3,072 research outputs found

    Use of linear transverse equalisers and channel state information in combined OFDM-equalisation

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    A high throughput adaptive DFE for HIPERLAN

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    Bootstrap frequency equalisation for MIMO wireless systems

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    An adaptive DFE for high data rate applications

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    Reforming the implementation of European structural funds: A next development step

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    The authors assess the performance of the Structural Funds’ implementation system in six Member States of the European Union. Considering the strengths and weaknesses, they develop a reform model for the implementation of European structural policy after 1999. The strengths of the existing implementation system lie mainly in innovation effects triggered by the Structural Funds' model of policy implementation. Its main weaknesses, inter alia, are an interwoven structure of the decision-making processes, an insufficient time management and a lack of in-built improvement loops in the implementation process. To overcome these shortcomings, the authors propose a strategic management and decentralisation model. It demands a de-coupling of strategic programming on the one hand, and detailed programming and implementation on the other. Under this model, the Commission and the Member State would negotiate on the strategic issues. In the framework of the agreement, the Member State together with the monitoring committees would be responsible for the implementation of the programmes. Strengthened feedback loops would help to assure the attainment of the strategic objectives. -- Die Autoren untersuchen die LeistungsfĂ€higkeit des Implementationssystems der Strukturfondsförderung in sechs Mitgliedstaaten der EuropĂ€ischen Union. Vor dem Hintergrund der StĂ€rken und SchwĂ€chen entwickeln sie ein Reformmodell zur Implementation der Strukturfonds in der nĂ€chsten Förderperiode nach der Reform 1999. Die StĂ€rken des bestehenden Implementationssystems liegen vor allem in den prozeduralen Innovationen, die z.T. auf das Politikmodell der Strukturfonds und seine Kopplung an mitgliedstaatliche Verwaltungsprozesse zurĂŒckgefĂŒhrt werden können. Die wichtigsten SchwĂ€chen sind u.a. die verflochtene Struktur der Entscheidungsprozesse, ein ungenĂŒgendes Zeitmanagement und fehlende inhĂ€rente Verbesserungsmechanismen des Implementationsprozesses. Um diese SchwĂ€chen zu ĂŒberwinden, schlagen die Autoren ein strategisches Management- und Dezentralisierungsmodell vor. Sein Kern besteht in der Trennung von strategischer Programmierung einerseits und Detailprogrammierung und Implementation andererseits. Die EuropĂ€ische Kommission und der jeweilige Mitgliedstaat handeln demnach die strategischen Teile der Programme aus. Im Rahmen dieser strategischen Vereinbarung ist dann der Mitgliedstaat fĂŒr die Detailprogrammierung und Umsetzung der Programme verantwortlich, wobei er vom Begleitausschuß unterstĂŒtzt wird. VerstĂ€rkte Feedbackinstrumente tragen dazu bei, die Einhaltung der strategischen Vorgaben zu sichern.

    Complexity evaluation for the implementation of a pre-FFT equalizer in an OFDM receiver

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    Adaptive equalisation for fading digital communication channels

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    This thesis considers the design of new adaptive equalisers for fading digital communication channels. The role of equalisation is discussed in the context of the functions of a digital radio communication system and both conventional and more recent novel equaliser designs are described. The application of recurrent neural networks to the problem of equalisation is developed from a theoretical study of a single node structure to the design of multinode structures. These neural networks are shown to cancel intersymbol interference in a manner mimicking conventional techniques and simulations demonstrate their sensitivity to symbol estimation errors. In addition the error mechanisms of conventional maximum likelihood equalisers operating on rapidly time-varying channels are investigated and highlight the problems of channel estimation using delayed and often incorrect symbol estimates. The relative sensitivity of Bayesian equalisation techniques to errors in the channel estimate is studied and demonstrates that the structure's equalisation capability is also susceptible to such errors. Applications of multiple channel estimator methods are developed, leading to reduced complexity structures which trade performance for a smaller computational load. These novel structures are shown to provide an improvement over the conventional techniques, especially for rapidly time-varying channels, by reducing the time delay in the channel estimation process. Finally, the use of confidence measures of the equaliser's symbol estimates in order to improve channel estimation is studied and isolates the critical areas in the development of the technique — the production of reliable confidence measures by the equalisers and the statistics of symbol estimation error bursts

    The application of neural networks to communication channel equalisation : a comparison between localised and non-localised basis functions

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    Bibliography: leaves. 63-66.Neural networks have been applied to a number of problems over the past few years. One of the emerging applications of neural networks is adaptive communication channel equalisation. This area of research has become prominent due to the reformulation of the equalisation problem as a classification problem. Viewing equalisation as a classification problem allows researchers to apply the knowledge gained from other fields to equalisation. A wide variety of neural network structures have been suggested to equalise communication channels. Each structure may in turn have a number of different possible algorithms to train the equaliser. A neural network is essentially a non-linear classifier; in general a neural network is able to classify data by employing a non-linear function. The primary subject of this dissertation is the comparative performance of neural networks employing non-localised basis (non-linear) functions (Multi-layer Perceptron) versus those employing localised basis functions (Radial Basis Function Network)
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