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dc.contributor.authorBaldassaro, Paige Marieen_US
dc.date.accessioned2014-03-14T20:44:05Z
dc.date.available2014-03-14T20:44:05Z
dc.date.issued2001-08-15en_US
dc.identifier.otheretd-08242001-132339en_US
dc.identifier.urihttp://hdl.handle.net/10919/34724
dc.description.abstractThis thesis presents a model to predict signal strength for frequencies between 902 MHz and 28 GHz. The model approximates diffraction using the knife-edge concept and equations proposed by Lee (1985). LOS pathways are calculated using the Bresenham algorithm and the corresponding elevations are obtained from a 30m DEM base map. The base map was generated by the procedure outlined in Rose (2001) and includes building elevations. The effect of Fresnel zones on prediction accuracy is considered. The effect of interpolating elevations along the Bresenham line is also considered. An Inverse Distance Weighting algorithm was used to interpolate the elevations. The accuracy of the model was evaluated using received signal strength data compiled from studies conducted at 902 MHz, 24.12 GHz and 27.525 GHz. In addition to the compiled data, data was also collected for this study at 2.4 GHz. 257 receiver locations were evaluated; 70 samples were Line-of-Sight. The study area incorporates the Virginia Polytechnic Institute and State University campus. Incorporating Fresnel zones, Interpolating elevations and calculating double blockages do not have an effect on the program's overall ability to predict signal strength. However, for obstructed pathways, it is not adequate to simply use path loss as an estimate of signal strength. Accurate estimates of diffraction gain are crucial for obstructed pathways. In addition, examination of the standard deviation for the data sets indicates that the model is independent of frequency. The average error across the frequencies is positively correlated with frequency, indicating that the model predicts signal strength better for higher frequencies. The smaller wavelengths associated with the higher frequencies require a more directional antenna and are therefore less sensitive to multipath interference. In addition, the smaller wavelengths are less able to diffract around buildings and terrain features.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartthesis.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectGISen_US
dc.subjectLMDSen_US
dc.subjectLine-of-Sight Predictionen_US
dc.subjectDiffractionen_US
dc.subjectPath Lossen_US
dc.subjectSignal Strength Predictionen_US
dc.subjectRFen_US
dc.titleRF and GIS: Field Strength Prediction for Frequencies between 900 MHz and 28 GHz.en_US
dc.typeThesisen_US
dc.contributor.departmentGeographyen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineGeographyen_US
dc.contributor.committeechairCarstensen, Laurence William Jr.en_US
dc.contributor.committeememberSweeney, Dennis G.en_US
dc.contributor.committeememberBostian, Charles W.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-08242001-132339/en_US
dc.date.sdate2001-08-24en_US
dc.date.rdate2002-08-27
dc.date.adate2001-08-27en_US


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