the second uses the dynamics of the internal laser of a gainclamped SOA. All-optical regeneration is one of the most sought functionalities to reduce network costs. Regeneration is achieved in this work through two simple setups: a MZI-SOA based structure, and a method in which the internal laser from a GC-SOA is modulated with the input distorted signal. Most applications are experimentally validated at 40 Gb/s, with potential for even higher bit rates, demonstrating that SOA can be one of the key elements for the next generation of optical networks