Master of Science in Electrical Engineering (MSEE), Wright State University, 2023, Electrical Engineering

A method for software-defined radio array calibration is presented. The method implements a matched filter approach to calculate the phase shift between channels. The temporal stability of the system and calibration coefficients are shown through the standard deviation over the course of four weeks. The standard deviation of the phase correction was shown to be less than 2 deg. for most channels in the array and within 8 deg. for the most extreme case. The standard deviation in amplitude scaling was calculated to be less than 0.06 for all channels in the array. The performance of the calibration is evaluated by the antenna gain and the difference from the ideal beam shape for the peak side lobe level and first null depth. For one example data collection, the gain was 61 dB for the array with a maximum difference of 0.2246 dB for the peak side lobe level and 0.3998 dB for the first null depth.

Committee: Michael A. Saville Ph.D. (Advisor); Zhiqiang Wu Ph.D. (Committee Member); Josh Ash Ph.D. (Committee Member) Subjects: Electrical Engineering

Master of Science (MS), Ohio University, 2013, Electrical Engineering (Engineering and Technology)

This thesis presents a demonstrated method for the performance of a calibration method for a controlled reception pattern antenna (CRPA) using a Software Defined Radio (SDR) configuration. The combination CRPA and SDR system consists of a low-cost 7-element configuration where the antenna RF inputs are feed directly into the multi-channel SDR system. This combination CRPA and SDR system was characterized in an anechoic chamber environment to closely replicate the fielded antenna/receiver system. This combined CRPA and SDR system calibration method configuration can provide multi-antenna element characterization and calibration measurements that can be used to remove carrier and code phase biases caused by the antenna elements and receiver front-end components for down-stream adaptive signal processing algorithms. For verification, the calibration data produced by the CRPA/SDR system configuration will be compared with calibration data produced using a traditional CRPA anechoic chamber test approach where each element of the array is characterized one at a time with a traditional antenna test approach.

Committee: Chris G. Bartone PhD (Advisor); Sanjeev Gunawardena PhD (Committee Member); Michael Braasch PhD (Committee Member); David C. Ingram PhD (Committee Member) Subjects: Aerospace Engineering; Electrical Engineering

Master of Science (MS), Ohio University, 2022, Electrical Engineering (Engineering and Technology)

Satnav Software Defined Radios (SDRs) have several advantages over legacy radio architectures, which include flexibility and configurability. An entire satnav SDR system can be described in simple configuration files. While SDRs serve as excellent research and educational tools, oftentimes SDR implementations that run on general purpose processors suffer from performance limitations and slow runtimes. Specifically, satellite timing and navigation (satnav) receivers that process multiple high sample rate data streams can result in such a decreased performance that runtimes become unreasonable. In a satnav SDR, sample decoding, carrier replica generation, carrier wipeoff, and correlation represent the most computationally intensive modules. These modules that benefit from a performance increase can be swapped out for accelerated versions making use of low level programming while leaving the other modules intact. This thesis describes the acceleration of these modules using bitwise parallel processing, SIMD instructions, and multithreading. The significant performance gains obtained through these accelerations strategies (as compared to a naive C++ implementation) captured through extensive benchmarking are presented.

Committee: Michael Braasch (Advisor); Jay Wilhelm (Committee Member); Chad Mourning (Committee Member); Sabrina Ugazio (Committee Member) Subjects: Computer Engineering; Computer Science; Electrical Engineering; Engineering

Doctor of Philosophy (PhD), Ohio University, 2022, Mathematics (Arts and Sciences)

Sufficient dimension reduction (SDR) in regression analysis with response variable y and predictor vector x is focused on reducing the dimension of x to a small number of linear combinations of the components in x. Since the introduction of the inverse regression method, SDR became a very active topic in the literature. When the dimension p of x is increasing with the number of observations n, the traditional SDR methods may not perform well. The purpose of this study is two fold, theoretical and empirical. In the theoretical analysis, I provide a proof for the consistency of a variable selection procedure in sparse single-index models (a special SDR model) through an inverse regression method called CUME. And for the case of multiple linear regression, I obtain the influence functions for estimators of the parameter vector with SCAD and MCP penalties by extending the idea of LASSO influence function. In the empirical aspect, I combine the LASSO-SIR algorithm with the influence function of LASSO to construct a new metric for choosing the penalty parameter for variable selection as an alternative approach to the usual cross-validation method. From the empirical analysis, it was found that the newly proposed influence function-based measure outperforms the traditional cross-validation method in a wide range of settings. Finally, I also propose an algorithm to estimate the structural dimension d of SDR models with large dimension p.

Committee: Wei Lin (Advisor) Subjects: Mathematics; Statistics

Master of Science in Electrical Engineering (MSEE), Wright State University, 2020, Electrical Engineering

Radio Frequency Fingerprinting (RFF) research typically uses expensive, laboratory grade receivers which have high dynamic range, very stable oscillators, large instantaneous bandwidth, multi-rate sampling, etc. In this study, the RFF effectiveness of lower grade receivers is considered. Using software-defined radios (SDRs) of different cost and performance, a linear regression model is developed to predict RFF performance. Unlike two previous studies of SDR effectiveness that used commercial and lab-grade SDRs, the experiment here focused on hobbyist and commercial-grade SDRs (RTL-SDR, B200-mini, N210). A regression model is proposed for a generic SDR. Using a full-factorial experiment matrix, the gain, sample rate, and signal-to-noise ratio (SNR) were selected as the common control factors. The transmit sources were three commercially-available, general purpose, wireless transmitters of the same model. An SDR performance index (SPI) was developed from the percent correct classification using the Random Forest classifier for each SDR and for a generic SDR. The RFF results show that the lower-cost SDRs record the data with enough fidelity to achieve over 90% classification accuracy.

Committee: Michael A. Saville Ph.D., P.E. (Committee Chair); Saiyu Ren Ph.D. (Committee Member); Henry Chen Ph.D. (Committee Member); Joshua N. Ash Ph.D. (Committee Member) Subjects: Electrical Engineering

Doctor of Philosophy (PhD), Wright State University, 2017, Electrical Engineering

With increasing data rates and new communication standards owing to substantial advancements in digitizing and signal processing capabilities over the last century, the radio spectrum is increasingly becoming a finite and expensive resource. Furthermore, radar systems and 5G communication systems have revealed the need for gigahertz-frequency signal generation with flexible frequency planning and minimal spurious emissions. Advanced digital-to-analog converters (DACs), along with associated filtering, are critical enablers of these new systems and play a key role in meeting stringent system requirements. In conventional implementations, however, high quality filters are specific to one frequency band thereby limiting their operational agility. Therefore, a DAC architecture that removes undesired image replicas, mixer sidebands, and harmonic nonlinearities is an essential component for flexible frequency synthesis as it allows for reduced filtering requirements while enabling new software-defined transmitter techniques. This dissertation aims to provide a quantitative study and analysis of a poly-phased, time-interleaved Nyquist radio frequency digital-to-analog converter (Poly-TI-RF-DAC) for use in spectrum-agile and software-defined transmitters. Beginning with the fundamental understanding of high-speed DAC capabilities and limitations, the mathematical and behavioral analyses give insight into the signal, sideband, and image replica locations of the proposed architecture. Additionally, the use of a mixing DAC as the core structure is discussed along with how nonlinearities can be canceled with the appropriate choice of frequency planning.

Committee: John Emmert Ph.D. (Advisor); Waleed Khalil Ph.D. (Advisor); Saiyu Ren Ph.D. (Committee Member); Raymond Siferd Ph.D. (Committee Member); Paul Watson Ph.D. (Committee Member) Subjects: Electrical Engineering

Master of Science (MS), Ohio University, 2016, Electrical Engineering & Computer Science (Engineering and Technology)

Project 25 (P25) radio, now used by at least 33% of public safety agencies in the US, is accessible to only specialized, digital receivers. These receivers, though, are expensive consumer products – starting at $400. As public safety communications remain legal to receive in unencrypted digital form, the current migration to digital radio has simply made these communications less accessible to the public. What's missing from the current ecosystem is a sub-$100 P25 receiver with usability similar to a traditional device – automatic, hands-free operation in a portable package – that makes these communications accessible again with a more affordable price. The result of this research is a device meeting these requirements, made from a $20 RTL-SDR software defined radio, a Raspberry Pi, and a software P25 receiver pipeline. This implementation was evaluated as follows: baseband symbol decoding and frame synchronization accuracies were measured over 4 million random symbols in the presence of varying levels of noise and distortion, and overall performance was compared to a commercial P25 receiver by measuring voice frame muting errors. This evaluation found the baseband symbol decoder had over 89% accuracy down to a 3:1 SNR, and the frame synchronizer had fewer than 0.0001% false positive and false negative errors at 0.001:1 SNR. Compared to the commercial receiver, the de-signed receiver recovered over 95% of voice frames without muting errors. These findings show that recent advances in low-cost software defined radio allow the device to satisfy the above requirements with suitable real-world performance.

Committee: Shawn Ostermann (Advisor) Subjects: Computer Science

Doctor of Philosophy (PhD), Ohio University, 2016, Civil Engineering (Engineering and Technology)

Sedimentation is one of the important factors affecting stream channel stability. The estimation of sediment supply, assessment of channel stability, and potential influencing factors are of interest in this study. A proposed model was developed by the integration of Revised Universal Soil Loss Equation (RUSLE) model and Watershed Assessment of River Stability and Sediment Supply (WARSSS), aiming to estimate the sediment load and evaluate the channel stability of a man-made channel. The proposed model was applied to the channelized Hocking River near Athens, Ohio. It was estimated that the annual gross erosion from the watershed was 728,733,738 kg, 97% of which was from the surface erosion, while only 3% resulted from streambank erosion. The total sediment yield in the channelized Hocking River was indirectly estimated by the addition of suspended sediments and bedload sediments, which were directly measured in the channel. The total annual sediment yield was 80,991,718 kg, in which 98% was estimated from suspended sediments and 2% from bedload sediments. This resulted in a sediment delivery ratio of 11%, which was consistent with those of the watersheds having similar size in the studied region. The total sediment transport capacity was estimated by the proposed model to be 17,161,761 kg/yr. Compared with the total sediment yield of 80,991,718 kg, 21% of which was transported by the river flow. The majority of sediments deposited in the channel due to the insufficient transport capacity. The amount of sediment accumulated was indirectly verified by the annual dredging project conducted by the Hocking Conservancy District (HCD). The channel stability of the Hocking River near Athens, Ohio was assessed by the characteristics of soil erosion for each monitored reach. Based on the four categories of stability determinations, most of the studied reaches were unstable in the lateral direction and all the reaches had excess deposition except one of the downstream r (open full item for complete abstract)

Committee: Tiao Chang (Advisor); Wei Lin (Committee Member); Kurt Rhoads (Committee Member); Teruhisa Masada (Committee Member); Deborah McAvoy (Committee Member) Subjects: Civil Engineering; Water Resource Management

Master of Science in Engineering, Youngstown State University, 2009, Department of Electrical and Computer Engineering

The purpose of this work is to design and implement a low cost and flexible Software Defined Radio platform. Software Defined Radio is an emerging technology that gives engineers and scientists the ability to create reconfigurable wireless technology. Functions that were traditionally performed in hardware are implemented in software, thus making a Software Defined Radio reconfigurable without requiring hardware modifications. Current Software Defined Radio designs are usually based on a personal computer or Field Programmable Gate Array and offer either flexibility at a high cost of implementation or a low cost of implementation that sacrifices flexibility. In this work, a Software Defined Radio platform is presented which offers flexibility with a low cost of implementation. This is achieved by using a personal computer-based architecture with Universal Serial Bus interface to the analog-to-digital conversion and Radio Frequency modules. This external hardware interface, constructed from off the shelf components, provides the versatility for the proposed Software Defined Radio platform at minimal cost. A proof-of-concept design is then implemented and tested, which demonstrates the feasibility of the design.

Committee: Faramarz Mossayebi PhD (Advisor); Frank X. Li PhD (Committee Member); Jalal Jalali PhD (Committee Member) Subjects: Electrical Engineering

Doctor of Philosophy, The Ohio State University, 2011, Electrical and Computer Engineering

With the rapid development of wireless communication systems and increasing wireless communication applications in human life, more and more new communication standards are proposed, which introduce additional frequency bands or modulation schemes. The growing number of wireless communication systems and the increasing demands for bandwidth necessitate the evolvable receiver hardware. To meet this requirement, this work proposes a digitally controlled channelized Software Defined Radio (SDR) architecture which is compatible with most applications in 0.5-10.5 GHz frequency range. In the proposed SDR, the digitally controlled channelized front end divides the entire frequency into seven 1.6 GHz sub bands, and further channelization is realized using a digital filter bank structure so that the proposed SDR could deal with both ultra-wideband and narrow band signals. Link-Budget analysis is performed in the system design, and the detailed specifications for the front end signal processing blocks is provided. A system simulation is performed in ADS to verify the proposed SDR. The circuit design considerations for the proposed SDR system is discussed. The major characteristics of the SDR front end are its ultra-wideband spectrum access, software programmability, and its ability for digitally controlled channelization. The circuit design discussion is focused on those aspects, and gives an idea of some possible design techniques or circuit structures which may be used for the proposed SDR system. Using those techniques, specific circuits are designed as examples, including an LNA with tunable output frequency, an active mixer design with extended IF bandwidth, as well as a quadrature coupler structure with ultra wideband operating frequency range. The simulated results for each circuit block are presented, and the proposed techniques are verified.

Committee: Joanne DeGroat (Advisor); Mohammed Ismail (Committee Member); Steven Bibyk (Committee Member) Subjects: Electrical Engineering

Doctor of Philosophy, The Ohio State University, 2009, Oral Biology

The majority of the adult world population has been infected with the oral pathogen, HSV-1. Approximately 30% of those infected with HSV-1 will have recurrences throughout their lifetime due to the fact that the virus establishes latency in sensory neurons that innervate the infected tissue. Reactivation occurs upon certain stimuli, such as ultraviolet light or psychological stress, which results in re-infection of tissue in the periphery. Because stress is a common and unavoidable process people experience on a daily basis, it is important to understand how stress impacts primary and recurrent HSV infection. Social disruption stress (SDR) has been shown to generate glucocorticoid-resistant monocytes/macrophages. Furthermore, SDR enhances the trafficking of glucocorticoid-resistant monocytes/macrophages from the bone marrow to the spleen, and increases pro-inflammatory cytokine production both in vitro and in vivo. In addition, SDR has also been shown to reliably reactivate HSV-1 in latently infected Balb/c mice. During an HSV-1 infection, mice exposed to SDR prior to a primary HSV infection had enhanced trafficking of monocytes/macrophages to the trigeminal ganglia 3 to 6 days p.i. This is likely due to increased protein levels of MCP-1 in SDR mice. In addition, the receptor for MCP-1, CCR2, was significantly increased on CD11b+ cells in SDR mice. Expression of CD11b was also increased in SDR mice compared to controls which corresponded with increase in the expression of its ligand, ICAM-1. Although gene expression of IFN-β was decreased, SDR increased gene expression of IFN-α and TNF-α in the cornea and TG. Examination of viral proteins showed decreased expression of ICP0, gB, gH and LAT in the TG, however, expression of ICP0 and gB were elevated in the cornea of SDR mice. Because there was a reduction in viral replication, it was likely that fewer neurons were latently infected thus diminishing the frequency and severity of future recurrences. Previous in vitro (open full item for complete abstract)

Committee: John Sheridan PhD (Advisor); Courtney DeVries PhD (Committee Member); John Hughes PhD (Committee Member); David Padgett PhD (Committee Member) Subjects: Dental Care; Immunology; Psychobiology; Psychology; Virology

Doctor of Philosophy, The Ohio State University, 2004, Medical Microbiology and Immunology

The immune system can be viewed as a diffuse sensory organ that is responsible for detecting and eliminating infiltrating pathogens. However, the immune system must strike a balance between limiting microbial replication and immune-induced pathology. The immune system has various regulatory mechanisms that can do this; one such immunoregulatory pathway is the bi-directional communication among the nervous, endocrine and immune system. Extrinsic factors, e.g. infection, and intrinsic factors, e.g. psychogenic stress, can activate the hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system (SNS). Activation of these systems by either stress or infection leads to the secretion of glucocorticoids (GCs), catecholamines and opioids. Chronic elevation of GCs by restraint (RST) stress modulated the immune response to an experimental influenza A/PR8 viral infection. As demonstrated by experiments contained herein, RST altered cytokine gene expression, suppressed NK cell activity, and attenuated lymphocyte trafficking. Finally, RST enhanced viral replication (probably as a consequence of the RST mediated immunomodulation). Thus, alteration of normal immunoregulatory mechanisms by RST modulated the inflammatory, innate and adaptive response to an influenza A/PR8 viral infection. Previous studies from our laboratory using a social stress paradigm, social disruption (SDR), showed that SDR induced a state of functional GC resistance in cultured splenocytes. SDR, depending on the timing of the infection relative to the SDR cycle, differentially affected immune response to an influenza viral infection. When SDR occurred concurrently with the influenza infection, cytokine gene expression in the lung was suppressed at early time points during the infection. However, cytokine gene expression returned to control levels after SDR was stopped. In contrast, SDR prior to the influenza challenge attenuated the infection-induced weight loss and corticosterone secretion. Furt (open full item for complete abstract)

Committee: John Sheridan (Advisor) Subjects: Health Sciences, Immunology

Doctor of Philosophy (PhD), Ohio University, 2007, Electrical Engineering & Computer Science (Engineering and Technology)

A transform-domain, instrumentation Global Positioning System (GPS) receiver is developed for high-fidelity signal quality monitoring (SQM), GPS anomalous event monitoring (GAEM), and GPS software-defined radio (SDR) research. Features of the receiver include: a radio frequency front-end with 24 MHz bandwidth on the GPS L1 (1575.42 MHz) and L2 (1227.6 MHz) frequencies with 14-bit sampling capability to capture and analyze high-dynamic-range signals such as in-band interference; An integrated GPS/Inertial Measurement Unit (IMU) data collection capability at 105 Mbytes/sec sustained transfer rate and 2-Terabyte capacity, with a novel, sub-microsecond resolution IMU time stamping method that significantly simplifies GPS/IMU deeply-integrated processing; a continuous-processing transform-domain engine that computes 1024-point complex parallel-code-correlation functions in less than 15 microseconds for 1-ms blocks of data; A runtime-configurable serial engine containing several hundred ‘split-sum' coarse/acquisition (C/A) code correlators operating on 14-bit input samples; A realtime transform-domain GPS receiver with full message decoding, range measurement, and position-velocity-time solution updates up to a 1 kHz rate. The receiver's graphical user interface allows runtime interaction via a set of software controls, and realtime internal-parameter graphing capabilities similar in function to a combined digital storage oscilloscope and spectrum analyzer. High-fidelity capabilities of the receiver include 55 points per C/A-chip SQM, and 10-correlator Precise-code SQM. The instrument's unique GPS/IMU interleaved data collection capability enabled a flight test where GPS carrier phase tracking was maintained for signals with carrier-to-noise ratios (CNR) at the 15 dB-Hz level. The receiver's application layer is built using a custom-developed, object-oriented applications programming interface that supports customization to suit a variety of applications. The instrument's (open full item for complete abstract)

Committee: Frank van Graas (Advisor) Subjects:

Master of Science in Electrical Engineering, Cleveland State University, 2010, Fenn College of Engineering

The aim of this thesis is to implement and test a real time wireless communication environment. Cooperative Communication is one of the methods by which a reliable communication can be obtained. This is performed using a Software Defined Radio. The received output is compared with the actual signal that is transmitted over the wireless channel. The wireless communications are often hindered by the noisy environments and make the system unreliable. The interference from neighboring nodes also poses a major disadvantage. There is a necessity to improve the performance of the system where the neighbor nodes can work in coordination with the sender. The intermediate nodes (also called as relay stations) cooperate in a distributed manner to prevent loss of bandwidth usage.

Committee: Chansu Yu PhD (Committee Chair); Fuqin Xiong PhD (Committee Member); Murad Hizlan (Committee Member) Subjects: Electrical Engineering

Master of Science, University of Akron, 2005, Electrical Engineering

The aim of this thesis is to design and implement a software defined radio based wireless communication system. Software defined radio is a feasible solution for reconfigurable radios, which can perform different functions at different times on the same hardware. The baseband section of a wireless communication system is first simulated and then implemented in hardware. The performance of the baseband transmitter is analyzed using constellation and eye diagrams for different modulation techniques and different signal-to-noise ratios, while considering an additive white Guassian noise channel. The performance of the receiver is analyzed by comparing the input and output waveforms. The performance of the system in real time is also analyzed by implementing the system in hardware using Xilinx Spartan 2E field programmable gate array. A comparison of the simulation results with the results obtained from implementing the system on Spartan 2E hardware is presented and discussed. It is shown that the simulation results and experimental results are similar.

Committee: Okechukwu Ugweje (Advisor) Subjects:

Doctor of Philosophy, The Ohio State University, 2013, Electrical and Computer Engineering

Until recently, the functionality of radar systems has been built into the radar's analog hardware, resulting in radars which are inflexible and that can only be used for a specific application. Modern systems, however, driven by the ever increasing speed of processors and data converters - analog-to-digital (ADC) and digital-to-analog (DAC) - are transitioning toward software defined radar (SDR) systems. The advent of SDRs inevitably leads to the question of how their added flexibilities can best be leveraged. The work within this dissertation is motivated by joint radar and communication functionality. The main objective is to study and demonstrate the ability of radar systems to employ non-traditional, specifically, communication waveforms for remote sensing. A software defined radar (SDR) is developed. The SDR features a "closed loop" testbed interface accessible via Matlab m-code. Here, "closed-loop" means that data can be pulled from the SDR, processed, then used to select/adapt the waveform and settings of the SDR without human intervention, i.e. on the fly. The testbed interface is used to implement a joint radar and communication system which is capable of collecting and processing radar data, e.g. range-Doppler maps, while simultaneously communicating previously collected radar data. Simultaneous functionality is accomplished by interrogating with a wide band digital communication waveform which is modulated with the previously collected radar data. The joint system is used to empirically demonstrate the theoretical work on detection and change detection within this dissertation. Optimal detectors are developed for interrogation with communication waveforms. The optimal detector for a single target with known impulse response in white noise is known to be a thresholding of the output of a matched filter. Radar systems, however, often operate in multi-target environments; notably air-to-ground synthetic aperture radars. For such applic (open full item for complete abstract)

Committee: Emre Ertin (Advisor); Randolph Moses (Advisor); Chris Baker (Committee Member) Subjects: Electrical Engineering