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Full-Text Articles in Engineering

Intercarrier Interference Suppression For The Ofdm Systems In Time-Varying Multipath Fading Channels, Xiaozhou Huang Jan 2006

Intercarrier Interference Suppression For The Ofdm Systems In Time-Varying Multipath Fading Channels, Xiaozhou Huang

LSU Doctoral Dissertations

Due to its spectral efficiency and robustness over the multipath channels, orthogonal frequency division multiplexing (OFDM) has served as one of the major modulation schemes for the modern communication systems. In the future, the wireless OFDM systems are expected to operate at high carrier-frequencies, high speed and high throughput mobile reception, where the fasting time-varying fading channels are encountered. The channel variation destroys the orthogonality among the subcarriers and leads to the intercarrier interference (ICI). ICI poses a significant limitation to the wireless OFDM systems. The aim of this dissertation is to find an efficient method of providing reliable communication …


Optical Control Plane: Theory And Algorithms, Stefan Alexandru Pascu Jan 2006

Optical Control Plane: Theory And Algorithms, Stefan Alexandru Pascu

LSU Doctoral Dissertations

In this thesis we propose a novel way to achieve global network information dissemination in which some wavelengths are reserved exclusively for global control information exchange. We study the routing and wavelength assignment problem for the special communication pattern of non-blocking all-to-all broadcast in WDM optical networks. We provide efficient solutions to reduce the number of wavelengths needed for non-blocking all-to-all broadcast, in the absence of wavelength converters, for network information dissemination. We adopt an approach in which we consider all nodes to be tap-and-continue capable thus studying lighttrees rather than lightpaths. To the best of our knowledge, this thesis …


Data-Driven Fault Detection Using Trending Analysis, Min Luo Jan 2006

Data-Driven Fault Detection Using Trending Analysis, Min Luo

LSU Doctoral Dissertations

The objective of this research is to develop data-driven fault detection methods which do not rely on mathematical models yet are capable of detecting process malfunctions. Instead of using mathematical models for comparing performances, the methods developed rely on extensive collection of data to establish classification schemes that detect faults in new data. The research develops two different trending approaches. One uses the normal data to define a one-class classifier. The second approach uses a data mining technique, e.g. support vector machine (SVM) to define multi class classifiers. Each classifier is trained on a set of example objects. The one-class …


Exploring The Hot-Carrier Effect On The Wireless Transceivers, Sameer R. Herlekar Jan 2006

Exploring The Hot-Carrier Effect On The Wireless Transceivers, Sameer R. Herlekar

LSU Doctoral Dissertations

Phase noise can be regarded as the most severe cause of performance degradation in the wireless communication systems. The hot-carriers (HCs), found in the CMOS synchronization circuits, are the high-energy charge carriers that degrade the MOSFET devices’ performance by increasing the threshold voltage required to operate the MOSFETs. The HC effect manifests itself as the phase noise whose level increases with the continued MOSFET operation and such increases result in the performance degradation of the voltage-controlled oscillator (VCO) built on the MOSFETs. The HC effect is particularly evident in the short-channel MOSFET devices. In this dissertation, we analyze the wireless …


Integrated Circuit Metrology By Multilevel Patterning Technology, Li Jiang Jan 2006

Integrated Circuit Metrology By Multilevel Patterning Technology, Li Jiang

LSU Doctoral Dissertations

A low cost, high accuracy method is described in detail for measuring image placement in integrated circuit manufacture. The method measures both the overlay between levels and the absolute placement of features in a single level. The overlay is measured by a technique which views multiple levels separately. The absolute distances between features on a test wafer are measured by comparing the features to precision gratings. Optical imaging techniques are described for viewing and analyzing the grating images, as well as for measuring distortions in the observing microscope and a video camera. These techniques permit image placement measurements to be …


A State-Space Approach To Blind Estimation Of Mimo Wireless Channels, Hesham Mahmoud Zarif Amin Badr Jan 2006

A State-Space Approach To Blind Estimation Of Mimo Wireless Channels, Hesham Mahmoud Zarif Amin Badr

LSU Doctoral Dissertations

This dissertation focuses on blind channel estimation in wireless communications such that the estimated channel admits the minimum phase property. It assumes only the second order statistics of the transmitted signal at the receive side. Our proposed approach is based on the generalized spectral factorization because of the deficient normal rank for the power spectral density (PSD) function of the received signal. We will show the relationship between the generalized spectral factorization and inner-outer factorizations where the inner is square with smaller size. The inner-outer factorization is in turn related to the generalized Kalman filtering in which the dimension of …


Mimo-Ofdm Communication Systems: Channel Estimation And Wireless Location, Zhongshan Wu Jan 2006

Mimo-Ofdm Communication Systems: Channel Estimation And Wireless Location, Zhongshan Wu

LSU Doctoral Dissertations

In this new information age, high data rate and strong reliability features our wireless communication systems and is becoming the dominant factor for a successful deployment of commercial networks. MIMO-OFDM (multiple input multiple output-orthogonal frequency division multiplexing), a new wireless broadband technology, has gained great popularity for its capability of high rate transmission and its robustness against multi-path fading and other channel impairments. A major challenge to MIMO-OFDM systems is how to obtain the channel state information accurately and promptly for coherent detection of information symbols and channel synchronization. In the first part, this dissertation formulates the channel estimation problem …


A Study Of Phase Noise And Jitter In Submicron Cmos Phase-Locked Loop Circuits, Chi Zhang Jan 2006

A Study Of Phase Noise And Jitter In Submicron Cmos Phase-Locked Loop Circuits, Chi Zhang

LSU Doctoral Dissertations

Phase-locked loops (PLLs) are widely used in communication systems. With the continuously expanding of market for high speed, portable communication devices, low noise CMOS submicron integrated circuit designs of PLL for different applications are in large demand. In this dissertation, phase noise and jitter properties of PLL and its building blocks are investigated both at the physical and system levels. At the physical level, hot carrier effect in submicron MOSFETs has been considered. As one of the most dominant noise sources of PLL, the voltage-controlled oscillator (VCO) is considered when investigating the noise degradation induced by the hot carrier effect. …


Compiler Optimization Techniques For Scheduling And Reducing Overhead, Tong-Chai Wang Jan 2006

Compiler Optimization Techniques For Scheduling And Reducing Overhead, Tong-Chai Wang

LSU Doctoral Dissertations

Exploiting parallelism in loops in programs is an important factor in realizing the potential performance of processors today. This dissertation develops and evaluates several compiler optimizations aimed at improving the performance of loops on processors. An important feature of a class of scientific computing problems is the regularity exhibited by their access patterns. Chapter 2 presents an approach of optimizing the address generation of these problems that results in the following: (i) elimination of redundant arithmetic computation by recognizing and exploiting the presence of common sub-expressions across different iterations in stencil codes; and (ii) conversion of as many array references …