+publisher:"University of Colorado" +contributor:("Youjian")

University of Colorado

1. Tembarai Krishnamachari, Rajesh. A Geometric Framework for Analyzing the Performance of Multiple-Antenna Systems under Finite-Rate Feedback.

Degree: PhD, Electrical, Computer & Energy Engineering, 2011, University of Colorado

URL: https://scholar.colorado.edu/ecen_gradetds/38

► We study the performance of multiple-antenna systems under finite-rate feedback of some function of the current channel realization from a channel-aware receiver to the… (more)

▼ We study the performance of multiple-antenna systems under finite-rate feedback of some function of the current channel realization from a channel-aware receiver to the transmitter. Our analysis is based on a novel geometric paradigm whereby the feedback information is modeled as a source distributed over a Riemannian manifold. While the right singular vectors of the channel matrix and the subspace spanned by them are located on the traditional Stiefel and Grassmann surfaces, the optimal input covariance matrix is located on a new manifold of positive semi-definite matrices - specified by rank and trace constraints - called the Pn manifold. The geometry of these three manifolds is studied in detail; in particular, the precise series expansion for the volume of geodesic balls over the Grassmann and Stiefel manifolds is obtained. Using these geometric results, the distortion incurred in quantizing sources using either a sphere-packing or a random code over an arbitrary manifold is quantified. Perturbative expansions are used to evaluate the susceptibility of the ergodic information rate to the quality of feedback information, and thereby to obtain the tradeoff of the achievable rate with the number of feedback bits employed. For a given system strategy, the gap between the achievable rates in the infinite and finite-rate feedback cases is shown to be O(2^-\frac{2N_f{N}}) for Grassmann feedback and O(2^-\frac{N_f{N}}) for other cases, where N is the dimension of the manifold used for quantization and N_f is the number of bits used by the receiver per block for feedback. The geometric framework developed enables the results to hold for arbitrary distributions of the channel matrix and extends to all covariance computation strategies including, waterfilling in the short-term/long-term power constraint case, antenna selection and other rank-limited scenarios that could not be analyzed using previous probabilistic approaches. Advisors/Committee Members: Mahesh K. Varanasi, Youjian(Eugene) Liu, Shannon M. Hughes.

Subjects/Keywords: Finite-rate Feedback; Grassmann/Stiefel Manifold; Information Theory; MIMO; Riemannian Geometry; Wireless Communications; Electrical and Computer Engineering; Mathematics

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APA (6^th Edition):

Tembarai Krishnamachari, R. (2011). A Geometric Framework for Analyzing the Performance of Multiple-Antenna Systems under Finite-Rate Feedback. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/ecen_gradetds/38

Chicago Manual of Style (16^th Edition):

Tembarai Krishnamachari, Rajesh. “A Geometric Framework for Analyzing the Performance of Multiple-Antenna Systems under Finite-Rate Feedback.” 2011. Doctoral Dissertation, University of Colorado. Accessed January 23, 2021. https://scholar.colorado.edu/ecen_gradetds/38.

MLA Handbook (7^th Edition):

Tembarai Krishnamachari, Rajesh. “A Geometric Framework for Analyzing the Performance of Multiple-Antenna Systems under Finite-Rate Feedback.” 2011. Web. 23 Jan 2021.

Vancouver:

Tembarai Krishnamachari R. A Geometric Framework for Analyzing the Performance of Multiple-Antenna Systems under Finite-Rate Feedback. [Internet] [Doctoral dissertation]. University of Colorado; 2011. [cited 2021 Jan 23]. Available from: https://scholar.colorado.edu/ecen_gradetds/38.

Council of Science Editors:

Tembarai Krishnamachari R. A Geometric Framework for Analyzing the Performance of Multiple-Antenna Systems under Finite-Rate Feedback. [Doctoral Dissertation]. University of Colorado; 2011. Available from: https://scholar.colorado.edu/ecen_gradetds/38

University of Colorado

2. Bailey, Robert Alan. Trajectory Exploration and Maneuver Regulation of the Pendubot.

Degree: PhD, Electrical, Computer & Energy Engineering, 2012, University of Colorado

URL: https://scholar.colorado.edu/ecen_gradetds/40

► The pendulum provides a seemingly inexhaustible source of practical applications and interesting problems which have motivated research in a variety of disciplines. In this… (more)

▼ The pendulum provides a seemingly inexhaustible source of practical applications and interesting problems which have motivated research in a variety of disciplines. In this thesis, we study equations that described a driven pendulum with odd-periodic driving. The equations also describe the under-actuated, double pendulum system called the pendubot. Techniques for trajectory exploration are developed. For the inverted pendulum, we first wrote the problem as a two point boundary value problem with Dirichlet boundary conditions. Then, we develop an equivalent linear operator that combines a Nemitski operator (or superposition operator) with the linear operator for the unstable harmonic oscillator. By exploring the properties of the Green’s function for the unstable harmonic oscillator with Dirichlet boundary conditions, we developed bounds on various norms that prove useful for determining which parameter values will satisfy invariance and contraction conditions. With a direct application of the Schauder fixed point theorem, we showed that our family of equations representing an inverted pendulum always possessed an odd-periodic solution. Using the Banach fixed point theorem we showed that there is a unique solution within an invariant region of the space of possible solution curves. When there is a unique solution, successive approximations can be used to compute the solution trajectory. To illustrate the power and application of these ideas, we apply them to a pendubot with the inner arm moving at a constant velocity. For non-inverted trajectories of the pendubot, we presented a necessary condition for trajectories to exist with general periodic forcing. For odd-periodic periodic driving functions this condition is always satisfied. For a driving function of A sin(wt), we found multiple solutions for the outer link. With the trajectories in hand, we demonstrated through simulation and/or physical implementation, the usefulness of maneuver regulation for providing orbital stabilization. Advisors/Committee Members: John Hauser, Youjian (Eugene) Liu, Jason Marden.

Subjects/Keywords: Control Theory; Differential Equations; Inverted Pendulum; Maneuver Regulation; Pendubot; Pendulum; Controls and Control Theory; Electrical and Computer Engineering

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APA (6^th Edition):

Bailey, R. A. (2012). Trajectory Exploration and Maneuver Regulation of the Pendubot. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/ecen_gradetds/40

Chicago Manual of Style (16^th Edition):

Bailey, Robert Alan. “Trajectory Exploration and Maneuver Regulation of the Pendubot.” 2012. Doctoral Dissertation, University of Colorado. Accessed January 23, 2021. https://scholar.colorado.edu/ecen_gradetds/40.

MLA Handbook (7^th Edition):

Bailey, Robert Alan. “Trajectory Exploration and Maneuver Regulation of the Pendubot.” 2012. Web. 23 Jan 2021.

Vancouver:

Bailey RA. Trajectory Exploration and Maneuver Regulation of the Pendubot. [Internet] [Doctoral dissertation]. University of Colorado; 2012. [cited 2021 Jan 23]. Available from: https://scholar.colorado.edu/ecen_gradetds/40.

Council of Science Editors:

Bailey RA. Trajectory Exploration and Maneuver Regulation of the Pendubot. [Doctoral Dissertation]. University of Colorado; 2012. Available from: https://scholar.colorado.edu/ecen_gradetds/40

University of Colorado

3. Anitha, Anila. Underpainting Recovery using Synchrotron-based X-ray Fluorescence Imaging Data.

Degree: MS, Electrical, Computer & Energy Engineering, 2010, University of Colorado

URL: https://scholar.colorado.edu/ecen_gradetds/15

► Virtual restoration of underpaintings, paintings that have been painted over, has become realizable with data from non-invasive X-ray imaging techniques. With the advent of… (more)

Subjects/Keywords: art restoration; attenuating hue; color estimation; computerized analysis of art; source separation; underpainting recovery; Electrical and Computer Engineering; Fine Arts

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APA (6^th Edition):

Anitha, A. (2010). Underpainting Recovery using Synchrotron-based X-ray Fluorescence Imaging Data. (Masters Thesis). University of Colorado. Retrieved from https://scholar.colorado.edu/ecen_gradetds/15

Chicago Manual of Style (16^th Edition):

Anitha, Anila. “Underpainting Recovery using Synchrotron-based X-ray Fluorescence Imaging Data.” 2010. Masters Thesis, University of Colorado. Accessed January 23, 2021. https://scholar.colorado.edu/ecen_gradetds/15.

MLA Handbook (7^th Edition):

Anitha, Anila. “Underpainting Recovery using Synchrotron-based X-ray Fluorescence Imaging Data.” 2010. Web. 23 Jan 2021.

Vancouver:

Anitha A. Underpainting Recovery using Synchrotron-based X-ray Fluorescence Imaging Data. [Internet] [Masters thesis]. University of Colorado; 2010. [cited 2021 Jan 23]. Available from: https://scholar.colorado.edu/ecen_gradetds/15.

Council of Science Editors:

Anitha A. Underpainting Recovery using Synchrotron-based X-ray Fluorescence Imaging Data. [Masters Thesis]. University of Colorado; 2010. Available from: https://scholar.colorado.edu/ecen_gradetds/15

University of Colorado

4. Mysore Balasubramanya, Naveen. Interference Time Analysis for a Cognitive Radio on an Unmanned Aircraft.

Degree: MS, Electrical, Computer & Energy Engineering, 2010, University of Colorado

URL: https://scholar.colorado.edu/ecen_gradetds/14

► This thesis considers a model consisting of a cognitive radio (CR) on an unmanned aircraft (UA) and a network of licensed primary users on… (more)

▼ This thesis considers a model consisting of a cognitive radio (CR) on an unmanned aircraft (UA) and a network of licensed primary users on the ground. The cognitive radio uses the same frequency spectrum as the primary users for its operation and hence acts as an interferer. This work analyzes the duration of interference in such a model. It defines two important metrics – the interference radius and the detection radius. The interference radius determines the boundary of the area within which a primary user might be subjected to harmful interference due to the operation of the CR. The detection radius determines the boundary of the area within which the presence of a primary user might be detected by the CR. The interference and detection radii might vary due to the dynamic nature of the radio environment. This thesis derives the dependence of these metrics on the radio propagation parameters like antenna gain, antenna height, path-loss exponents, etc. It uses these metrics and characterizes the model using an M/G/infinity queue to determine the statistics of the interference time for the entire excursion of the unmanned aircraft. The key statistics determined are the distribution of the duration of interference periods, the mean and the total interference time. Firstly, this work analyzes a 1D system model where the primary users are distributed randomly along a straight line. The results are then extended to a 2D system where the primary users are distributed randomly over an area. The analysis is carried out for both sparsely-dense and highly-dense primary user ground network. This work gives a new dimension to analyze the effects of interference in terms of duration of interference. It also shows how these interference effects can be minimized on enhancing the detection capability of the cognitive radio. The results from this work can be used to determine the optimum setting for the cognitive radio system such that it restrains the duration of interference below tolerable limits. Advisors/Committee Members: Timothy X Brown, Youjian (Eujene) Liu, Juan Restrepo.

Subjects/Keywords: cognitive radio; detection capability; duration of interference; interference analysis; M/G/infinity queue; unmanned aircraft; Aviation; Electrical and Computer Engineering

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APA (6^th Edition):

Mysore Balasubramanya, N. (2010). Interference Time Analysis for a Cognitive Radio on an Unmanned Aircraft. (Masters Thesis). University of Colorado. Retrieved from https://scholar.colorado.edu/ecen_gradetds/14

Chicago Manual of Style (16^th Edition):

Mysore Balasubramanya, Naveen. “Interference Time Analysis for a Cognitive Radio on an Unmanned Aircraft.” 2010. Masters Thesis, University of Colorado. Accessed January 23, 2021. https://scholar.colorado.edu/ecen_gradetds/14.

MLA Handbook (7^th Edition):

Mysore Balasubramanya, Naveen. “Interference Time Analysis for a Cognitive Radio on an Unmanned Aircraft.” 2010. Web. 23 Jan 2021.

Vancouver:

Mysore Balasubramanya N. Interference Time Analysis for a Cognitive Radio on an Unmanned Aircraft. [Internet] [Masters thesis]. University of Colorado; 2010. [cited 2021 Jan 23]. Available from: https://scholar.colorado.edu/ecen_gradetds/14.

Council of Science Editors:

Mysore Balasubramanya N. Interference Time Analysis for a Cognitive Radio on an Unmanned Aircraft. [Masters Thesis]. University of Colorado; 2010. Available from: https://scholar.colorado.edu/ecen_gradetds/14

University of Colorado

5. Karmakar, Sanjay. Information Theoretic Limits of MIMO Interference and Relay Networks.

Degree: PhD, Electrical, Computer & Energy Engineering, 2012, University of Colorado

URL: https://scholar.colorado.edu/ecen_gradetds/43

► In this thesis, the information theoretic performance limits of two important building blocks of the general multi-user wireless network, namely, the interference channel… (more)

▼ In this thesis, the information theoretic performance limits of two important building blocks of the general multi-user wireless network, namely, the interference channel and the relay channel, are characterized. We consider both time-invariant and time-varying or fading channel. In the first part, we focus on the 2-user interference channel with time-invariant channel coefficients. First, we characterize the capacity region of a class of MIMO IC called strong in partial order ICs. It turns out that for this class of channels decoding both the messages at both the receivers is optimal, i.e., the capacity region is identical to that of the compound multiple access channel (MAC). The defining constraints on the channel coefficients for the class of strong in partial order ICs enable us to derive a novel tight upper bound to the sum rate of the channel – a problem that is very difficult for general channel coefficients. To avoid this difficulty for the general IC, we next derive upper and lower bounds which are not identical but are within a constant number of bits to each other which characterizes the capacity region of the 2-user multi-input multi-output (MIMO) Gaussian interference channel (IC) with an arbitrary number of antennas at each node to within a constant gap that is independent of the signal-to-noise ratio (SNR) and all channel parameters. In contrast to an earlier result in [Telatar and Tse, ISIT, 2007], where both the achievable rate region and upper bounds to the capacity region of a general class of interference channels was specified as the union over all possible input distributions here we provide, a simple and an explicit achievable coding scheme for the achievable region and an explicit outer bound. We also illustrate an interesting connection of the simple achievable coding scheme to MMSE estimators at the receivers. A reciprocity result is also proved which is that the capacity of the reciprocal MIMO IC is within a constant gap of the capacity region of the forward MIMO IC. We also analyze the channel's performance in the high SNR regime, which is obtained from the explicit expressions of the approximate capacity region and the resulting asymptotic rate region is known as the generalized degrees of freedom (GDoF) region. A close examination of the super position coding scheme which is both GDoF and approximate capacity optimal reveals that joint signal-space and signal-level interference alignment is necessary to achieve the GDoF region of the channel. The admissible DoF-splits between the private and common messages of the HK scheme are also specified. A study of the GDoF region reveals various insights through the joint dependence of optimal interference management techniques (at high SNR) on the SNR exponents and the numbers of antennas at the four terminals. For instance, it reveals that, unlike in the scalar IC, treating interference as noise is not always GDoF-optimal even in the very weak interference regime. Moreover, while the DoF-optimal… Advisors/Committee Members: Mahesh K. Varanasi, Youjian Liu, Brian C. Rider.

Subjects/Keywords: Capacity MIMO interference channel; Diversity multiplexing tradeoff of MIMO relay channel; DMT of MIMO IC; ZIC; Generalized degrees of freedom of MIMO IC; MIMO cooperative networks; MIMO strong IC; GDoF; Electrical and Computer Engineering

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APA (6^th Edition):

Karmakar, S. (2012). Information Theoretic Limits of MIMO Interference and Relay Networks. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/ecen_gradetds/43

Chicago Manual of Style (16^th Edition):

Karmakar, Sanjay. “Information Theoretic Limits of MIMO Interference and Relay Networks.” 2012. Doctoral Dissertation, University of Colorado. Accessed January 23, 2021. https://scholar.colorado.edu/ecen_gradetds/43.

MLA Handbook (7^th Edition):

Karmakar, Sanjay. “Information Theoretic Limits of MIMO Interference and Relay Networks.” 2012. Web. 23 Jan 2021.

Vancouver:

Karmakar S. Information Theoretic Limits of MIMO Interference and Relay Networks. [Internet] [Doctoral dissertation]. University of Colorado; 2012. [cited 2021 Jan 23]. Available from: https://scholar.colorado.edu/ecen_gradetds/43.

Council of Science Editors:

Karmakar S. Information Theoretic Limits of MIMO Interference and Relay Networks. [Doctoral Dissertation]. University of Colorado; 2012. Available from: https://scholar.colorado.edu/ecen_gradetds/43

University of Colorado

6. Chong, Joshua Wei Kuang. Manifold-Based System for Passive-Active Spectrum Sharing.

Degree: MS, Electrical, Computer & Energy Engineering, 2014, University of Colorado

URL: https://scholar.colorado.edu/ecen_gradetds/1

► A feasibility study for an automated scheme for spectrum sharing between passive and active users is presented. The needs of spectrum users can be… (more)

▼ A feasibility study for an automated scheme for spectrum sharing between passive and active users is presented. The needs of spectrum users can be represented by manifolds in a Euclidean hyperspace called electrospace which has 7 dimensions: frequency (f); Cartesian coordinates (x,y,z); angular coordinates (θ,ø), and time (t). The entire globe is tessellated into geographical areas containing spectrum users, called user domains. Each user domain is recursively tessellated into smaller user domains, or subdomains. A computer cluster, or broker, in each smallest subdomain performs the calculations necessary to determine if a particular user in the subdomain experiences interference. Throughout this thesis, the Chicago Loop (area of 4.09 km², population ~ 21, 000) is taken to be the representative example of a smallest subdomain. Within each subdomain, the number of users served by a broker is reduced to a manageable number by the process of culling. There are three orders of culling. In first-order culling, subdomain pairs without line of sight and not close enough to mutually interfere are culled, or removed from further consideration for interference calculations. In second-order culling, within each subdomain an intersection test of the electrospace manifolds of all user pairs is performed. User pairs whose manifolds do not intersect are culled. In third-order culling a Friis calculation is performed for all remaining user pairs. The output of third-order culling is an RFI flag bit for each user indicating whether interference is present or not. The computational complexity of first-, second-, and third-order culling calculations was determined. Three representative user classes will be discussed: WiFi access points, Terminal Doppler Weather Radars, and passive EESS satellites. The manifold descriptor language (MDL) for each of the three user classes was described. The computational complexity of broker calculations to determine electrospace parameters from the MDL was determined. Using this complexity and the complexity of culling calculations, the total computational requirements for a broker in a representative subdomain is determined in GFLOPS (Giga Floating Point Operations Per Second). Advisors/Committee Members: Albin J. Gasiewski, Dirk Grunwald, Youjian Liu.

Subjects/Keywords: Manifolds; Radio frequency interference; Spectrum sharing; Computer Sciences; Electrical and Computer Engineering

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APA (6^th Edition):

Chong, J. W. K. (2014). Manifold-Based System for Passive-Active Spectrum Sharing. (Masters Thesis). University of Colorado. Retrieved from https://scholar.colorado.edu/ecen_gradetds/1

Chicago Manual of Style (16^th Edition):

Chong, Joshua Wei Kuang. “Manifold-Based System for Passive-Active Spectrum Sharing.” 2014. Masters Thesis, University of Colorado. Accessed January 23, 2021. https://scholar.colorado.edu/ecen_gradetds/1.

MLA Handbook (7^th Edition):

Chong, Joshua Wei Kuang. “Manifold-Based System for Passive-Active Spectrum Sharing.” 2014. Web. 23 Jan 2021.

Vancouver:

Chong JWK. Manifold-Based System for Passive-Active Spectrum Sharing. [Internet] [Masters thesis]. University of Colorado; 2014. [cited 2021 Jan 23]. Available from: https://scholar.colorado.edu/ecen_gradetds/1.

Council of Science Editors:

Chong JWK. Manifold-Based System for Passive-Active Spectrum Sharing. [Masters Thesis]. University of Colorado; 2014. Available from: https://scholar.colorado.edu/ecen_gradetds/1

University of Colorado

7. Kambli, Ketan Pradeep. Manifold Learning for Organization of Text Documents.

Degree: MS, Electrical, Computer & Energy Engineering, 2011, University of Colorado

URL: https://scholar.colorado.edu/eeng_gradetds/18

► The quantity of information in the world is soaring. We are living in an information age with abundant sources that generate information. While this… (more)

▼ The quantity of information in the world is soaring. We are living in an information age with abundant sources that generate information. While this data has the potential to transform every aspect of our life, it is very difficult to analyze and make inference from this huge amount of data. One example of this data deluge is the massive amount of textual data being generated on a daily basis from sources such as newspapers, blogs, tweets and other social network posts, emails, research papers, product descriptions and reviews, online discussion forums, digital libraries, knowledge databases, etc. This thesis tackles the problem of finding the hidden structure behind these collections of text documents and of organizing them better so as to help better navigate this sea of textual data. Traditionally, the techniques used to classify the documents by topic include probabilistic methods such as the naive Bayes classifier, margin-based learning techniques such as support vector machines, and statistical manifold learning methods such as the Fisher information non-parametric embedding. We believe that the set of documents can be represented by points in a high-dimensional space that lie on or near a low-dimensional manifold. Hence, manifold learning or dimensionality reduction techniques can help to recover the underlying manifold and retrieve the inherent modes of variability in the set of documents. This will aid towards effective organization of these documents. Indeed, we find that many popular manifold learning methods perform well at organizing test datasets. We also propose a different view of the local similarity of documents and thereby introduce the Earth Mover's distance as a local distance metric to replace Euclidean distance metric for the distance between the documents. The manifold learning methods, modified to incorporate the Earth Mover's distance, do provide improvement in the results as expected. Finally, we show that the spectral clustering promises to be a useful technique for the purpose of text organization. Advisors/Committee Members: Shannon M. Hughes, Peter Mathys, Youjian Liu.

Subjects/Keywords: dimensionality reduction; earth mover's distance; manifold learning; text organization; textual data deluge; Artificial Intelligence and Robotics; Computer Sciences; Electrical and Computer Engineering

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APA (6^th Edition):

Kambli, K. P. (2011). Manifold Learning for Organization of Text Documents. (Masters Thesis). University of Colorado. Retrieved from https://scholar.colorado.edu/eeng_gradetds/18

Chicago Manual of Style (16^th Edition):

Kambli, Ketan Pradeep. “Manifold Learning for Organization of Text Documents.” 2011. Masters Thesis, University of Colorado. Accessed January 23, 2021. https://scholar.colorado.edu/eeng_gradetds/18.

MLA Handbook (7^th Edition):

Kambli, Ketan Pradeep. “Manifold Learning for Organization of Text Documents.” 2011. Web. 23 Jan 2021.

Vancouver:

Kambli KP. Manifold Learning for Organization of Text Documents. [Internet] [Masters thesis]. University of Colorado; 2011. [cited 2021 Jan 23]. Available from: https://scholar.colorado.edu/eeng_gradetds/18.

Council of Science Editors:

Kambli KP. Manifold Learning for Organization of Text Documents. [Masters Thesis]. University of Colorado; 2011. Available from: https://scholar.colorado.edu/eeng_gradetds/18

University of Colorado

8. Bennett, Daniel T. Optimal Data Scheduling of Clients Serviced using Beamforming Antennas in Mobile Scenarios.

Degree: PhD, Electrical, Computer & Energy Engineering, 2012, University of Colorado

URL: https://scholar.colorado.edu/ecen_gradetds/47

► The use of beamforming antennas has received significant attention over the last decade. I consider beamforming applied to dynamic operations such as networked UAV… (more)

Subjects/Keywords: Beamforming Antennas; UAV Communications; Wireless Communications; Communication Technology and New Media; Computer Engineering

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APA (6^th Edition):

Bennett, D. T. (2012). Optimal Data Scheduling of Clients Serviced using Beamforming Antennas in Mobile Scenarios. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/ecen_gradetds/47

Chicago Manual of Style (16^th Edition):

Bennett, Daniel T. “Optimal Data Scheduling of Clients Serviced using Beamforming Antennas in Mobile Scenarios.” 2012. Doctoral Dissertation, University of Colorado. Accessed January 23, 2021. https://scholar.colorado.edu/ecen_gradetds/47.

MLA Handbook (7^th Edition):

Bennett, Daniel T. “Optimal Data Scheduling of Clients Serviced using Beamforming Antennas in Mobile Scenarios.” 2012. Web. 23 Jan 2021.

Vancouver:

Bennett DT. Optimal Data Scheduling of Clients Serviced using Beamforming Antennas in Mobile Scenarios. [Internet] [Doctoral dissertation]. University of Colorado; 2012. [cited 2021 Jan 23]. Available from: https://scholar.colorado.edu/ecen_gradetds/47.

Council of Science Editors:

Bennett DT. Optimal Data Scheduling of Clients Serviced using Beamforming Antennas in Mobile Scenarios. [Doctoral Dissertation]. University of Colorado; 2012. Available from: https://scholar.colorado.edu/ecen_gradetds/47

University of Colorado

9. Qi, Hanchao. Low-Dimensional Signal Models in Compressive Sensing.

Degree: PhD, Electrical, Computer & Energy Engineering, 2013, University of Colorado

URL: https://scholar.colorado.edu/ecen_gradetds/68

► In today's world, we often face an explosion of data that can be difficult to handle. Signal models help make this data tractable, and… (more)

▼ In today's world, we often face an explosion of data that can be difficult to handle. Signal models help make this data tractable, and thus play an important role in designing efficient algorithms for acquiring, storing, and analyzing signals. However, choosing the right model is critical. Poorly chosen models may fail to capture the underlying structure of signals, making it hard to achieve satisfactory results in signal processing tasks. Thus, the most accurate and concise signal models must be used. Many signals can be expressed as a linear combination of a few elements of some dictionary, and this is the motivation behind the emerging field of compressive sensing. Compressive sensing leverages this signal model to enable us to perform signal processing tasks without full knowledge of the data. However, this is only one possible model for signals, and many signals could in fact be more accurately and concisely described by other models. In particular, in this thesis, we will look at two such models, and show how these other two models can be used to allow signal reconstruction and analysis from partial knowledge of the data. First, we consider signals that belong to low-dimensional nonlinear manifolds, i.e. that can be represented as a continuous nonlinear function of few parameters. We show how to apply the kernel trick, popular in machine learning, to adapt compressive sensing to this type of sparsity. Our approach provides computationally-efficient, improved signal reconstruction from partial measurements when the signal is accurately described by such a manifold model. We then consider collections of signals that together have strong principal components, so that each individual signal may be modeled as a linear combination of these few shared principal components. We focus on the problem of finding the center and principal components of these high-dimensional signals using only their measurements. We show experimentally and theoretically that our approach will generally return the correct center and principal components for a large enough collection of signals. The recovered principal components also allow performance gains in other signal processing tasks. Advisors/Committee Members: Shannon M. Hughes, Youjian Liu, Francois Meyer, Lijun Chen, Alireza Doostan.

Subjects/Keywords: algorithms; compressive sensing; nonlinear manifolds; high-dimensional signals; Electrical and Computer Engineering

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APA (6^th Edition):

Qi, H. (2013). Low-Dimensional Signal Models in Compressive Sensing. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/ecen_gradetds/68

Chicago Manual of Style (16^th Edition):

Qi, Hanchao. “Low-Dimensional Signal Models in Compressive Sensing.” 2013. Doctoral Dissertation, University of Colorado. Accessed January 23, 2021. https://scholar.colorado.edu/ecen_gradetds/68.

MLA Handbook (7^th Edition):

Qi, Hanchao. “Low-Dimensional Signal Models in Compressive Sensing.” 2013. Web. 23 Jan 2021.

Vancouver:

Qi H. Low-Dimensional Signal Models in Compressive Sensing. [Internet] [Doctoral dissertation]. University of Colorado; 2013. [cited 2021 Jan 23]. Available from: https://scholar.colorado.edu/ecen_gradetds/68.

Council of Science Editors:

Qi H. Low-Dimensional Signal Models in Compressive Sensing. [Doctoral Dissertation]. University of Colorado; 2013. Available from: https://scholar.colorado.edu/ecen_gradetds/68

University of Colorado

10. Pourkamali Anaraki, Farhad. Randomized Algorithms for Large-Scale Data Analysis.

Degree: PhD, 2017, University of Colorado

URL: https://scholar.colorado.edu/ecen_gradetds/141

► Massive high-dimensional data sets are ubiquitous in all scientific disciplines. Extracting meaningful information from these data sets will bring future advances in fields of… (more)

▼ Massive high-dimensional data sets are ubiquitous in all scientific disciplines. Extracting meaningful information from these data sets will bring future advances in fields of science and engineering. However, the complexity and high-dimensionality of modern data sets pose unique computational and statistical challenges. The computational requirements of analyzing large-scale data exceed the capacity of traditional data analytic tools. The challenges surrounding large high-dimensional data are felt not just in processing power, but also in memory access, storage requirements, and communication costs. For example, modern data sets are often too large to fit into the main memory of a single workstation and thus data points are processed sequentially without a chance to store the full data. Therefore, there is an urgent need for the development of scalable learning tools and efficient optimization algorithms in today's high-dimensional data regimes. A powerful approach to tackle these challenges is centered around preprocessing high-dimensional data sets via a dimensionality reduction technique that preserves the underlying geometry and structure of the data. This approach stems from the observation that high-dimensional data sets often have intrinsic dimension which is significantly smaller than the ambient dimension. Therefore, information-preserving dimensionality reduction methods are valuable tools for reducing the memory and computational requirements of data analytic tasks on large-scale data sets. Recently, randomized dimension reduction has received a lot of attention in several fields, including signal processing, machine learning, and numerical linear algebra. These methods use random sampling or random projection to construct low-dimensional representations of the data, known as sketches or compressive measurements. These randomized methods are effective in modern data settings since they provide a non-adaptive data-independent mapping of high-dimensional data into a low-dimensional space. However, such methods require strong theoretical guarantees to ensure that the key properties of original data are preserved under a randomized mapping. This dissertation focuses on the design and analysis of efficient data analytic tasks using randomized dimensionality reduction techniques. Specifically, four efficient signal processing and machine learning algorithms for large high-dimensional data sets are proposed: covariance estimation and principal component analysis, dictionary learning, clustering, and low-rank approximation of positive semidefinite kernel matrices. These techniques are valuable tools to extract important information and patterns from massive data sets. Moreover, an efficient data sparsification framework is introduced that does not require incoherence and distributional assumptions on the data. A main feature of the proposed compression scheme is that it requires only one pass over the data due to the randomized preconditioning transformation, which makes it applicable to… Advisors/Committee Members: Stephen Becker, Michael B. Wakin, Youjian Liu, Xudong Chen, Alireza Doostan.

Subjects/Keywords: massive data sets; data storage; high-dimensional data sets; Applied Mathematics; Computer Sciences; Electrical and Computer Engineering

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APA (6^th Edition):

Pourkamali Anaraki, F. (2017). Randomized Algorithms for Large-Scale Data Analysis. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/ecen_gradetds/141

Chicago Manual of Style (16^th Edition):

Pourkamali Anaraki, Farhad. “Randomized Algorithms for Large-Scale Data Analysis.” 2017. Doctoral Dissertation, University of Colorado. Accessed January 23, 2021. https://scholar.colorado.edu/ecen_gradetds/141.

MLA Handbook (7^th Edition):

Pourkamali Anaraki, Farhad. “Randomized Algorithms for Large-Scale Data Analysis.” 2017. Web. 23 Jan 2021.

Vancouver:

Pourkamali Anaraki F. Randomized Algorithms for Large-Scale Data Analysis. [Internet] [Doctoral dissertation]. University of Colorado; 2017. [cited 2021 Jan 23]. Available from: https://scholar.colorado.edu/ecen_gradetds/141.

Council of Science Editors:

Pourkamali Anaraki F. Randomized Algorithms for Large-Scale Data Analysis. [Doctoral Dissertation]. University of Colorado; 2017. Available from: https://scholar.colorado.edu/ecen_gradetds/141

University of Colorado

11. Vaze, Chinmay Shankar. Degrees of Freedom of Single-hop and Multi-hop MIMO Interference Networks with Feedback and Cooperation.

Degree: PhD, Electrical, Computer & Energy Engineering, 2012, University of Colorado

URL: https://scholar.colorado.edu/ecen_gradetds/49

► A multiple-input multiple-output (MIMO) communication network consists of a set of multi-antenna transmitters and receivers that communicate over a common noisy medium. Each transmitter… (more)

▼ A multiple-input multiple-output (MIMO) communication network consists of a set of multi-antenna transmitters and receivers that communicate over a common noisy medium. Each transmitter has access to a set of messages, each of which it needs to deliver to one of the receivers. Since the transmitter(s) transmit multiple messages over such networks, each receiver encounters interference due to undesired transmissions. This interference seen by the receivers is, in fact, the main factor that limits the capacity regions of such networks. Hence, to attain high data-rates, efficient interference management is crucial, and for the same reason, these networks are also known as interference networks. A common and by far the most important MIMO interference network is a wireless cellular network. A wireless signal after its transmission undergoes attenuation or fading. The set of all channel fading coefficients between different pairs of transmit-receive antennas is called the channel state. If this channel state is known to all terminals of the network, sophisticated interference management schemes can be implemented to achieve high data-rates. While, in practice, channel state information (CSI) can be obtained at the receivers via pilot transmissions, there is no natural way for acquiring CSI at transmitters (CSIT). Unfortunately, the lack of CSIT severely affects the capacity regions of almost all MIMO networks. To avoid this capacity loss, the next-generation cellular standards are making a provision for having feedback links from the receivers to the transmitters over which the latter can be informed about the channel state. However, due to the dynamic nature of the wireless environment, the channel state is time-varying, which makes it difficult for the transmitters to obtain feedback in a timely manner. Specifically, by the time feedback is available to the transmitters, the channel state may have already changed to a significantly different value. This motivates the study of MIMO interference networks with strictly delayed feedback, which is the main topic of this thesis. We analyze various feedback models depending upon whether the channel state or the channel outputs (i.e., the received signals) or both or a function of the two is fed back. We further consider the worst-case scenario, where the channel state changes independently across time and feedback is available with some delay. Under such a setting, feedback is rather outdated because the information obtained via feedback is completely irrelevant as far as the current channel state is concerned. It may seem here that outdated feedback can not be of much use, which is indeed true for the simplest MIMO network with a single transmitter-receiver pair. Surprisingly, we prove here for the MIMO broadcast channel (BC, a one-to-two, generally, one-to-many system) and for the MIMO interference channel (IC, a system with two transmit-receive pairs) that outdated feedback can significantly improve their capacity regions, relative to the… Advisors/Committee Members: Mahesh K. Varanasi, Youjian Liu, Shannon Hughes, Peter Mathys, Brian Rider.

Subjects/Keywords: cooperation; degrees of freedom; feedback; information theory; interference alignment; wireless communication networks; Electrical and Computer Engineering

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APA (6^th Edition):

Vaze, C. S. (2012). Degrees of Freedom of Single-hop and Multi-hop MIMO Interference Networks with Feedback and Cooperation. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/ecen_gradetds/49

Chicago Manual of Style (16^th Edition):

Vaze, Chinmay Shankar. “Degrees of Freedom of Single-hop and Multi-hop MIMO Interference Networks with Feedback and Cooperation.” 2012. Doctoral Dissertation, University of Colorado. Accessed January 23, 2021. https://scholar.colorado.edu/ecen_gradetds/49.

MLA Handbook (7^th Edition):

Vaze, Chinmay Shankar. “Degrees of Freedom of Single-hop and Multi-hop MIMO Interference Networks with Feedback and Cooperation.” 2012. Web. 23 Jan 2021.

Vancouver:

Vaze CS. Degrees of Freedom of Single-hop and Multi-hop MIMO Interference Networks with Feedback and Cooperation. [Internet] [Doctoral dissertation]. University of Colorado; 2012. [cited 2021 Jan 23]. Available from: https://scholar.colorado.edu/ecen_gradetds/49.

Council of Science Editors:

Vaze CS. Degrees of Freedom of Single-hop and Multi-hop MIMO Interference Networks with Feedback and Cooperation. [Doctoral Dissertation]. University of Colorado; 2012. Available from: https://scholar.colorado.edu/ecen_gradetds/49

University of Colorado

12. Matviychuk, Yevgen. Learning and Mapping onto Manifolds with Applications to Patch-based Image Processing.

Degree: PhD, Electrical, Computer & Energy Engineering, 2016, University of Colorado

URL: https://scholar.colorado.edu/ecen_gradetds/124

► While the field of image processing has been around for some time, new applications across many diverse areas, such as medical imaging, remote sensing,… (more)

▼ While the field of image processing has been around for some time, new applications across many diverse areas, such as medical imaging, remote sensing, astrophysics, cellular imaging, computer vision, and many others, continue to demand more and more sophisticated image processing techniques. These areas inherently rely on the development of novel methods and algorithms for their success. Many important cases in these applications can be posed as problems of reversing the action of certain linear operators. Recently, patch-based methods for image reconstruction have been shown to work exceptionally well in addressing these inverse problems, establishing new state-of-the-art benchmarks for many of them, and even approaching estimated theoretical limits of performance. However, there is still space and need for improvement, particularly in highly specialized domains. The purpose of this thesis will be to improve upon these prior patch-based image processing methods by developing a computationally efficient way to model the underlying set of patches as arising from a low-dimensional manifold. In contrast to other works that have attempted to use a manifold model for patches, ours will rely on the machinery of kernel methods to efficiently approximate the solution. This will make our approach much more suitable for practical use than those of our predecessors. We will show experimental results paralleling or exceeding those of modern state-of-the-art image processing algorithms for several inverse problems. Additionally, near the end of the thesis, we will revisit the problem of learning a representation for the manifold from its samples and develop an improved approach for it. In contrast to prior methods for manifold learning, our kernel-based strategy will be robust to issues of learning from very few or noisy samples, and it will readily allow for interpolation along or projection onto the manifold. Advisors/Committee Members: Shannon M. Hughes, Youjian Liu, Lijun Chen, Jem Corcoran, Elizabeth Bradley.

Subjects/Keywords: Image processing; Inverse problems; Kernel methods; Machine learning; Manifold models; Computer Sciences; Electrical and Computer Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Matviychuk, Y. (2016). Learning and Mapping onto Manifolds with Applications to Patch-based Image Processing. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/ecen_gradetds/124

Chicago Manual of Style (16^th Edition):

Matviychuk, Yevgen. “Learning and Mapping onto Manifolds with Applications to Patch-based Image Processing.” 2016. Doctoral Dissertation, University of Colorado. Accessed January 23, 2021. https://scholar.colorado.edu/ecen_gradetds/124.

MLA Handbook (7^th Edition):

Matviychuk, Yevgen. “Learning and Mapping onto Manifolds with Applications to Patch-based Image Processing.” 2016. Web. 23 Jan 2021.

Vancouver:

Matviychuk Y. Learning and Mapping onto Manifolds with Applications to Patch-based Image Processing. [Internet] [Doctoral dissertation]. University of Colorado; 2016. [cited 2021 Jan 23]. Available from: https://scholar.colorado.edu/ecen_gradetds/124.

Council of Science Editors:

Matviychuk Y. Learning and Mapping onto Manifolds with Applications to Patch-based Image Processing. [Doctoral Dissertation]. University of Colorado; 2016. Available from: https://scholar.colorado.edu/ecen_gradetds/124

University of Colorado

13. Li, Xing. Optimization and Performance of MIMO B-MAC Interference Networks.

Degree: PhD, Electrical, Computer & Energy Engineering, 2015, University of Colorado

URL: https://scholar.colorado.edu/ecen_gradetds/118

► This thesis studies optimization and performance of the MIMO B-MAC interference networks which includes broadcast channel (BC), multiaccess channel (MAC), interference channels, X networks,… (more)

▼ This thesis studies optimization and performance of the MIMO B-MAC interference networks which includes broadcast channel (BC), multiaccess channel (MAC), interference channels, X networks, and many practical wireless networks as special cases. A 3D channel model for distributed MIMO system is set up, based on which the antenna correlations can be characterized in analytic form. We propose a new algorithm, named Dual Link algorithm, for the classic problem of weighted sum-rate maximization for MIMO multiaccess channels (MAC), broadcast channels (BC), and general MIMO interference channels with Gaussian input and a total power constraint. For MIMO MAC/BC, the algorithm finds optimal signals to achieve the capacity region boundary. For interference channels with Gaussian input assumption, two of the previous state-of-the-art algorithms are the WMMSE algorithm and the polite water-filling (PWF) algorithm. The WMMSE algorithm is provably convergent, while the PWF algorithm takes the advantage of the optimal transmit signal structure and converges the fastest in most situations but is not guaranteed to converge in all situations. It is highly desirable to design an algorithm that has the advantages of both algorithms. The proposed dual link algorithm is such an algorithm. Its fast and guaranteed convergence is important to distributed implementation and time varying channels. In addition, the technique and a scaling invariance property used in the convergence proof may find applications in other non-convex problems in communication networks. The dual link algorithm is also further modified to fit practical applications. Since the centralized algorithm is not scalable as network size increases, the optimization algorithm needs to be working in a mainly distributed fashion to avoid having huge signaling overheads. We've proposed the distributed dual link algorithm for time division duplex (TDD) interference networks. It replaces direct and cross channel information feedbacks with iterations of forward and reverse link pilots training whose complexity grows linearly with the number of users in the network. By totally avoiding channel state knowledge feedback, the distributed dual link algorithm has significant lower signaling overhead compared to the traditional methods, especially in networks with large number of interfering users. However, the real TDD channels are not reciprocal because the transmit and receive RF chains are different in a transceiver. To solve this issue, we proposed a simple method of channel calibration to restore TDD channel reciprocity for MIMO interference networks that is essential to the distributed implementation of the Dual Link algorithm and other algorithms that require reciprocity. On the other hand, the channel knowledge is generally imperfect in a realistic scenario. To study its impact, we introduce a simple channel uncertainty model that characterizes different levels of channel uncertainty. Based on this model, the ergodic weighted sum-rate maximization problem is studied. The ergodic… Advisors/Committee Members: Youjian Liu, Lijun Chen, Mahesh K. Varanasi, Behrouz Touri, Peter Mathys.

Subjects/Keywords: Duality; Interference Channel; MIMO; Optimization; Weighted Sumrate Maximization; Systems and Communications; Theory and Algorithms

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Li, X. (2015). Optimization and Performance of MIMO B-MAC Interference Networks. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/ecen_gradetds/118

Chicago Manual of Style (16^th Edition):

Li, Xing. “Optimization and Performance of MIMO B-MAC Interference Networks.” 2015. Doctoral Dissertation, University of Colorado. Accessed January 23, 2021. https://scholar.colorado.edu/ecen_gradetds/118.

MLA Handbook (7^th Edition):

Li, Xing. “Optimization and Performance of MIMO B-MAC Interference Networks.” 2015. Web. 23 Jan 2021.

Vancouver:

Li X. Optimization and Performance of MIMO B-MAC Interference Networks. [Internet] [Doctoral dissertation]. University of Colorado; 2015. [cited 2021 Jan 23]. Available from: https://scholar.colorado.edu/ecen_gradetds/118.

Council of Science Editors:

Li X. Optimization and Performance of MIMO B-MAC Interference Networks. [Doctoral Dissertation]. University of Colorado; 2015. Available from: https://scholar.colorado.edu/ecen_gradetds/118

University of Colorado

14. Pang, Yimin. Capacity Approximations of Mimo Interference Channels: Beyond Degrees of Freedom.

Degree: PhD, 2019, University of Colorado

URL: https://scholar.colorado.edu/eeng_gradetds/39

► Spectrum sharing allows the coexistence of heterogeneous wireless networks on the same frequency band. Managing the interference between such networks is critically important to… (more)

▼ Spectrum sharing allows the coexistence of heterogeneous wireless networks on the same frequency band. Managing the interference between such networks is critically important to ensure high spectrum efficiency, thus motivating the study of multiple-input-multiple-output (MIMO) interference channels (IC) in information theory. This dissertation studies three classes of such interference channels, namely, the MIMO one-to-three IC, the MIMO IC-ZIC, and the MIMO MAC-IC-MAC. The MIMO one-to-three IC is a partially connected three-user IC with multiple antenna terminals, where one transmitter that causes interference is heard at all three receivers, whereas the other two transmitters are heard only by their intended receivers. We present inner and outer bounds on the capacity region of the MIMO one-to-three IC, quantify the gap between the two bounds, and show that the gap is independent of the channel signal-to-noise ratios (SNRs) and interference-to-noise ratios (INRs). In particular, the achievable scheme at the interfering transmitter involves three-level superposition coding with linear precoding based on the generalized singular value decomposition (GSVD) whereas the non-interfering transmitters perform single-user coding with Gaussian codebooks and scaled identity covariances. The outer bound is obtained using genie-aided arguments with various combinations of genie information provided to the receivers. The generalized degrees of freedom (GDoF) region, which can be seen as a high SNR approximation of the capacity region, of the MIMO one-to-three IC is then fully characterized. We study the achievability of the GDoF region and the sum GDoF curve using an analysis tool developed in this dissertation, which we refer to as multidimensional signal-level partitioning. This tool is tailored for demonstrating the achievability of GDoF-tuples of a MIMO network that can be achieved via multi-level superposition coding. The MIMO IC-ZIC is also a partially connected three-user IC consisting of three transmitter-receiver pairs. In the IC-ZIC, the first and second pairs form a two-user IC, the first and third pairs form a one-sided or Z interference channel (ZIC) and the second and third transmitter-receiver pairs taken by themselves are two non-interfering point-to-point links. In this thesis, an explicit inner bound is obtained via a coding scheme is proposed in which the first transmitter employs three-level superposition coding (as in the MIMO one-to-three IC), the second one employs the previously proposed and well-known Karmakar-Varanasi coding scheme (which achieves a constant-gap-to-capacity region of the two-user MIMO IC), and the third transmitter employs single-user coding with a Gaussian codebook (with scaled identity covariance). An explicit single region outer bound based on genie-aided arguments is then obtained. The gap between the inner and outer bounds is then shown to be within a quantifiable gap to the capacity region and the gap is independent of channel SNRs and INRs. The GDoF region is then… Advisors/Committee Members: Mahesh Varanasi, Youjian Liu, Fabio Somenzi, Lijun Chen, Sriram Sankaranarayanan.

Subjects/Keywords: generalized degrees of freedom; ic-zic; interference channel; mac-ic-mac; mimo; one-to-three; Electrical and Computer Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Pang, Y. (2019). Capacity Approximations of Mimo Interference Channels: Beyond Degrees of Freedom. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/eeng_gradetds/39

Chicago Manual of Style (16^th Edition):

Pang, Yimin. “Capacity Approximations of Mimo Interference Channels: Beyond Degrees of Freedom.” 2019. Doctoral Dissertation, University of Colorado. Accessed January 23, 2021. https://scholar.colorado.edu/eeng_gradetds/39.

MLA Handbook (7^th Edition):

Pang, Yimin. “Capacity Approximations of Mimo Interference Channels: Beyond Degrees of Freedom.” 2019. Web. 23 Jan 2021.

Vancouver:

Pang Y. Capacity Approximations of Mimo Interference Channels: Beyond Degrees of Freedom. [Internet] [Doctoral dissertation]. University of Colorado; 2019. [cited 2021 Jan 23]. Available from: https://scholar.colorado.edu/eeng_gradetds/39.

Council of Science Editors:

Pang Y. Capacity Approximations of Mimo Interference Channels: Beyond Degrees of Freedom. [Doctoral Dissertation]. University of Colorado; 2019. Available from: https://scholar.colorado.edu/eeng_gradetds/39

University of Colorado

15. Madhusudhanan, Prasanna. Stochastic Geometric Modeling and Analysis of Wireless Communications Systems.

Degree: PhD, Electrical, Computer & Energy Engineering, 2013, University of Colorado

URL: https://scholar.colorado.edu/ecen_gradetds/69

► This thesis studies the interference performance of large-scale wireless communications systems. Mathematical models are developed for ad-hoc networks, cellular networks, multi-tier (heterogeneous cellular) networks,… (more)

Subjects/Keywords: Fading Channels; Interference characteristics; Massive MIMO; Poisson processes; Stochastic geometry; Wireless communications; Electrical and Computer Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Madhusudhanan, P. (2013). Stochastic Geometric Modeling and Analysis of Wireless Communications Systems. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/ecen_gradetds/69

Chicago Manual of Style (16^th Edition):

Madhusudhanan, Prasanna. “Stochastic Geometric Modeling and Analysis of Wireless Communications Systems.” 2013. Doctoral Dissertation, University of Colorado. Accessed January 23, 2021. https://scholar.colorado.edu/ecen_gradetds/69.

MLA Handbook (7^th Edition):

Madhusudhanan, Prasanna. “Stochastic Geometric Modeling and Analysis of Wireless Communications Systems.” 2013. Web. 23 Jan 2021.

Vancouver:

Madhusudhanan P. Stochastic Geometric Modeling and Analysis of Wireless Communications Systems. [Internet] [Doctoral dissertation]. University of Colorado; 2013. [cited 2021 Jan 23]. Available from: https://scholar.colorado.edu/ecen_gradetds/69.

Council of Science Editors:

Madhusudhanan P. Stochastic Geometric Modeling and Analysis of Wireless Communications Systems. [Doctoral Dissertation]. University of Colorado; 2013. Available from: https://scholar.colorado.edu/ecen_gradetds/69

University of Colorado

16. Wang, Yao. Degrees of Freedom of MIMO Wireless Networks with General Message Sets: Channel Decomposition, Message Splitting and Beamformer Allocation.

Degree: PhD, 2017, University of Colorado

URL: https://scholar.colorado.edu/ecen_gradetds/185

► The physical layer of a wireless network can be used in various settings distinguished by the specific set of messages transmitted in the network.… (more)

▼ The physical layer of a wireless network can be used in various settings distinguished by the specific set of messages transmitted in the network. In this thesis, rather than considering each setting in isolation as has been the traditional approach, we study the unified setting of general message sets in which any subset (including all) of messages can be transmitted simultaneously in a network. The total number of possible messages is exponential in the size of the network and the number of settings simultaneously studied is double-exponential. For this reason, the problem quickly would become difficult or even impossible to solve for large networks unless some structure is found in smaller network settings. In this thesis, we begin this journey by settling the approximate capacity regions in the form of exact degrees of freedom (DoF) or the linear DoF regions of selected small, but representative, multiple-input multiple-output (MIMO) wireless broadcast and interference networks. The aim is to not only develop novel approaches to fully obtain the DoF-optimal solutions through tight inner and outer bounds but also to suggest approaches that could be potentially useful in generalizing the results herein to a broader class of problems that may include larger networks and/or channel uncertainty models. In developing novel achievable schemes, we propose a methodology that combines the idea of message splitting and channel decomposition, which notably simplifies the construction of the achievable region for the network. Using channel decomposition, the transmitter beamformer space is partitioned into several linearly independent subspaces, each of which has special properties and is easier to analyze. Message splitting involves expanding the number of message types beyond the original ones by splitting each message into several independent types according to their different impacts to the receivers or which beamformer subspaces they are transmitted through. This enlarges the dimensions needed to specify the achievable DoF region in split-message space. Interestingly though, it also simplifies the analysis and provides what is effectively a high-dimensional description of the achievable DoF region. When projected to the desired dimensions, the achievable region is specified. Advisors/Committee Members: Mahesh K. Varanasi, David R. Grant, Dejan S. Filipovic, Peter Mathys, Youjian Liu.

Subjects/Keywords: beamformer allocation; channel decomposition; degrees of freedom; general message sets; message splitting; multiple-input multiple-output; Electrical and Computer Engineering; Management Information Systems

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Wang, Y. (2017). Degrees of Freedom of MIMO Wireless Networks with General Message Sets: Channel Decomposition, Message Splitting and Beamformer Allocation. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/ecen_gradetds/185

Chicago Manual of Style (16^th Edition):

Wang, Yao. “Degrees of Freedom of MIMO Wireless Networks with General Message Sets: Channel Decomposition, Message Splitting and Beamformer Allocation.” 2017. Doctoral Dissertation, University of Colorado. Accessed January 23, 2021. https://scholar.colorado.edu/ecen_gradetds/185.

MLA Handbook (7^th Edition):

Wang, Yao. “Degrees of Freedom of MIMO Wireless Networks with General Message Sets: Channel Decomposition, Message Splitting and Beamformer Allocation.” 2017. Web. 23 Jan 2021.

Vancouver:

Wang Y. Degrees of Freedom of MIMO Wireless Networks with General Message Sets: Channel Decomposition, Message Splitting and Beamformer Allocation. [Internet] [Doctoral dissertation]. University of Colorado; 2017. [cited 2021 Jan 23]. Available from: https://scholar.colorado.edu/ecen_gradetds/185.

Council of Science Editors:

Wang Y. Degrees of Freedom of MIMO Wireless Networks with General Message Sets: Channel Decomposition, Message Splitting and Beamformer Allocation. [Doctoral Dissertation]. University of Colorado; 2017. Available from: https://scholar.colorado.edu/ecen_gradetds/185

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Open Access Theses and Dissertations