Assistance, channel, and networking models for A-GPS simulators, and extensions

dc.contributor.advisorAkopian, David
dc.contributor.authorHuang, Grant
dc.contributor.committeeMemberAgaian, Sos
dc.contributor.committeeMemberHuang, Yufei
dc.contributor.committeeMemberDe Oliveira, Victor
dc.descriptionThis item is available only to currently enrolled UTSA students, faculty or staff. To download, navigate to Log In in the top right-hand corner of this screen, then select Log in with my UTSA ID.
dc.description.abstractThe U.S. Global Positioning System (GPS) has an established reputation as a robust global technology allowing users to determine their locations using receivers incorporated in various devices including cell phones, PDAs, and watches. While GPS works well in open sky environments, location finding in weak-signal conditions, such as urban canyons and indoors, is challenging and has been the subject of extensive research. Assisted-GPS (A-GPS) is one of the concepts that help receivers acquire weaker signals by exploiting assistance data received from wireless networks, such as orbital parameters, and coarse time and location references. A-GPS is currently standardized technology in cellular communication since it evolved as a natural integration of GPS and wireless communication. Receiver technology developers work on more sensitive algorithms for enabling positioning in weak signal environments and typically rely on signal simulators for testing real-world scenarios. As the terrestrial assistance data channel becomes a foundational link for A-GPS, the statistical modeling of information delivery delays should be addressed for more adequate simulations as channel delays affect receiver operations. In particular, delays contribute to receiver response typically defined as a Time-to-First-Fix (TTFF). The main aspect of the dissertation is to study A-GPS channels by (a) developing a testbed for A-GPS simulation that includes a conventional GPS simulator integrated with an advanced channel model simulator and assistance data delivery over the Internet accessed through wireless links; (b) using the testbed to suggest channel delay measurement methodology; (c) conducting channel measurement campaigns and collecting representative data; and (d) proposing channel models that can be incorporated in A-GPS simulators for generating more realistic assistance communication scenarios for receiver testing. Different from conventional approaches, this dissertation promotes measurements of complete cycle delays including physical propagation and network delays due to data losses. It makes proposed methodology broader and applicable for other communication technologies. A case study of network channel delay modeling is conducted for Power Line Communications (PLC), which is also sensitive to delays in interactive applications (e.g. videoconferencing, remote control systems, online games). PLC emerged as a competitive technology for indoor broadband communications exploiting the existing power line infrastructure for data transmissions. The proposed network channel delay models are essentially based on testbeds for conducting measurement campaigns. The last aspect of the dissertation is the accessibility of testbed platforms for education, training, and resource sharing. Broader access to unique testbeds and experimentation labs in general is an essential component of engineering research, collaboration, and learning. However, high equipment and maintenance costs constrain experimentation infrastructure. Software simulators, based on mathematical models, address this problem to some extent, but interaction with real systems provides a richer and more authentic experience and is often the only available choice. This dissertation presents a recent initiative on designing a remote experimentation platform named eComLab for radio-communication enabling broader access. It addresses two goals: sharing testbeds for research needs and allowing practical educational lab offerings using limited equipment resources.
dc.description.departmentElectrical and Computer Engineering
dc.format.extent143 pages
dc.subjectNetwork delays
dc.subjectPower line communications
dc.subjectRemote experimentation platform
dc.subjectSecure user plane location
dc.subject.classificationElectrical engineering
dc.subject.lcshGlobal Positioning System
dc.subject.lcshWireless communication systems
dc.titleAssistance, channel, and networking models for A-GPS simulators, and extensions
dcterms.accessRightspq_closed and Computer Engineering of Texas at San Antonio of Philosophy


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