\select@language {english} \contentsline {chapter}{\numberline {1}Introduciton}{1} \contentsline {section}{\numberline {1.1}Structure}{1} \contentsline {chapter}{\numberline {2}GSM}{3} \contentsline {section}{\numberline {2.1}A Historical Perspective}{3} \contentsline {section}{\numberline {2.2}The GSM Network}{5} \contentsline {subsection}{\numberline {2.2.1}Mobile Station}{6} \contentsline {subsection}{\numberline {2.2.2}Network Subsystem}{9} \contentsline {subsubsection}{Mobile Switching Center}{9} \contentsline {subsubsection}{Home Location Register}{10} \contentsline {subsubsection}{Visitor Location Register}{12} \contentsline {subsubsection}{Equipment Identification Register}{12} \contentsline {subsubsection}{Authentication Center}{12} \contentsline {subsection}{\numberline {2.2.3}Intelligent Network}{14} \contentsline {subsection}{\numberline {2.2.4}Base Station Subsystem}{15} \contentsline {subsubsection}{Frequencies and the Cellular Principle}{15} \contentsline {subsubsection}{Base Transceiver Station}{18} \contentsline {subsubsection}{Baste Station Controller}{20} \contentsline {subsubsection}{Transcoding rate and Adaption Unit}{21} \contentsline {section}{\numberline {2.3}The $U_m$ Interface}{22} \contentsline {subsection}{\numberline {2.3.1}Radio Transmission}{23} \contentsline {subsubsection}{Frame Numbering}{23} \contentsline {subsubsection}{Burst Types}{25} \contentsline {subsection}{\numberline {2.3.2}Logical Channels}{26} \contentsline {subsubsection}{Dedicated Channels}{27} \contentsline {subsubsection}{Common Channels}{27} \contentsline {subsubsection}{Combinations}{28} \contentsline {subsection}{\numberline {2.3.3}Layers}{29} \contentsline {paragraph}{Physical Layer (Layer 1):}{29} \contentsline {paragraph}{Data Link (Layer 2):}{31} \contentsline {paragraph}{Network (Layer 3):}{31} \contentsline {section}{\numberline {2.4}IMSI-Catcher}{31} \contentsline {subsection}{\numberline {2.4.1}Mode of Operation}{32} \contentsline {subsubsection}{Attacks}{34} \contentsline {paragraph}{\gls {ms} is in normal cell selection mode:}{34} \contentsline {paragraph}{\gls {ms} is already connected to a network:}{35} \contentsline {subsubsection}{Risks and Irregularities}{35} \contentsline {subsection}{\numberline {2.4.2}Law Situation in Germany}{35} \contentsline {chapter}{\numberline {3}IMSI Catcher Detection}{37} \contentsline {section}{\numberline {3.1}Frameworks and Hardware}{37} \contentsline {subsection}{\numberline {3.1.1}OsmoconBB}{37} \contentsline {subsection}{\numberline {3.1.2}Motorola C123}{37} \contentsline {subsection}{\numberline {3.1.3}GNS 5870 MFI}{37} \contentsline {section}{\numberline {3.2}Procedure}{37} \contentsline {subsection}{\numberline {3.2.1}Information Gathering}{37} \contentsline {subsection}{\numberline {3.2.2}Information Evaluation}{37} \contentsline {subsection}{\numberline {3.2.3}Further Improvements}{37} \contentsline {section}{\numberline {3.3}Implementation}{37} \contentsline {section}{\numberline {3.4}IMSI Catcher Detection System}{37} \contentsline {subsection}{\numberline {3.4.1}Configuration}{37} \contentsline {subsection}{\numberline {3.4.2}Operation}{37} \contentsline {chapter}{\numberline {4}Evaluation}{39} \contentsline {section}{\numberline {4.1}Open Field Statistics}{39} \contentsline {subsection}{\numberline {4.1.1}Bayesian Filter}{39} \contentsline {subsection}{\numberline {4.1.2}Detection System}{39} \contentsline {section}{\numberline {4.2}Example Scenarios}{39} \contentsline {chapter}{\numberline {5}Conclusion}{41} \contentsline {section}{\numberline {5.1}Future Work}{41} \contentsline {chapter}{Bibliography}{I} \contentsline {chapter}{Acronyms}{VII}