评估联邦和非联邦陆地移动无线电频率分配方法

U.S. DEPARTMENT OF COMMERCE - National Telecommunications and Information Administration Assessment of Federal and Non-Federal LandMobile Radio Frequency AssignmentMethodologies Bernard JoinerAlakananda PaulKim CaiEdward F. Drocella U.S. DEPARTMENT OF COMMERCECarlos M. Gutierrez, Secretary John M. R. Kneuer, Assistant Secretaryfor Communications and Information May 2007 Preface This report describes how the current frequency assignment process influences spectrumefficiency in the federal land mobile radio frequency bands. In light of the increasing demandsfor land mobile radio communications, federal spectrum managers must use frequencyassignment methods that accurately represent interference to and from systems in theenvironment to ensure that spectrum is used efficiently. The results of this report will be used tosupport the implementation of an interference-based frequency assignment process that willimprove spectrum efficiency. Standardizing the interference analysis methodologies used inidentifying interference-free frequencies in the land mobile radio bands will also improve theoverall effectiveness of the federal agencies in performing their missions. This report is one of aseries of studies being performed by the National Telecommunications and InformationAdministration to develop techniques for evaluating and improving the efficiency andeffectiveness of federal spectrum use in response to the President’s Spectrum Policy Initiative.The results of these studies will be considered as a whole in setting future policies to improvefederal spectrum efficiency. Acknowledgments The authors would like to acknowledge Craig Scammon, Thomas Sullivan, SuzetteWilliams, the members of the Interdepartment Radio Advisory Committee, the Joint SpectrumCenter, and Alion Science and Technology for their assistance in preparing this report. Executive Summary In May 2003, President Bush established the Spectrum Policy Initiative to promote thedevelopment and implementation of a United States spectrum policy for the 21stcentury. Inresponse to the Spectrum Policy Initiative, the Secretary of Commerce established a FederalGovernment Spectrum Task Force and initiated a series of public meetings to address policiesaffecting spectrum use by the federal government, state, and local governments, and the privatesector. The recommendations resulting from these activities were included in two reportsreleased by the Secretary of Commerce in June 2004. Based on the recommendations containedin these reports, the President directed the federal agencies on November 30, 2004, to plan theimplementation of the 24 recommendations contained in the reports. In March 2006, theDepartment of Commerce released the Plan to Implement Recommendations of the President’sSpectrum Policy Initiative. One of the recommendations directed the NationalTelecommunications and Information Administration (NTIA) to develop analytic approaches,software tools, and engineering techniques for evaluating and improving the efficiency of federalspectrum use. This report describes how the current frequency assignment process influencesspectrum efficiency in the land mobile radio frequency bands and proposes potentialimprovements in spectrum management practices, standards, and polices that will affectefficiency. NTIA periodically reviews and revises its frequency assignment procedures and thesupporting software tools in order to improve federal spectrum efficiency and effectiveness. Inthis report, NTIA investigates and compares two methodologies used in the land mobilefrequency bands to identify frequencies for a proposed system, considering potential interferenceto and from the existing systems operating in the same geographical area. The twomethodologies investigated are the Spectrum XXI interference analysis algorithm and analgorithm based on the Telecommunications Industry Association (TIA) TelecommunicationsSystems Bulletin 88-B (TSB-88-B). Spectrum XXI was originally developed by the Department of Defense (DOD) as acapability to rapidly identify and assign interference-free frequencies in a military tacticalenvironment. Over the past ten years, NTIA has worked with the DOD to implement theSpectrum XXI frequency assignment techniques in non-tactical environments. TSB-88-B wasdeveloped by the TIA and is primarily used by non-federal frequency coordinators forcalculating interference and assigning land mobile frequencies. As part of the investigationdocumented in this report, a technical analysis was performed comparing the interferenceanalysis methodologies used in Spectrum XXI and TSB-88-B. The analysis considered thefollowing technical areas: interference criteria, propagation models, noise models, transmitterand receiver filter models, and antenna models. Based on this comparative analysis, NTIAdetermined that for each of the technical areas examined the approach used in the Spectrum XXIinterference analysis algorithm tended to be more conservative tha