Computer Engineering Commons^™

Domain Aware Deep Learning For Wireless Physical Layer, Shuvam Chakraborty

Legacy Theses & Dissertations (2009 - 2024)

Wireless receiver design for OFDM systems is well investigated with classical signal processing tools, which lack the capacity to extract intrinsic channel effects in received signal and lead to high decoding error in receiver. Current deep learning techniques have shown improvement in such cases. But these models are mostly being developed as black box without any anchor to the theory of wireless signal propagation, which leads to surface level information gain and lacks generalizability. We propose deep learning models where the hyperparameters and learning objectives are derived from domain knowledge of wireless signal propagation. These models not only increase the …

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 …

Mixed Carrier Communication For Sixth-Generation Networks :, Ahmed Fahmy Mahmoud Hussein

Legacy Theses & Dissertations (2009 - 2024)

Recently, research on sixth-generation (6G) wireless networks has gained significant interest. By 2030, it is expected that 6G will introduce revolutionary applications and services. Thus, 6G is likely to expand across all available spectrum, including terahertz (THz) and optical frequency bands. Although 5G will offer a massive upgrade to the spectrum, the technology does not provide solutions to support a vast multitude of services and devices simultaneously.Motivated by the heterogeneity of wireless technologies, devices, and services, the Mixed Carrier Communication (MCC) concept is introduced for the first time. MCC is a novel concept that supports the 6G vision by enabling …

Communications Using Deep Learning Techniques, Priti Gopal Pachpande

Legacy Theses & Dissertations (2009 - 2024)

Deep learning (DL) techniques have the potential of making communication systems

Autonomous Spectrum Enforcement : A Blockchain Approach, Maqsood Ahamed Abdul Careem

Legacy Theses & Dissertations (2009 - 2024)

A core limitation in existing wireless technologies is the scarcity of spectrum, to support the exponential increase in Internet-connected and multimedia-capable mobile devices and the increasing demand for bandwidth-intensive services. As a solution, Dynamic Spectrum Access policies are being ratified to promote spectrum sharing for various spectrum bands and to improve the spectrum utilization. This poses an equally challenging problem of enforcing these spectrum policies. The distributed and dynamic nature of policy violations necessitates the use of autonomous agents to implement efficient and agile enforcement systems. The design of such a fully autonomous enforcement system is complicated due to the …

Passive Synthetic Aperture Radar Imaging Using Commercial Ofdm Communication Networks, Jose R. Gutierrez Del Arroyo

Theses and Dissertations

Modern communication systems provide myriad opportunities for passive radar applications. OFDM is a popular waveform used widely in wireless communication networks today. Understanding the structure of these networks becomes critical in future passive radar systems design and concept development. This research develops collection and signal processing models to produce passive SAR ground images using OFDM communication networks. The OFDM-based WiMAX network is selected as a relevant example and is evaluated as a viable source for radar ground imaging. The monostatic and bistatic phase history models for OFDM are derived and validated with experimental single dimensional data. An airborne passive collection …

Mobile Map Browsers: Anticipated User Interaction For Data Pre-Fetching, Benjamin T. Weber

Electronic Theses and Dissertations

When browsing a graphical display of geospatial data on mobile devices, users typically change the displayed maps by panning, zooming in and out, or rotating the device. Limited storage space on mobile devices and slow wireless communications, however, impede the performance of these operations. To overcome the bottleneck that all map data to be displayed on the mobile device need to be downloaded on demand, this thesis investigates how anticipated user interactions affect intelligent pre-fetching so that an on-demand download session is extended incrementally. User interaction is defined as a set of map operations that each have corresponding effects on …

Dialable Cryptography For Wireless Networks, Marnita T. Eaddie

Theses and Dissertations

The objective of this research is to develop an adaptive cryptographic protocol, which allows users to select an optimal cryptographic strength and algorithm based upon the hardware and bandwidth available and allows users to reason about the level of security versus the system throughput. In this constantly technically-improving society, the ability to communicate via wireless technology provides an avenue for delivering information at anytime nearly anywhere. Sensitive or classified information can be transferred wirelessly across unsecured channels by using cryptographic algorithms. The research presented will focus on dynamically selecting optimal cryptographic algorithms and cryptographic strengths based upon the hardware and …

Priority Based Buffering Over Multiple Lossy Links Using Tcp Aware Layer Buffering, Kevin J. Savidge

Theses and Dissertations

Wireless military information systems require high reliability, which is difficult to achieve in adverse conditions. To provide high reliability, one must overcome packet loss across multiple wireless hops. Buffering packets in a lossy environment is well explored; however, the ability to selectively buffer TCP traffic across multiple lossy links is a new area of research. This document seeks to explore the delivery of high priority traffic in a lossy environment and conclude that prioritized buffing can increase the probability that a high priority download will finish, where others will fail. It is shown that buffering provides six times the throughput …

Scripted Mobile Network Routing In A Contested Environment, Anthony R. Otto

Theses and Dissertations

Mobile wireless network protocols currently run on optimistic routing algorithms, adjusting node connectivity only when the chosen connectivity metrics, such as signal strength, pass beyond minimum thresholds. Optimistic routing has several weaknesses. Optimistic routing suffers from increased network overhead during increased frequency of node movement and increased node density per area, and optimistic routing also suffers from non-optimistic access change for individual nodes. The overall communication throughput of a network may be increased if the network topology change is scripted; a scripted plan can allow messages to travel along a more efficient topological path while creating less topology control traffic. …

Performance Analysis And Comparison Of Multiple Routing Protocols In A Large-Area, High Speed Mobile Node Ad Hoc Network, Daniel K. Roberts

Theses and Dissertations

The U.S. Air Force is interested in developing a standard ad hoc framework using "heavy" aircraft to route data across large regions. The Zone Routing Protocol (ZRP) has the potential to provide seamless large-scale routing for DOD under the Joint Tactical Radio System program. The goal of this study is to determine if there is a difference between routing protocol performance when operating in a large-area MANET with high-speed mobile nodes. This study analyzes MANET performance when using reactive, proactive, and hybrid routing protocols, specifically AODV, DYMO, Fisheye, and ZRP. This analysis compares the performance of the four routing protocols …

On-Demand Key Distribution For Mobile Ad-Hoc Networks, Daniel F. Graham

Theses and Dissertations

Mobile ad-hoc networks offer dynamic portable communication with little or no infrastructure. While this has many benefits, there are additional shortcomings specific to wireless communication that must be addressed. This research proposes gossip-based on-demand key distribution as a means to provide data encryption for mobile ad-hoc networks. This technique uses message keys to avoid encrypting and decrypting a message at every node. Other optimizations used include secure channel caching and joint rekey messages. The use of gossip makes the scheme robust to node failure. Experimental results show only a 15% increase in end-to-end delay with a node failure rate of …

Overcoming Tcp Degradation In The Presence Of Multiple Intermittent Link Failures Utilizing Intermediate Buffering, Duane F. Harmon

Theses and Dissertations

It is well documented that assumptions made in the popular Transmission Control Protocol's (TCP) development, while essential in the highly reliable wired environment, are incompatible with today's wireless network realities in what we refer to as a challenged environment. Challenged environments severely degrade the capability of TCP to establish and maintain a communication connection with reasonable throughput. This thesis proposes and implements an intermediate buffering scheme, implemented at the transport layer, which serves as a TCP helper protocol for use in network routing equipment to overcome short and bursty, but regular, link failures. Moreover, the implementation requires no modifications to …

Evaluation Of Energy Costs And Error Performance Of Range-Aware Anchor-Free Localization Algorithms For Wireless Sensor Networks, Gustav Julio Jordt

Theses and Dissertations

This research examines energy and error tradeoffs in Anchor-Free Range-Aware Wireless Sensor Network (WSN) Localization algorithms. A concurrent and an incremental algorithm (Anchor Free Localization (AFL) and Map Growing) are examined under varying network sizes, densities, deployments, and range errors. Despite current expectations, even the most expensive configurations do not expend significant battery life (at most 0.4%), implying little energy can be conserved during localization. Due to refinement, AFL is twice as accurate, using 6 times the communication. For both, node degree affects communication most. As degree increases, Map Growing communication increases, while AFL transmissions drop. Nodes with more neighbors …

Supplementing An Ad-Hoc Wireless Network Routing Protocol With Radio Frequency Identification (Rfid) Tags, Leroy S. Willemsen

Theses and Dissertations

Wireless sensor networks (WSNs) have a broad and varied range of applications, yet all of these are limited by the resources available to the sensor nodes that make up the WSN. The most significant resource is energy. A WSN may be deployed to an inhospitable or unreachable area, leaving it with a non-replenishable power source. This research examines a way of reducing energy consumption by augmenting the nodes with radio frequency identification (RFID) tags that contain routing information. It was expected that RFID tags would reduce the network throughput, the ad hoc on-demand distance vector (AODV) routing traffic sent, and …

An Adaptable Energy-Efficient Medium Access Control Protocol For Wireless Sensor Networks, Justin T. Kautz

Theses and Dissertations

Wireless networks have become ubiquitous recently and therefore their usefulness has also become more extensive. Wireless sensor networks (WSN) detect environmental information with sensors in remote settings. One problem facing WSNs is the inability to resupply power to these energy-constrained devices due to their remoteness. Therefore to extend a WSN's effectiveness, the lifetime of the network must be increased by making them as energy efficient as possible. An energy efficient medium access control (MAC) can boost a WSN's lifetime. This research creates a MAC protocol called Adaptive sensor Medium Access Control (AMAC) which is based on Sensor Medium Access Control …

Analysis Of Relay-Based Cellular Systems, Ansuya Negi

Dissertations and Theses

Relays can be used in cellular systems to increase coverage as well as reduce the total power consumed by mobiles in a cell. This latter benefit is particularly useful for mobiles operating on a depleted battery. The relay can be a mobile, a car or any other device with the appropriate communication capabilities. In thesis we analyze the impact of using relays under different situations. We first consider the problem of reducing total power consumed in the system by employing relays intelligently. We find that in a simulated, fully random, mobile cellular network for CDMA (Code Division Multiple Access), significant …

Free Roaming: A System For Ubiquitous Computing, Huanjin Liu

Theses Digitization Project

Based on the Umbilical Cord system, this project enriches the Ubiquitous Computing system with a Free Roaming system. This Free Roaming consists of a distributed authentication system, a data caching system and a communication system between them. It allows user to roam within this system and access his data everywhere. Together with the Umbilical Cord system, a Ubiquitous Computing system is functionally completed as a prototype, and is ready to be deployed into the Internet.

Device Discovery In Frequency Hopping Wireless Ad Hoc Networks, Brian S. Peterson

Theses and Dissertations

This research develops a method for efficient discovery of wireless devices for a frequency hopping spread spectrum, synchronous, ad hoc network comprised of clustered sub-networks. The Bluetooth wireless protocol serves as the reference protocol. The development of a discovery, or outreach, method for scatternets requires the characterization of performance metrics of Bluetooth piconets, many of which are unavailable in literature. Precise analytical models characterizing the interference caused to Bluetooth network traffic by inquiring devices, the probability mass function of packet error rates between arbitrary pairs of Bluetooth networks, and Bluetooth discovery time distribution are developed. Based on the characterized performance …

Address Assignment In Ad-Hoc Networks, John Paul O'Grady

Theses

A wireless ad-hoc network is a collection of autonomous nodes or terminals that communicate with each other by forming a multi-hop radio network and maintaining connectivity in a decentralised manner. In an ad hoc network routing is used to find and maintain a path through the network. Routing requires each node to have a unique identifier, to ensure that packets sent to a particular node reach their intended destination. Most ad-hoc routing protocols assume that a node already has an address prior to its entry into a network and so the issue of address assignment is largely ignored. This however …

Performance Estimation Of A Sip Based Push-To-Talk Service For 3g Wireless Networks, Eoin O'Regan

Theses

Push To Talk (PTT) services have been in existence for several decades providing dispatch services via two-way radio such as walkie-talkies. For a number of years now PTT services have been available for use over mobile phone networks. These mobile PTT services have occupied a niche market with business users and have been provided on proprietary networks that do not enable roaming.

Over the past year there has been an explosion of interest in the concept of PTT provided over mobile networks using Internet Protocol (IP) technology. This service uses cellular access and radio resources more efficiently than circuit-switched cellular …

Wlan Csma/Ca Performance In A Bluetooth Interference Environment, Randall B. Noel

Theses and Dissertations

IEEE 802.11 WLANs and Bluetooth piconets both operate in the 2.4 GHz Industrial Scientific and Medical (ISM) radio band. When operating in close proximity, these two technologies interfere with each other. Current literature suggests that IEEE 802.11 (employing direct sequence spread spectrum technology) is more susceptible to this interference than Bluetooth, which uses frequency hopping spread spectrum technology, resulting in reduced throughput. Current research tends to focus on the issue of packet collisions, and not the fact that IEEE 802.11 may also delay its transmissions while the radio channel is occupied by a Bluetooth signal. This research characterizes previously neglected …

Wireless Local Area Network Security : An Investigation Into Security Tool Usage In Wireless Networks, Susan Webb

Theses : Honours

Many organisations and individuals installing wireless local area networks (WLANs), which are based on the IEEE 802.11 b standard, have little understanding of the security issues that surround this technology.

This study was initiated to determine how WLAN security issues affect organisations in Perth, Western Australia. The scope of the study was restricted to 802.llb WLANs operating in infrastructure mode, where all traffic is transmitted by wireless access points (APs). This study was conducted in two phases. The general aims of the first phase were to determine the number of detectable WLANs in the Perth Central Business District (CBD) and …

Mobile Used Car Prices And Information, Ting-Shiuan Chang

Theses Digitization Project

Wireless is getting more important and popular because its convenience and portability make things easier. The goal of this project is to develop a mobile vehicle application called MOBILE USED CAR PRICES AND INFORMATION and this application will provide the prices and information for clients. The client can use their Palm handheld devices to read the prices and information whenever they want to check.

Performance Evaluation Of Hyperbolic Position Location Technique In Cellular Wireless Networks, Hakan Senturk

Theses and Dissertations

This study addresses the wireless geolocation problem that has been an attractive subject for the last few years after Federal Communications Commission (FCC) mandate for wireless service providers to locate emergency 911 users with a high degree of accuracy -within a radius of 125 meters, 67 percent of the time by October 2001. There are a number of different geolocation technologies that have been proposed. These include, Assisted GPS (A-GPS), network-based technologies such as Enhanced Observed Time Difference (E-OTD), Time Difference of Arrival (TDOA), Angle of Arrival (AOA), and Cell of Origin (COO). This research focuses on network based techniques, …

Integrated Manet Mutual Authentication System, Jason T. Ballah

Theses and Dissertations

The Integrated MANET Mutual Authentication System (IMMAS) provides implied mutual authentication of all routing and data traffic within a Mobile Ad Hoc Network (MANET) by combining Elliptic Curve Cryptography, a public-key cryptosystem, with the Dynamic Source Routing (DSR) Protocol. IMMAS provides security by effectively hiding network topology from adversaries while reducing the potential for, among other things, traffic analysis and data tampering, all while providing a graceful degradation for each of the authentication components. Current research in MANETs tends to focus primarily on routing issues leaving topics such as security and authentication for future research. IMMAS focuses on achieving a …

Factors Affecting The Bit Error Rate Performance Of The Indoor Radio Propagation Channel For 2.3-2.5 Ghz Frequency Band, Edward A. Walker

Theses: Doctorates and Masters

The use of wireless in buildings based on microwave radio technology has recently become a viable alternative to the traditional wired transmission media. Because of the portable nature of radio transceivers, the need for extensive cabling of buildings with either twisted pair, coaxial, or optical fibre cable is eliminated. This is particularly desirable where high user mobility occurs and existing wiring is not in place, or buildings are heritage in nature and extensive cabling is seen as intrusive. Economic analysis bas also shown that significant labour cost savings can result by using a radio system or a hybrid mix of …

Mobile Order Entry System Based On The Wireless Technology, Sumit Imsuksri

Theses Digitization Project

The sales representatives primary duties are to attract wholesale and retail buyers and purchasing agents to their merchandise, and to address any of their client's questions or concerns. Aided by a laptop computer connected to the Internet, they can access the customer information and sell products to their customer immediately. This project, a Mobile Order Entry System using cellphones, will give sales representatives as state-of-the-art alternative in accessing anf selling products to their customers through cell phones instead of using laptop computers.

Wireless Messaging And Project Management System, Bhrigu Celly

Theses Digitization Project

Wireless is an important part of the future and utilizing the wireless technology in project management is a great tool. This project is a messaging system designed using WAP and Java Server pages, as both of them are the technologies of the future. The project puts together a tool to help in project management made with the use of Java Server Pages and MySQL as the backend database. It uses Wireless Markup Language as the basic language for the cellular phones and the hand held wireless devices. The prototype has been modeled on project planning for power plants done by …

Using Direct-Sequenced Spread Spectrum In A Wired Local Area Network, Robert J. Bonner

Theses and Dissertations

Code division multiple access provides an ability to share channel bandwidth amongst users at the same time. Individual user performance is not degraded with the addition of more users, unlike traditional Ethernet. Using direct sequenced spread spectrum in a wired local area network, network performance is improved. For a network in overload conditions, individual station throughput is increased by nearly 212% while mean end-to-end delay was reduced by 800%. The vast improvement demonstrated by this research has the capability to extend legacy-cabling infrastructures for many years to come while easily accommodating new bandwidth intensive multimedia applications.