Probability Distributions.- Linear Models for Regression.- Linear Models for Classification.- Neural Networks.- Kernel Methods.- Sparse Kernel Machines.- Graphical Models.- Mixture Models and EM.- Approximate Inference.- Sampling Methods.- Continuous Latent Variables.- Sequential Data.- Combining Models.

Pattern Recognition and Machine Learning

A review and tutorial of the fundamental ideas and methods of joint time-frequency distributions is presented. The objective of the field is to describe how the spectral content of a signal changes in time and to develop the physical and mathematical ideas needed to understand what a time-varying spectrum is. The basic gal is to devise a distribution that represents the energy or intensity of a signal simultaneously in time and frequency. Although the basic notions have been developing steadily over the last 40 years, there have recently been significant advances. This review is intended to be understandable to the nonspecialist with emphasis on the diversity of concepts and motivations that have gone into the formation of the field. >

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Time-frequency distributions-a review

Radio frequency (RF) energy transfer and harvesting techniques have recently become alternative methods to power the next-generation wireless networks As this emerging technology enables proactive energy replenishment of wireless devices, it is advantageous in supporting applications with quality-of-service requirements In this paper, we present a comprehensive literature review on the research progresses in wireless networks with RF energy harvesting capability, which is referred to as RF energy harvesting networks (RF-EHNs) First, we present an overview of the RF-EHNs including system architecture, RF energy harvesting techniques, and existing applications Then, we present the background in circuit design as well as the state-of-the-art circuitry implementations and review the communication protocols specially designed for RF-EHNs We also explore various key design issues in the development of RF-EHNs according to the network types, ie, single-hop networks, multiantenna networks, relay networks, and cognitive radio networks Finally, we envision some open research directions

Wireless Networks With RF Energy Harvesting: A Contemporary Survey

Array processing involves manipulation of signals induced on various antenna elements. Its capabilities of steering nulls to reduce cochannel interferences and pointing independent beams toward various mobiles, as well as its ability to provide estimates of directions of radiating sources, make it attractive to a mobile communications system designer. Array processing is expected to play an important role in fulfilling the increased demands of various mobile communications services. Part I of this paper showed how an array could be utilized in different configurations to improve the performance of mobile communications systems, with references to various studies where feasibility of apt array system for mobile communications is considered. This paper provides a comprehensive and detailed treatment of different beam-forming schemes, adaptive algorithms to adjust the required weighting on antennas, direction-of-arrival estimation methods-including their performance comparison-and effects of errors on the performance of an array system, as well as schemes to alleviate them. This paper brings together almost all aspects of array signal processing.

/pdf/application-of-antenna-arrays-to-mobile-communications-ii-52fds1c81j.pdf

Application of antenna arrays to mobile communications. II. Beam-forming and direction-of-arrival considerations

An emerging solution for prolonging the lifetime of energy constrained relay nodes in wireless networks is to avail the ambient radio-frequency (RF) signal and to simultaneously harvest energy and process information. In this paper, an amplify-and-forward (AF) relaying network is considered, where an energy constrained relay node harvests energy from the received RF signal and uses that harvested energy to forward the source information to the destination. Based on the time switching and power splitting receiver architectures, two relaying protocols, namely, i) time switching-based relaying (TSR) protocol and ii) power splitting-based relaying (PSR) protocol are proposed to enable energy harvesting and information processing at the relay. In order to determine the throughput, analytical expressions for the outage probability and the ergodic capacity are derived for delay-limited and delay-tolerant transmission modes, respectively. The numerical analysis provides practical insights into the effect of various system parameters, such as energy harvesting time, power splitting ratio, source transmission rate, source to relay distance, noise power, and energy harvesting efficiency, on the performance of wireless energy harvesting and information processing using AF relay nodes. In particular, the TSR protocol outperforms the PSR protocol in terms of throughput at relatively low signal-to-noise-ratios and high transmission rates.

https://openresearch-repository.anu.edu.au/bitstream/1885/11605/3/Nasir%20et%20al%20Relaying%20protocols%202013.pdf

Relaying Protocols for Wireless Energy Harvesting and Information Processing

A coprime array uses two uniform linear subarrays to construct an effective difference coarray with certain desirable characteristics, such as a high number of degrees-of-freedom for direction-of-arrival (DOA) estimation. In this paper, we generalize the coprime array concept with two operations. The first operation is through the compression of the inter-element spacing of one subarray and the resulting structure treats the existing variations of coprime array configurations as well as the nested array structure as its special cases. The second operation exploits two displaced subarrays, and the resulting coprime array structure allows the minimum inter-element spacing to be much larger than the typical half-wavelength requirement, making them useful in applications where a small interelement spacing is infeasible. The performance of the generalized coarray structures is evaluated using their difference coarray equivalence. In particular, we derive the analytical expressions for the coarray aperture, the achievable number of unique lags, and the maximum number of consecutive lags for quantitative evaluation, comparison, and design of coprime arrays. The usefulness of these results is demonstrated using examples applied for DOA estimations utilizing both subspace-based and sparse signal reconstruction techniques.

/pdf/generalized-coprime-array-configurations-for-direction-of-9hap9qma4c.pdf

Generalized Coprime Array Configurations for Direction-of-Arrival Estimation

Blind source separation consists of recovering a set of signals of which only instantaneous linear mixtures are observed. Thus far, this problem has been solved using statistical information available on the source signals. This paper introduces a new blind source separation approach exploiting the difference in the time-frequency (t-f) signatures of the sources to be separated. The approach is based on the diagonalization of a combined set of "spatial t-f distributions". In contrast to existing techniques, the proposed approach allows the separation of Gaussian sources with identical spectral shape but with different t-f localization properties. The effects of spreading the noise power while localizing the source energy in the t-f domain amounts to increasing the robustness of the proposed approach with respect to noise and, hence, improved performance. Asymptotic performance analysis and numerical simulations are provided.

Blind source separation based on time-frequency signal representations

We develop a new technique for a dual-function system with joint radar and communication platforms. Sidelobe control of the transmit beamforming in tandem with waveform diversity enables communication links using the same pulse radar spectrum. Multiple simultaneously transmitted orthogonal waveforms are used for embedding a sequence of LB bits during each radar pulse. Two weight vectors are designed to achieve two transmit spatial power distribution patterns, which have the same main radar beam, but differ in sidelobe levels towards the intended communication receivers. The receiver interpretation of the bit is based on its radiated beam. The proposed technique allows information delivery to single or multiple communication directions outside the mainlobe of the radar. It is shown that the communication process is inherently secure against intercept from directions other than the pre-assigned communication directions. The employed waveform diversity scheme supports a multiple-input multiple-output radar operation mode. The performance of the proposed technique is investigated in terms of the bit error rate.

Dual-Function Radar-Communications: Information Embedding Using Sidelobe Control and Waveform Diversity

Wall Attenuation and Dispersion, A. Hussein Muqaibel, M.A. Alsunaidi, Nuruddeen M. Iya, and A. Safaai-Jazi Antenna Elements, Arrays, and Systems for Through-the-Wall Radar Imaging, A. Hoorfar and A. Fathy Beamforming for Through-the-Wall Radar Imaging, G. Alli and D. DiFilippo Image and Localization of Behind-the-Wall Targets Using Collocated and Distributed Apertures, Y.D. Zhang and A. Hunt Conventional and Emerging Waveforms for Detection and Imaging of Targets behind Walls, F. Ahmad and R.M. Narayanan Inverse Scattering Approaches in Through-the-Wall Imaging, K. Sarabandi, M. Thiel, M. Dehmollaian, R. Solimene, and F. Soldovieri Through-the-Wall Microwave Building Tomography, P.B. Weichman, E.M. Lavely, E.H. Hill III, and P. Zemany Analytical Ray Methods for Through-the-Wall Radar Imaging, R.J. Burkholder, R.J. Marhefka, and J.L. Volakis Synthetic Aperture Radar Techniques for Through-the-Wall Imaging, T. Dogaru and C. Le Impulse SAR and Its Application for Through-the-Wall Detection and Identification of People and Weapons, J.Z. Tatoian Through-the-Wall SAR for Characterization of Building Interior Structure Using Attributed Scattering Center Features, E. Ertin and R.L. Moses Detection Approaches in Through-the-Wall Radar Imaging, C. Debes and A.M. Zoubir Detection of Concealed Targets in Through-the-Wall Imaging, L. Crocco Fast Acquisition and Compressive Sensing Techniques for Through-the-Wall Radar Imaging, M. Amin, Y-S. Yoon, and S. Kassam Radar Micro-Doppler Signatures for Characterization of Human Motion, V.C. Chen, G.E. Smith, K. Woodbridge, and C.J. Baker Index

Through-the-Wall Radar Imaging

In this paper, we propose co-prime arrays for effective direction-of-arrival (DOA) estimation. To fully utilize the virtual aperture achieved in the difference co-array constructed from a co-prime array structure, sparsity-based spatial spectrum estimation technique is exploited. Compared to existing techniques, the proposed technique achieves better utilization of the co-array aperture and thus results in increased degrees-of-freedom as well as improved DOA estimation performance.

/pdf/sparsity-based-doa-estimation-using-co-prime-arrays-s38ix4aya7.pdf

Moeness G. Amin

Papers

Generalized Coprime Array Configurations for Direction-of-Arrival Estimation

Blind source separation based on time-frequency signal representations

Dual-Function Radar-Communications: Information Embedding Using Sidelobe Control and Waveform Diversity

Through-the-Wall Radar Imaging

Sparsity-based DOA estimation using co-prime arrays