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Title: Secure and efficient spectrum sharing and QoS analysis in OFDM-based heterogeneous wireless networks
Creator: Alahmadi, Ahmed S.
Date: 2016
Collection: Electronic Theses & Dissertations
Description: "The Internet of Things (IoT), which networks versatile devices for information exchange, remote sensing, monitoring and control, is finding promising applications in nearly every field. However, due to its high density and enormous spectrum requirement, the practical development of IoT technology seems to be not available until the release of the large millimeter wave (mmWave) band (30GHz-300GHz). Compared to existing lower band systems (such as 3G, 4G), mmWave band signals generally require...
Show more"The Internet of Things (IoT), which networks versatile devices for information exchange, remote sensing, monitoring and control, is finding promising applications in nearly every field. However, due to its high density and enormous spectrum requirement, the practical development of IoT technology seems to be not available until the release of the large millimeter wave (mmWave) band (30GHz-300GHz). Compared to existing lower band systems (such as 3G, 4G), mmWave band signals generally require line of sight (LOS) path and suffer from severe fading effects, leading to much smaller coverage area. For network design and management, this implies that: (i) MmWave band alone could not support the IoT networks, but has to be integrated with the existing lower band systems through secure and effective spectrum sharing, especially in the lower frequency bands; and (ii) The IoT networks will have very high density node distribution, which is a significant challenge in network design, especially with the scarce energy budget of IoT applications. Motivated by these observations, in this dissertation, we consider three problems: (1) How to achieve secure and effective spectrum sharing? (2) How to accommodate the energy limited IoT devices? (3) How to evaluate the Quality of Service (QoS) in the high density IoT networks? We aim to develop innovative techniques for the design, evaluation and management of future IoT networks under both benign and hostile environments. The main contributions of this dissertation are outlined as follows. First, we develop a secure and efficient spectrum sharing scheme in single-carrier wireless networks. Cognitive radio (CR) is a key enabling technology for spectrum sharing, where the unoccupied spectrum is identified for secondary users (SUs), without interfering with the primary user (PU). A serious security threat to the CR networks is referred to as primary user emulation attack (PUEA), in which a malicious user (MU) emulates the signal characteristics of the PU, thereby causing the SUs to erroneously identify the attacker as the PU. Here, we consider full-band PUEA detection and propose a reliable AES-assisted DTV scheme, where an AES-encrypted reference signal is generated at the DTV transmitter and used as the sync bits of the DTV data frames. For PU detection, we investigate the cross-correlation between the received sequence and reference sequence. The MU detection can be performed by investigating the auto-correlation of the received sequence. We further develop a secure and efficient spectrum sharing scheme in multi-carrier wireless networks. We consider sub-band malicious user detection and propose a secure AES-based DTV scheme, where the existing reference sequence used to generate the pilot symbols in the DVB-T2 frames is encrypted using the AES algorithm. The resulted sequence is exploited for accurate detection of the authorized PU and the MU. Second, we develop an energy efficient transmission scheme in CR networks using energy harvesting. We propose a transmitting scheme for the SUs such that each SU can perform information reception and energy harvesting simultaneously. We perform sum-rate optimization for the SUs under PUEA. It is observed that the sum-rate of the SU network can be improved significantly with the energy harvesting technique. Potentially, the proposed scheme can be applied directly to the energy-constrained IoT networks. Finally, we investigate QoS performance analysis methodologies, which can provide insightful feedbacks to IoT network design and planning. Taking the spatial randomness of the IoT network into consideration, we investigate coverage probability (CP) and blocking probability (BP) in relay-assisted OFDMA networks using stochastic geometry. More specifically, we model the inter-cell interference from the neighboring cells at each typical node, and derive the CP in the downlink transmissions. Based on their data rate requirements, we classify the incoming users into different classes, and calculate the BP using the multi-dimensional loss model."--Pages ii-iii.
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Title: Building a location-based prioritized overlay multicast in ad-hoc environments
Creator: Liu, Yunhao
Date: 2003
Collection: Electronic Theses & Dissertations

Title: On SNR aware analysis and modeling of 802.11b link-level residual errors
Creator: Prabhu Parrikar, Utpal M.
Date: 2006
Collection: Electronic Theses & Dissertations

Title: Improving data transmission reliability and throughput in wireless sensor networks
Creator: Lee, Ee Foong
Date: 2008
Collection: Electronic Theses & Dissertations

Title: A framework for handling user mobility in wireless ATM networks
Creator: Lin, Hui-Tang
Date: 1998
Collection: Electronic Theses & Dissertations

Title: Welfare impacts of spectrum governance regimes : an economic-engineering study
Creator: Ting, Yi-Feng Carol
Date: 2005
Collection: Electronic Theses & Dissertations

Title: Coding over resource-constrained wireless networks
Creator: Halloush, Rami D.
Date: 2012
Collection: Electronic Theses & Dissertations
Description: In practice, wireless networks operate under multiple, mostly severe, constraints (bandwidth, energy resources, etc). Consequently, efficient techniques have to be employed in communicating data with sufficiently high data rates (depending on the application) while complying with the imposed constraints. Distributed Video Coding (DVC) and Network Coding (NC) are amongst the most dominant techniques employed in constrained data networks. In this dissertation, we address these two techniques...
Show moreIn practice, wireless networks operate under multiple, mostly severe, constraints (bandwidth, energy resources, etc). Consequently, efficient techniques have to be employed in communicating data with sufficiently high data rates (depending on the application) while complying with the imposed constraints. Distributed Video Coding (DVC) and Network Coding (NC) are amongst the most dominant techniques employed in constrained data networks. In this dissertation, we address these two techniques with the objective of realizing practical and efficient data networking solutions that fit in resource constrained wireless networks. In one part of the dissertation we address DVC over Visual Sensor Networks (VSNs) from a practical point of view, i.e., unlike a large body of research work related to this topic where the focus is on theoretical analysis and simulation, we study the practical aspects that arise when deploying DVC over real visual sensors. To that end, we develop a Resource-constrained DVC (RDVC) codec, deploy it over some of the widely used visual sensors, and conduct precise energy measurements that are used throughout our study.One RDVC-related challenge that we address in this dissertation is source rate estimation, i.e., trying to efficiently identify the source rate to be used in encoding a frame. This question is crucial since sending more bits than necessary will lead to inefficiency in compression while sending fewer bits will lead to failure in decoding. We propose a practical solution that completely eliminates the need for the costly feedback messages.Another challenge we address is the global choice between a DVC encoding option that involves intensive computations and leads to less transmission versus another choice with minimal computations that implies higher transmission-energy overhead. We carry out an operational energy-distortion analysis for a variety of options available to RDVC on visual sensors.Polar codes are the first codes proven to achieve capacity while having low encoding and decoding complexity. This motivates us to employ polar codes in our DVC platform. We compare the performance of polar codes with the more established and more investigated Low Density Parity Check Accumulate (LDPCA) codes in the context of DVC. Our results show that polar codes offer a clear advantage when coding smaller size image blocks. Consequently, polar codes could represent a viable solution for distributed sensor networks that capture low-resolution video signals. In the final part of the dissertation, we survey state-of-the-art NC solutions designed to achieve high throughput transmission in multicasting over wireless mesh networks while maintaining 100% packet delivery ratio. We propose HopCaster; a scheme that employs the cache-and-forward transport strategy. We show that HopCaster achieves significant performance gains compared to schemes that employ the end-to-end transport strategy.
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Title: The uses of cellular telephony in Taiwan
Creator: Hsu, Hsiu-Yueh
Date: 1992
Collection: Electronic Theses & Dissertations

Title: Tackling the challenges of wireless interference and coexistence
Creator: Huang, Jun
Date: 2012
Collection: Electronic Theses & Dissertations
Description: Recent years have witnessed the phenomenal penetration rate of wireless networks in our daily lives, ranging from 802.11-based wireless LANs that provide ubiquitous Internet access, to 802.15.4-based wireless sensor networks that carry out various mission-critical tasks such as security surveillance and patient monitoring. However, despite the advances in the field of wireless networking, how to design high-performance wireless networks remains an open problem because of the fundamental...
Show moreRecent years have witnessed the phenomenal penetration rate of wireless networks in our daily lives, ranging from 802.11-based wireless LANs that provide ubiquitous Internet access, to 802.15.4-based wireless sensor networks that carry out various mission-critical tasks such as security surveillance and patient monitoring. However, despite the advances in the field of wireless networking, how to design high-performance wireless networks remains an open problem because of the fundamental challenges of wireless interference and coexistence.Interference is the fundamental factor that limits the link concurrency of wireless networks. Due to the broadcast nature of wireless channel, concurrent transmissions on the same frequency interfere with each other over the air, resulting in lower throughput and higher delivery delay. Handling interference in wireless networks is difficult because of the hidden terminal problem and the exposed terminal problem. Although the former is well studied in existing literature, the later is not, especially in networks where multiple bit rates are available.Another challenge is that interference significantly hinders the coexistence of different wireless technologies. In particular, recent studies show that wireless coexistence is becoming a growing issue due to the unprecedented proliferation of wireless devices in the unlicensed 2.4GHz band. When devices of heterogeneous physical layer operating on the same frequency, interference is more difficult to resolve as devices cannot decode the signals of each other. Moreover, co-existing devices commonly transmit at different powers, which leads to unfair channel usage. The issue is particularly critical to lower power wireless devices. This thesis tackles the fundamental challenges of wireless interference and coexistence to the link layer design of wireless networks. In particular, we identify two problems in the design of existing link layer protocols, and advance the state-of-the-art by offering practical solutions: (1) the rate-adaptive exposed terminal problem where link concurrency cannot be fully exploited by conventional link layers because of they are oblivious to the bit rate diversity; and (2) the blind terminal problem where existing link layer protocols fail to work in co-existing environments due to the heterogeneous physical layer and power asymmetry of co-existing devices. We motivate this research by showing that existing link layer protocols are surprisingly ineffective in handling these problems. Our experiments pinpoint the fundamental reasons of such ineffectiveness and reveal their implications on the design of link layer protocols. We then develop practical solutions to tackle the identified problems. Extensive testbed-based experiments validate the design of proposed solutions, and demonstrate their significant performance gains over existing link layer protocols.
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Title: Autoconfiguration and security for wireless networks
Creator: Zhou, Hongbo
Date: 2005
Collection: Electronic Theses & Dissertations

Title: Advanced approaches in information transmission and access control for wireless communication networks
Creator: Wang, Huahui
Date: 2006
Collection: Electronic Theses & Dissertations

Title: Cooperative content caching for capacity and cost management in mobile ecosystems
Creator: Taghi Zadeh Mehrjardi, Mahmoud
Date: 2012
Collection: Electronic Theses & Dissertations
Description: The objective of this thesis is to develop an architectural framework of social community based cooperative caching for minimizing electronic content provisioning cost in Mobile Social Wireless Networks (MSWNET). MSWNETs are formed by wireless mobile devices sharing common interests in electronic content, and physically gathering in public settings such as University campuses, work places, malls, and airports. Cooperative caching in such MSWNETs are shown to be able to reduce content...
Show moreThe objective of this thesis is to develop an architectural framework of social community based cooperative caching for minimizing electronic content provisioning cost in Mobile Social Wireless Networks (MSWNET). MSWNETs are formed by wireless mobile devices sharing common interests in electronic content, and physically gathering in public settings such as University campuses, work places, malls, and airports. Cooperative caching in such MSWNETs are shown to be able to reduce content provisioning cost which heavily depends on service and pricing dependencies among various stakeholders including content providers, network service providers, and end consumers. This thesis develops practical network, service, and economic pricing models which are then used for creating an optimal cooperative caching strategy based on social community abstraction in wireless networks. The developed framework includes optimal caching algorithms, analytical models, simulation, and prototype experiments for evaluating performance of the proposed strategy. The main contributions are: 1) formulation of economic cost-reward flow models among the MSWNET stakeholders, 2) developing optimal distributed cooperative caching algorithms, 3) characterizing the impacts of network, user and object dynamics, 4) investigating the impacts of user non-cooperation, and finally 5) developing a prototype Social Wireless Network for evaluating the impacts of cooperative caching in a Mobile Social Wireless Networks.
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Title: A wirelessly controlled magnetic force actuator and its AFM measurements
Creator: Abu-Nimeh, Faisal T.
Date: 2007
Collection: Electronic Theses & Dissertations

Title: Supporting real-time and multimedia applications in wireless networks
Creator: Du, Fan
Date: 2001
Collection: Electronic Theses & Dissertations

Title: A network feedback architecture for self adaptive applications in wireless networks
Creator: Singh, Nagendra S.
Date: 2004
Collection: Electronic Theses & Dissertations

Title: CMOS variable gain amplifier (VGA) for application in RF front end of a satellite tv tuner
Creator: Rosik, Nick Joel
Date: 2004
Collection: Electronic Theses & Dissertations

Title: Complexity distortion optimization for video over wireless devices
Creator: Ray, Alan Paul
Date: 2004
Collection: Electronic Theses & Dissertations

Title: BTAudio (Bluetooth Audio Program) and quite talk profile
Creator: Chen, Jun
Date: 2003
Collection: Electronic Theses & Dissertations

Title: Flexible spectrum use in channel bonding wireless networks
Creator: Yang, Xi (Software engineer)
Date: 2014
Collection: Electronic Theses & Dissertations
Description: Channel bonding, which assembles multiple narrow channels into one logical channel, can speed up data transmission and achieve better bandwidth utilization in wireless networks. Since introduced in 802.11n, channel bonding has been extended continually to support wider channels, making low-lag high-speed wireless communication possible. However, different radio technologies have different requirements on channel width. Devices that use different channel widths coexist in a contention domain...
Show moreChannel bonding, which assembles multiple narrow channels into one logical channel, can speed up data transmission and achieve better bandwidth utilization in wireless networks. Since introduced in 802.11n, channel bonding has been extended continually to support wider channels, making low-lag high-speed wireless communication possible. However, different radio technologies have different requirements on channel width. Devices that use different channel widths coexist in a contention domain may cause inefficiency and unfairness issues. For example, narrowband devices are easier to obtain medium access opportunities because they do not need to wait for the entire wide band to be idle. Therefore, although wideband devices can provide higher transmission speed, they are at an unfavorable position in contentions with narrowband devices.To this end, we propose a flexible spectrum use channel bonding (FSUB) protocol in which a node is allowed to start a transmission whenever there are some idle narrow channels and gradually increases the channel width during transmission. Because a node dynamically adjusts the channel width in a communication, we use a convolution method to achieve fast spectrum agreement between the transmitter and the receiver. To address contentions between devices in a wide band of spectrum, we introduce a compound preamble to make the collisions detectable in the frequency domain and use a parallel bitwise arbitration mechanism to quickly determine the winner. We implement and evaluate the proposed protocol through both the GNU Radio/USRP platform and ns-2 simulations. The results show that the proposed protocol well addresses the inefficiency and unfairness issues caused by heterogeneous radio coexistence. Channel bonding devices usingFSUB have more medium access opportunities and can aggregate wider channels than using other channel bonding protocols in presence of narrowband interference. The FSUB enables a device to always benefit from channel bonding without concerns about narrowband interference level.
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Title: Analysis and design of reliable and stable link-layer protocols for wireless communication
Creator: Soltani, Sohraab
Date: 2009
Collection: Electronic Theses & Dissertations

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