Multiple hyperplane detector for implementing the asymptotic Bayesian decision feedback equalizer

A detector based on multiple-hyperplane partitioning of the signal space is derived for realizing the Bayesian decision feedback equaliser (DFE). It is known that the optimal Bayesian decision boundary separating any two neighbouring signal classes is asymptotically piecewise linear and consists of several hyperplanes, when the signal to noise ratio (SNR) tends to infinity. The proposed technique determines these hyperplanes and uses them to partition the observation space. The resulting detector can closely approximate the optimal Bayesian detector, at an advantage of considerably reduced decision complexity

Proceedings of the 35th WIC Symposium on Information Theory in the Benelux and the 4th joint WIC/IEEE Symposium on Information Theory and Signal Processing in the Benelux, Eindhoven, the Netherlands May 12-13, 2014

Compressive sensing (CS) as an approach for data acquisition has recently received much attention. In CS, the signal recovery problem from the observed data requires the solution of a sparse vector from an underdetermined system of equations. The underlying sparse signal recovery problem is quite general with many applications and is the focus of this talk. The main emphasis will be on Bayesian approaches for sparse signal recovery. We will examine sparse priors such as the super-Gaussian and student-t priors and appropriate MAP estimation methods. In particular, re-weighted l2 and re-weighted l1 methods developed to solve the optimization problem will be discussed. The talk will also examine a hierarchical Bayesian framework and then study in detail an empirical Bayesian method, the Sparse Bayesian Learning (SBL) method. If time permits, we will also discuss Bayesian methods for sparse recovery problems with structure; Intra-vector correlation in the context of the block sparse model and inter-vector correlation in the context of the multiple measurement vector problem

Recent Advances in Wireless Communications and Networks

This book focuses on the current hottest issues from the lowest layers to the upper layers of wireless communication networks and provides "real-time" research progress on these issues. The authors have made every effort to systematically organize the information on these topics to make it easily accessible to readers of any level. This book also maintains the balance between current research results and their theoretical support. In this book, a variety of novel techniques in wireless communications and networks are investigated. The authors attempt to present these topics in detail. Insightful and reader-friendly descriptions are presented to nourish readers of any level, from practicing and knowledgeable communication engineers to beginning or professional researchers. All interested readers can easily find noteworthy materials in much greater detail than in previous publications and in the references cited in these chapters

OFDM under Oscillator Phase Noise : Contributions to Analysis and Estimation Methods

Most modern transmitters and receivers involve an analog front-end unit and a digital back-end unit. The digital back-end is responsible for information processing which involves thefollowing: redundancy removal from information; information representation; improvinginformation resilience; and information correction. The analog front-end is responsible forinformation transmission and reception. The information processing algorithms developedand implemented in the digital back-end assume a linear and noiseless analog front-end which,in reality, is not the case. This renders some of the information processing algorithms to be lesseffective in practice. The focus of this thesis is on orthogonal frequency-division multiplexing(OFDM) systems under the influence of oscillator phase noise. OFDM is an efficientinformation representation technique used in many communication systems. On the otherhand, phase noise is one type of undesired noise that occurs in the oscillator device used in theanalog front-end. It arises due to the imperfect task of frequency conversion, performed by theoscillator device, between baseband and radio frequency.  This thesis contributes to the areas of analysis and estimation in OFDM systems under theinfluence of oscillator phase noise. With regard to analysis, this thesis contributes by derivingthe channel capacity assuming a Gaussian input alphabet. The aim here is to show bothquantitatively and qualitatively the degradation in performance of the OFDM system in thepresence of phase noise. The analysis is conducted for phase noise processes that occur in bothfree-running and phase-locked loop based oscillators and also extended to include the effect ofcarrier frequency offset. With regard to estimation, two new phase noise estimation algorithmsare proposed in this thesis. In particular, these algorithms restrict the search space to a specific subset, where the desired phase noise parameter of interest is shown to lie. For example, in the first estimation method, possible subspaces in which the desired phase noise spectral vector may lie are used in the estimation step. In the second method, the geometry of the desired phase noise spectral vector is used in the estimation step. Specifically, this geometry corresponds to a non-convex set described by a set of quadratic forms that involve permutation matrices. By restricting the search space to this set, the accuracy of phase noise estimation can be improved

Cognitive Radio Systems

Cognitive radio is a hot research area for future wireless communications in the recent years. In order to increase the spectrum utilization, cognitive radio makes it possible for unlicensed users to access the spectrum unoccupied by licensed users. Cognitive radio let the equipments more intelligent to communicate with each other in a spectrum-aware manner and provide a new approach for the co-existence of multiple wireless systems. The goal of this book is to provide highlights of the current research topics in the field of cognitive radio systems. The book consists of 17 chapters, addressing various problems in cognitive radio systems

D13.1 Fundamental issues on energy- and bandwidth-efficient communications and networking

Deliverable D13.1 del projecte europeu NEWCOM#The report presents the current status in the research area of energy- and bandwidth-efficient communications and networking and highlights the fundamental issues still open for further investigation. Furthermore, the report presents the Joint Research Activities (JRAs) which will be performed within WP1.3. For each activity there is the description, the identification of the adherence with the identified fundamental open issues, a presentation of the initial results, and a roadmap for the planned joint research work in each topic.Preprin