Engineering Commons^™

Augmented Communications : A Solution For Overcoming High Spatial Correlation Of The Massive-Miso Vlc Channel, Monette Khadr

Legacy Theses & Dissertations (2009 - 2024)

A key challenge for future wireless networks is to come upon a riveting compromise between spectral efficiency, complexity, and energy efficiency. The challenge is also intensified due to the pace at which the Internet-of-Things (IoT) technology is arriving, causing an upheaval to pre-existing network infrastructures in terms of elevating spectrum scarcity. To keep pace with the exploding data demand forecasts, a circumvention is required. One realization is by utilizing the high-band spectrum and the rich body of knowledge on multiple-input multiple-output (MIMO) technologies. One of the prominent high frequency technologies is visible light communications (VLC). VLC provide a large unregulated …

Bibliometric Survey On Reconfigurable Antenna For Mimo Systems, Priyanka Tupe-Waghmare, Sanjeev Kumar Prof.

Library Philosophy and Practice (e-journal)

The aim of this study is to analyse the work done on the frequency and polarization reconfigurability of antenna for various design types using the bibliometric study methods. Different articles on reconfigurable antennas for MIMO systems were retrieved using SCOPUS which is one of the most popular databases. The research articles published between 2004 to 2020 were considered and Scopus Analyser was used to fetch the analysis results namely document by source, author, subject, year and country. In the currently available literature, a lot of survey articles on the reconfigurable antennas and MIMO systems is available but there is no …

A Hybrid Multiband Printed Loop Antenna For Wlan/Wimax Bands For Applications In Mimo Systems, Ali Shahshahani, Mohammad Amin Honarvar

Turkish Journal of Electrical Engineering and Computer Sciences

In this article a thin hybrid multiband printed loop antenna is presented for application in multiple-input multiple-output (MIMO) systems. The proposed antenna has several advantages; for example, the pseudofilter feature of the proposed antenna is one of this antenna's advantages. Because of the antenna's width ($9.5$~mm), it can be used on the edges of the board. The first resonant frequency is generated by the original loop of the antenna. Incorporation of different embedded components, i.e. a subsidiary loop, extended ground-traces, parasitic patch, and the slits, results in the proposed antenna resonating as a multiband antenna. This antenna is adjusted in …

The Effects Of Antenna Coupling In A Mimo Radar System, Benjamin T. Arnold

Theses and Dissertations

A mathematical model for a multiple-input multiple-output radar system is presented. The model is used to track signals through the system in order to identify the impact of antenna array mutual coupling on radar system performance. Simulations using the model provide quantitative assessment of the performance degradation as a function of antenna coupling strength. Specifically, the results show that coupling can cause a target to appear at an angle notably different than its actual angle and can cause an increase in the side lobe level. A compensation technique is presented that completely removes these effects for practical levels of coupling. …

Covariance Modeling And Space-Time Coding For Mimo Systems, Farnaz Karimdady Sharifabad

Theses and Dissertations

The full spatial covariance matrix of the multiple input multiple-output (MIMO) channel is an important quantity in channel modeling, communication system signal processing, and performance analysis, and therefore this matrix forms the heart of the research outlined in this dissertation. The work begins with an investigation of a generalized framework for computing the full MIMO spatial covariance based on the power angular spectrum (PAS) of the multipath field and the transmit and receive antenna element radiation patterns. For the case of uniform linear arrays and when the PAS clusters satisfy uniform, truncated Gaussian, or truncated Laplacian distributions, a series expansion …

A Learning Approach In Link Adaptation For Mimo-Ofdm Systems, Hali̇l Yi̇ği̇t, Adnan Kavak

Turkish Journal of Electrical Engineering and Computer Sciences

We propose a neural network (NN)-based adaptive modulation and coding (AMC) for link adaptation in MIMO-OFDM systems. The AMC optimizes the best modulation and coding scheme (MCS) under a packet error rate (PER) constraint. In our approach, a NN with a multilayer perceptron (MLP) structure is applied for the AMC and its performance is compared with the k-nearest neighbor (k-NN) algorithm under the frequency-flat (1-tap) and frequency-selective (4-tap) wireless channel conditions. The simulation results show that the NN classifier outperforms the k-NN algorithm, especially in terms of the PER, due to the fact that the MLP guarantees a MCS with …

Application Of Multi-Input Multi-Output Feedback Control For F-16 Ventral Fin Buffet Alleviation Using Piezoelectric Actuators, Tomoyuki D. Ono

Theses and Dissertations

Control of structural vibrations has been a popular topic. Use of MFC piezoelectric actuators and co-located sensors allows for an active rather than passive control method. The F-16 ventral fin is susceptible to buffet induced vibrations and is a perfect test structure for active vibration control for flight-testing. The research follows the previous ACTIVE FIN project and improves on the design by increasing the number of actuator layers, available actuator power, and using multi-input multi-output (MIMO) control algorithms. The research involved experimental identification of the ventral fin and its principle strain directions, selection of system components, determination of mathematical plant …

Trade-Offs In A 1 Tbps Mimo Communication System Between An Airship And An Array Of Ground Receive Antennas, Adam R. Brueggen

Theses and Dissertations

As demand for higher data-rate wireless communications increases, so will the interest in multiple-input and multiple-output (MIMO) systems. In a single transmitter, single receiver communication system, there is a fundamental limit to the data-rate capacity of the system proportional to the systems bandwidth. Since increasing the bandwidth is expensive and limited, another option is increasing the system's capacity by adding multiple antennas at the transmitter and receiver to create a MIMO communication system. With a T transmitter, R receiver MIMO communication system, TR channels are created which allow extremely high data-rates. MIMO systems are attractive because they are extremely robust …

Secret Key Establishment Using Wireless Channels As Common Randomness In Time-Variant Mimo Systems, Chan Chen

Theses and Dissertations

Encryption of confidential data with a secret key has become a widespread technique for securing wireless transmissions. However, existing key distribution methods that either deliver the secret key with a key distribution center or exchange the secret key using public-key cryptosystems are unable to establish perfect secret keys necessary for symmetric encryption techniques. This research considers secret key establishment, under the broad research area of information theoretic security, using the reciprocal wireless channel as common randomness for the extraction of perfect secret keys in multiple-input multiple-output (MIMO)communication systems. The presentation discusses the fundamental characteristics of the time-variant MIMO wireless channel …

Reduced-Feedback Linear Precoding With Stable Performance For The Time-Varying Mimo Broadcast Channel, Michael A. Jensen, Adam L. Anderson, James R. Zeidler

Faculty Publications

This work explores the performance of a multiple-input multiple-output broadcast channel where both the transmitter and receivers have outdated channel knowledge due to node motion or other time-variations in the communication channel. A performance analysis based on measured channel responses reveals significant throughput degradation for optimal linear and nonlinear precoding strategies unless the channel state information (CSI) is frequently fed back to the transmitter. The paper then develops a linear beamforming precoding strategy based on channel distribution information in the form of a full spatial correlation matrix for each user. This algorithm is shown to provide highly stable communication, with …

Multiple-Input Multiple-Output Rayleigh Flat Fading Outage Capacity Using Channel Estimation, Chris G. Potter, Kurt Louis Kosbar, Adam Panagos

Electrical and Computer Engineering Faculty Research & Creative Works

Upper and lower bounds on the outage capacity for a multiple-input multiple-output (MIMO) Rayleigh flat fading wireless baseband communication environment are derived for the case when the channel is completely unknown at the transmitter and the receiver has access to channel state information (CSI) via pilot estimation. The bounds show that the channel estimation error significantly impacts the outage capacity. A change in the outage probability is also shown to have a larger impact on the outage capacity when the channel estimation error is small. To get an idea of how these bounds are affected by a temporally correlated channel, …

Cross-Layer Issues In Mac Protocol Design For Mimo Ad Hoc Networks, Michael A. Jensen, A. Lee Swindlehurst, Michele Zorzi, James R. Zeidler, Adam L. Anderson, Bhaskar Rao, John Proakis, Srikanth Krishnamurthy

Faculty Publications

In this article, we discuss research and design issues that arise in the development of networking protocols for an ad hoc network where nodes are equipped with multiple antenna elements and have the ability to perform signal processing operations as required by adaptive beamforming, interference cancellation, and space-time coding.

Reinforcement Learning-Based Output Feedback Control Of Nonlinear Systems With Input Constraints, Pingan He, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

A novel neural network (NN) -based output feedback controller with magnitude constraints is designed to deliver a desired tracking performance for a class of multi-input-multi-output (MIMO) discrete-time strict feedback nonlinear systems. Reinforcement learning in discrete time is proposed for the output feedback controller, which uses three NN: 1) a NN observer to estimate the system states with the input-output data; 2) a critic NN to approximate certain strategic utility function; and 3) an action NN to minimize both the strategic utility function and the unknown dynamics estimation errors. The magnitude constraints are manifested as saturation nonlinearities in the output feedback …

Turbo Space-Time Coding For Mimo Systems : Designs And Analyses, Hangjun Chen

Dissertations

Multiple input multiple output (MIMO) systems can provide high diversity, high data rate or a mix of both, for wireless communications. This dissertation combines both modes and suggests analyses and techniques that advance the state of the art of MIMO systems. Specifically, this dissertation studies turbo space-time coding schemes for MIMO systems.

Before the designs of turbo space-time codes are presented, a fundamental tool to analyze and design turbo coding schemes, the extrinsic information transfer (EXIT) chart method, is extended from the binary/nonbinary code case to coded modulation case. This extension prepares the convergence analysis for turbo space-time code.

Turbo …

Efficient Capacity-Based Antenna Selection For Mimo Systems, Michael A. Jensen, Matthew L. Morris

Faculty Publications

The achieved capacity of the multiple-input-multiple-output wireless channel is typically dependent on the array configurations at the transmitter and receiver. Maximizing system capacity or throughput therefore requires that the arrays adapt to changing channel conditions, which may be accomplished by selecting an appropriate subset of available antenna elements for connection to the electronic transmit and receive modules. This work presents algorithms, derived using relatively straightforward information theoretic considerations, for efficiently and effectively selecting the antenna elements. Computational examples using a realistic channel model for indoor environments illustrate the performance of the techniques.

Network Model For Mimo Systems With Coupled Antennas And Noisy Amplifiers, Michael A. Jensen, Matthew L. Morris

Faculty Publications

This work presents a framework for the analysis of mutually-coupled antennas in a multiple-input multiple-output system. The approach uses network theory to formulate the transfer matrix relating the signals input to the transmit antennas to the signals at the output of the receiver front end. This transfer function includes the coupled transmit and receive antennas, the multipath propagation channel, the receiver matching network, and a realistic noise model for the receive amplifiers. Application of the formulation to coupled dipole antennas characterized using full-wave electromagnetic analysis illustrates the performance gains possible from matching the coupled antenna/receive amplifier subsystem for minimum noise …

Mutual Coupling In Mimo Wireless Systems: A Rigorous Network Theory Analysis, Michael A. Jensen, Jon W. Wallace

Faculty Publications

A new framework for the analysis of multiple-input multiple-output (MIMO) wireless systems is introduced to account for mutual coupling effects in the antenna arrays. The multiport interactions at transmit and receive are characterized by representing the channel using a scattering parameter matrix. A new power constraint that limits the average radiated power is also introduced. The capacity of the MIMO system with mutual coupling is defined as the maximum mutual information of the transmit and receive vectors over all possible transmit signaling and receive loading. Full-wave electromagnetic antenna simulations combined with a simple path-based channel model are used to demonstrate …

Analysis Of Electromagnetic Field Polarizations In Multi-Antenna Systems, Michael A. Jensen, Jon W. Wallace, Thomas Svantesson

Faculty Publications

This paper provides an analytical framework useful for assessing the use of all six electric and magnetic electromagnetic field polarizations for multiantenna communications systems. The approach uses a mapping between the induced signal currents and the received electromagnetic field in order to formulate a diversity interpretation of the six-polarization problem. Application of the framework to a simple, yet representative, channel model demonstrates that for full multipath elevation and azimuthal angle spread, six communication modes are theoretically possible. However, to implement the system requires more antenna design work since a straightforward implementation is found to reduce the potential number of modes …

Experimental Characterization Of The Mimo Wireless Channel: Data Acquisition, Analysis, And Modeling, Michael A. Jensen, Jon W. Wallace, A. Lee Swindlehurst, Brian D. Jeffs

Faculty Publications

Detailed performance assessment of space-time coding algorithms in realistic channels is critically dependent upon accurate knowledge of the wireless channel spatial characteristics. This paper presents an experimental measurement platform capable of providing the narrowband channel transfer matrix for wireless communications scenarios. The system is used to directly measure key multiple-input-multiple-output parameters in an indoor environment at 2.45 GHz. Linear antenna arrays of different sizes and construction with up to ten elements at transmit and receive are utilized in the measurement campaign. This data is analyzed to reveal channel properties such as transfer matrix element statistical distributions and temporal and spatial …

Modeling The Indoor Mimo Wireless Channel, Michael A. Jensen, Jon W. Wallace

Faculty Publications

This paper demonstrates the ability of a physically based statistical multipath propagation model to match capacity statistics and pairwise magnitude and phase distributions of measured 4 x 4 and 10 x 10 narrow-band multiple-input multiple-output data (MIMO) at 2.4 GHz. The model is compared to simpler statistical models based on the multivariate complex normal distribution with either complex envelope or power correlation. The comparison is facilitated by computing channel element covariance matrices for fixed sets of multipath statistics. Multipolarization data is used to demonstrate a simple method for modeling dual-polarization arrays.