High End Performance With Low End Hardware

Massive MIMO (multiple-input–multiple-output) is a multi-antenna technology for cellular wireless communication, where the base station uses a large number of individually controllable antennas to multiplex users spatially. This technology can provide a high spectral efficiency. One of its main challenges is the immense hardware complexity and cost of all the radio chains in the base station. To make massive MIMO commercially viable, inexpensive, low-complexity hardware with low linearity has to be used, which inherently leads to more signal distortion. This thesis investigates how the degenerated linearity of some of the main components—power amplifiers, analog-to-digital converters (ADCs) and low-noise amplifiers—affects the performance of the system, with respect to data rate, power consumption and out-of-band radiation. The main results are: Spatial processing can reduce PAR (peak-to-average ratio) of the transmit signals in the downlink to as low as 0B; this, however, does not necessarily reduce power consumption. In environments with isotropic fading, one-bit ADCs lead to a reduction in effective signal-to-interference-and-noise ratio (SINR) of 4dB in the uplink and four-bit ADCs give a performance close to that of an unquantized system. An analytical expression for the radiation pattern of the distortion from nonlinear power amplifiers is derived. It shows how the distortion is beamformed to some extent, that its gain never is greater than that of the desired signal, and that the gain of the distortion is reduced with a higher number of served users and a higher number of channel taps. Nonlinear low-noise amplifiers give rise to distortion that partly combines coherently and limits the possible SINR. It is concluded that spatial processing with a large number of antennas reduces the impact of hardware distortion in most cases. As long as proper attention is paid to the few sources of coherent distortion, the hardware complexity can be reduced in massive MIMO base stations to overcome the hardware challenge and make massive MIMO commercial reality. Massiv MIMO (eng: multiple-input–multiple-output) är en flerantennsteknologi för cellulär trådlös kommunikation, där basstationen använder ett stort antal individuellt styrbara antenner för att multiplexa användare i rummet. Denna teknologi kan tillhandahålla en hög spektral effektivitet. En av dess främsta utmaningar är den enorma hårdvarukomplexiteten och kostnaden hos basstationens alla radiokedjor. För att massiv MIMO skall bli kommersiellt attraktivt, måste billiga, enkla hårdvarukomponenter med låg linjäritet användas, vilket oundvikligen leder till mer signaldistorsion. Denna avhandling undersöker hur den försämrade linjäriteten hos några av huvudkomponenterna – effektförstärkare, analog-digital-omvandlare (AD-omvandlare) och lågbrusförstärkare – påverkar systemets prestanda, i termer av datatakt, effektförbrukning och utombandsstrålning. Huvudresultaten är: Rumslig signalbehandling kan reducera sändsignalernas toppvärde i nerlänken ända ner till 0dB, vilket dock inte nödvändigtvis minskar effektförbrukningen. I miljöer med isotrop fädning leder enbits-AD-omvandlare till 4dB lägre signal-till-interferens-och-brus-förhållande i upplänken, och fyrabits-AD-omvandlare ger en prestanda nära den ett system utan kvantisering kan uppnå. Ett analytiskt uttryck för strålningsmönstret för distorsionen från icke-linjära effektförstärkare härleds. Det visar hur distorsionen till viss del lobformas, att dess förstärkning aldrig är starkare än förstärkningen för den önskade signalen och att distorsionens förstärkning minskar med ett högre antal betjänade användare och ett högre antal kanaltappar. Icke-linjära lågbrusförstärkare ger upphov distorsion som delvis kombinerar koherent och begränsar det möjliga signal-till-brus-och-interferens-förhållandet. Slutsatsen är att rumslig signalbehandling med ett stort antal antenner reducerar hårdvarudistorsionens inverkan i de flesta fall. Så länge som de få källorna till koherent distorsion ges tillbörlig uppmärksamhet, kan hårdvarukomplexiteten minskas i basstationer för massiv MIMO för att övervinna hårdvaruutmaningen och göra massiv MIMO kommersiell verklighet. ????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????——???????????????——?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????

This guide is a shopping companion for people who wish to build their own desktop computer. It helps you choose which parts are best for you by ensuring compatibility and performance. Features a component overview, valuable rules of thumb, and a quick-lookup reference chart with recommended brands and models

In the last fifty years the world has been completely transformed through the use of IT. We have now reached a new inflection point. This book presents, for the first time, how in-memory data management is changing the way businesses are run. Today, enterprise data is split into separate databases for performance reasons. Multi-core CPUs, large main memories, cloud computing and powerful mobile devices are serving as the foundation for the transition of enterprises away from this restrictive model. This book provides the technical foundation for processing combined transactional and analytical operations in the same database. In the year since we published the first edition of this book, the performance gains enabled by the use of in-memory technology in enterprise applications has truly marked an inflection point in the market. The new content in this second edition focuses on the development of these in-memory enterprise applications, showing how they leverage the capabilities of in-memory technology. The book is intended for university students, IT-professionals and IT-managers, but also for senior management who wish to create new business processes.

An EPSS is a software context that integrates the support needed to perform a job task--information, software, and expert advice--with the actual job task or tasks. EPSS's provide this support at the appropriate time and in the most appropriate format--ED4 (EPSS Define, Design, Develop, and Deliver). This book describes ED4 and the process that the instructional designers and software engineers used to create the Learning Services Workbench.

As computation continues to move into the cloud, the computing platform of interest no longer resembles a pizza box or a refrigerator, but a warehouse full of computers. These new large datacenters are quite different from traditional hosting facilities of earlier times and cannot be viewed simply as a collection of co-located servers. Large portions of the hardware and software resources in these facilities must work in concert to efficiently deliver good levels of Internet service performance, something that can only be achieved by a holistic approach to their design and deployment. In other words, we must treat the datacenter itself as one massive warehouse-scale computer (WSC). We describe the architecture of WSCs, the main factors influencing their design, operation, and cost structure, and the characteristics of their software base. We hope it will be useful to architects and programmers of today’s WSCs, as well as those of future many-core platforms which may one day implement the equivalent of today’s WSCs on a single board. Notes for the Second Edition After nearly four years of substantial academic and industrial developments in warehouse-scale computing, we are delighted to present our first major update to this lecture. The increased popularity of public clouds has made WSC software techniques relevant to a larger pool of programmers since our first edition. Therefore, we expanded Chapter 2 to reflect our better understanding of WSC software systems and the toolbox of software techniques for WSC programming. In Chapter 3, we added to our coverage of the evolving landscape of wimpy vs. brawny server trade-offs, and we now present an overview of WSC interconnects and storage systems that was promised but lacking in the original edition. Thanks largely to the help of our new co-author, Google Distinguished Engineer Jimmy Clidaras, the material on facility mechanical and power distribution design has been updated and greatly extended (see Chapters 4 and 5). Chapters 6 and 7 have also been revamped significantly. We hope this revised edition continues to meet the needs of educators and professionals in this area.

This volume constitutes the refereed proceedings of the Third International Conference on Geo-Informatics in Resource Management and Sustainable Ecosystem, GRMSE 2015, held in Wuhan, China, in October 2015. The 101 papers presented were carefully reviewed and selected from 321 submissions. The papers are divided into topical sections on Smart City in Resource Management and Sustainable Ecosystem; Spatial Data Acquisition Through RS and GIS in Resource Management and Sustainable Ecosystem; Ecological and Environmental Data Processing and Management; Advanced Geospatial Model and Analysis for Understanding Ecological and Environmental Process; Applications of Geo-Informatics in Resource Management and Sustainable Ecosystem.

'E-business Implementation' is written as a complete guide to successful e-business delivery, from both a project management and a detailed technological perspective. E-business provides a powerful mechanism for organizations to increase productivity and lower costs. However, in order to utilise these considerable benefits, companies must ensure their e-business is implemented correctly and is appropriate to their market segment. 'E-business Implementation' provides a comprehensive guide to successful implementation and is divided into three parts: * Part one begins with a project management structure designed to deliver successful e-business functionality within time and budget, while avoiding the high failure rates common to many technology projects. * Part two details key concepts, technologies, products, vendors, benefits, limitations, and high-level design architectures for e-business, in a phased and risk-managed approach. These include publishing through the Internet and Intranets, portals and content management systems, transacting using e-commerce, integrating internal enterprise applications, integrating with external partners and suppliers, and responding in real-time to changing levels of demand through dynamic e-business and web services. * Part three details a set of critical foundation technologies that must be implemented correctly for the e-business initiative to be successful. These technologies include e-business development languages such as Java, XML and .Net, hardware platforms and their operating systems, security and networking systems, the Internet Domain Name System, and Open Source technologies.