\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}{6} \contentsline {subsection}{\numberline {2.2.1}Mobile Station}{7} \contentsline {subsection}{\numberline {2.2.2}Network Subsystem}{11} \contentsline {subsubsection}{Mobile Switching Center}{11} \contentsline {subsubsection}{Home Location Register}{12} \contentsline {subsubsection}{Visitor Location Register}{13} \contentsline {subsubsection}{Equipment Identification Register}{13} \contentsline {subsubsection}{Authentication Center}{14} \contentsline {subsection}{\numberline {2.2.3}Intelligent Network}{15} \contentsline {subsection}{\numberline {2.2.4}Base Station Subsystem}{15} \contentsline {subsubsection}{Frequencies and the Cellular Principle}{16} \contentsline {subsubsection}{Base Transceiver Station}{18} \contentsline {subsubsection}{Baste Station Controller}{19} \contentsline {subsubsection}{Transcoding rate and Adaption Unit}{20} \contentsline {section}{\numberline {2.3}The $U_m$ Interface}{22} \contentsline {subsection}{\numberline {2.3.1}Layers}{22} \contentsline {subsection}{\numberline {2.3.2}The Radio Channel}{22} \contentsline {subsection}{\numberline {2.3.3}Logical Channels}{22} \contentsline {section}{\numberline {2.4}IMSI-Catcher}{22} \contentsline {subsection}{\numberline {2.4.1}Mode of Operation}{22} \contentsline {subsection}{\numberline {2.4.2}Possible Attacks}{22} \contentsline {subsection}{\numberline {2.4.3}Law situation in Germany}{22} \contentsline {chapter}{Bibliography}{I} \contentsline {chapter}{Acronyms}{III}