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With frequency selective fading, the SNRs of each sub-carrier would vary over the time and frequency. It would then cause fluctuations of the effective SNR. As the decision of MeS in LA is based on the effective SNR, the study of the statistical characterization of effective SNR over frequency selective fading channels would be very important, This problem forms the basis of investigation in this thesis. The methodology used in this thesis is generally divided into two parts. The first part is to investigate the method in obtaining the distribution of EESM over frequency selective fading channels. Such approach will be very helpful for the second part of the work which is to obtain the exact distribution of the EESM effective SNR for a specified fading model. In this case, Nakagami-m fading model is used. The choice of this model is based due to its simplicity and experimental consistency. One of the important features of the distribution is that the SNR of a signal under Nakagami fading is gamma distributed. Thus, in performance evaluation involving Nakagami fading, one can often rely on established results (in the statistics literature) of the gamma distribution. An important special case of the Nakagami distribution is the Rayleigh distribution, which arises in the situation of where the line-of-sight (LOS) component between the transmitter and the receiver is absent, i.e., when all of the received power stems from scattered components. The corresponding distribution for the SNR is the exponential distribution. The research in this thesis represents an effort to provide a statistical characterization of EESM effective SNR which has not appeared in any existing literatures. The goals of this thesis is to Characterize the statistics of EESM effective SNR over frequency selective channels. Obtain the distribution of EESM effective SNR over correlated Nakagami-m fading channels. Theoretically analyze the performance (Le. average SNR, outage probability and Symbol Error Rate (SER) etc.) of EESM over correlated Nakagami-m fading channels. Provide simple approximations to the proposed analytical results. Try to find extension and application of the results.

Liquid chromatography coupled tandem mass spectrometry (LC-MS/MS) has become the preferred method for large-scale peptide and phosphopeptide identification and quantification. The dominance of LC-MS/MS is the result of improved chromatographic, mass spectrometry and bioinformatic technologies. The applications of these technological improvements drive biological innovation by expanding the realm of possible experimentation, facilitating the creation and evaluation of novel hypotheses. Such improvements are the focus of this dissertation. New technologies are presented and their proteome wide applications in biological systems are demonstrated. A comparison of common phosphopeptide enrichment methods is presented in chapter two, which demonstrates that a combination of methods provides non-overlapping data sets. This comparison was performed in mitotically arrested fission yeast, a previously unstudied system by phosphoproteomic methods. This chapter remarks upon phosphorylation site conservation between lower and higher eukaryotes, as a means of predicting potentially relevant phosphorylation events in mammals. A new protocol for tissue based peptide quantification is presented in chapter three. The large-scale application of this method is detailed in a system of mouse liver phosphorylation, between fasted and re-fed states. The effect of peptide and protein level false discovery rates on the accuracy of phosphorylation site quantification is highlighted. This method is a cost-effective alternative to available techniques, such as metabolic labeling, and expands the application of proteomics to include larger animals. Finally, an in depth analysis of quantitative LC-MS/MS based multiplexing is the subject of the last chapter. New techniques for peptide pre-fractionation and ion quantification are discussed, which improve proteome coverage and quantitative accuracy. This proteome-wide multiplexing is applied to an analysis of the budding yeast environmental stress response. Applicable methods of data processing and a means of obtaining biologically relevant information out of multidimensional proteomic data sets are discussed. In all chapters, the data presented represent the largest analyses of their kind. This dissertation provides a solid guide for future proteome-wide studies, focused on the identification and quantification of peptides and their posttranslational modifications.

The initial design of an OFDM transceiver is described and the simulations using MATLAB’s Simulink Software and other FGPA based tools are presented. All components of a modern OFDM system were implemented in Simulink to provide an understanding of the various components of an OFDM system, provide a proof of concept in the design, and measure the theoretical performance of the system. In an effort to build the transceiver, the FFT and randomizer components were implemented in verilog and were successfully simulated using ModelSim Altera Starter Edition 6.5b. A commercially available OFDM core, which did not include forward error correction, was simulated to measure the performance of an OFDM system within Altera Stratix III devices and determine the overall logic utilization for OFDM modulation and demodulation. The goals of this report are to describe in detail the general effort made by the author to build an OFDM transceiver and serve as a driver for its eventual FPGA implementation. / text

The use of feedback to provide channel state information to the transmitter can greatly improve the performance of a communication system. However, the amount of information required to characterize a time-varying MIMO channel can exceed the capacity of the feedback channel. This paper surveys research in limited feedback systems, which employ a number of methods to reduce the information and improve performance in multi-antenna communication systems. This paper also presents a new method, Quantized Successor Pre-coding (QSP), that exploits time-correlation to implement spatial multiplexing in a MIMO system using very little feedback. QSP uses an ordered codebook of pre-coders and transmission modes to reduce the feedback to a single bit. Simulations of QSP demonstrate a substantial performance improvement relative to open-loop spatial multiplexing. / text

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published_or_final_version / abstract / toc / Electrical and Electronic Engineering / Master / Master of Philosophy

published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy

Physical layer security (PLS) is a new paradigm aiming at securing communications between legitimate parties at the physical layer. Conventionally, achieving confidentiality in communication networks relies on cryptographic techniques such as public-key cryptography, secret-key distribution and symmetric encryption. Such techniques are deemed secure based on the assumption of limited computational abilities of a wiretapper. Given the relentless progress in computational capacities and the dynamic topology and proliferation of modern wireless networks, the relevance of the previous techniques in securing communications is more and more questionable and less and less reliable. In contrast to this paradigm, PLS does not assume a specific computational power at any eavesdropper, its premise to guarantee provable security via employing channel coding techniques at the physical layer exploiting the inherent randomness in most communication systems. In this dissertation, we investigate a particular aspect of PLS, which is secret-key agreement, also known as secret-sharing. In this setup, two legitimate parties try to distill a secret-key via the observation of correlated signals through a noisy wireless channel, in the presence of an eavesdropper who must be kept ignorant of the secret-key. Additionally, a noiseless public channel is made available to the legitimate parties to exchange public messages that are also accessible to the eavesdropper. Recall that key agreement is an important aspect toward realizing secure communications in the sense that the key can be used in a one-time pad scheme to send the confidential message. In the first part, our focus is on secret-sharing over Rayleigh fading quasi-static channels. We study the fundamental relationship relating the probability of error and a given target secret-key rate in the high power regime. This is characterized through the diversity multiplexing tradeoff (DMT) concept, that we define for our model and then characterize it. We show that the impact of the secrecy constraint is to reduce the effective number of transmit antennas by the number of antennas at the eavesdropper. Toward this characterization, we provide several schemes achieving the DMT and we highlight disparities between coding for the wiretap channel and coding for secret-key agreement. In the second part of the present work, we consider a fast-fading setting in which the wireless channels change during each channel use. We consider a correlated environment where transmit, legitimate receiver and eavesdropper antennas are correlated. We characterize the optimal strategy achieving the highest secret-key rate. We also identify the impact of correlation matrices and illustrate our analysis with various numerical results. Finally, we study the system from an energy-efficiency point of view and evaluate relevant metrics as the minimum energy required for sharing a secret-key bit and the wideband slope.

No description available.