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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A Study into the Tradeoffs Between TDM / MF-SCPC and TDM / MF-TDMA Transport Options to Support IP-Based Multimedia Applications Under Different Load Conditions Within a Point-to-Multipoint Satellite Network

Good, Stephen D. 05 June 2012 (has links)
This thesis provides the reader with an overview of the many elements that are involved in geosynchronous satellite point-to-multipoint Internet Protocol (IP)-based multimedia communications design and also takes a deep dive into the analysis of a real-life scenario, using the TDM / MF-SCPC and TDM / MF-TDMA media access techniques. This thesis starts with a discussion of satellite network topologies utilized within point-to-multipoint satellite communications followed by an overview of the satellite communications channel. A discussion on the intelligent and proper selection of modulation and coding follows. Descriptions and characteristics of the satellite access technologies chosen to be analyzed are next followed by a detailed description of Forward Error Correction (FEC) techniques and a discussion on network-wide tradeoffs so selecting different options. The thesis then presents the results of a real-life scenario, investigating both TDM / MF-SCPC and TDM / MF-TDMA media access technique options, pointing out the tradeoffs brought to the forefront earlier in the study. The major takeaway is that there does not exist a one-size-fits-all solution that works for each and every scenario. / Master of Science
2

Reliable RFID Communication and Positioning System for Industrial IoT

Zhai, Chuanying January 2016 (has links)
The Internet of Things (IoT) has the vision to interconnect everything of the physical world and the virtual world. Advanced automated and adaptive connectivity of objects, systems, and services is expected to be achieved under the IoT context, especially in the industrial environment. Industry 4.0 with the goal of intelligent and self-adaptable manufacturing is driven by the IoT. The Object Layer, where real-time and reliable information acquisition from the physical objects carried out, is the basic enabler in the 3-layer industrial IoT system. Such acquisition system features deterministic access, reliable communication with failure resistance mechanism, latency-aware real-time response, deployable structure/protocol, and adaptive performance on various QoS demands. This thesis proposes a reliable RFID communication system for acquisition in the industrial environment. A discrete gateway structure and a contention-free communication protocol are designed to fulfill the unique system requirements. Such gateway structure offers a flexible configuration of readers and RF technologies. It enables a full duplex communication between the objects and the gateway. The designed MF-TDMA protocol can enhance the failure resistance and emergency report mechanism thanks to the separation of control link and data link in the gateway. Specifically, an optional ARQ mechanism, an independent/uniform synchronization and control method, and a slot allocation optimization algorithm are designed besides time-division and frequency-division multiplexing. Protocol implementations for different industrial situations illustrate the system ability for supporting the demands of various QoS. Finally, a 2.4-GHz/UWB hybrid positioning platform is explored based on the introduced RFID system. Taking advantage of the UWB technology, the positioning platform can achieve positioning accuracy from meter level to centimeter level. Hybrid tag prototype and specific communication process based on the MF-TDMA protocol are designed. An SDR UWB reader network, capable of evaluating multiple algorithms, is built to realize accurate positioning with an improved algorithm proposed. / <p>QC 20161109</p>

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