\select@language {english} \addvspace {10\p@ } \addvspace {10\p@ } \contentsline {figure}{\numberline {2.1}{\ignorespaces Growth of mobile GSM subscriptions. Compiled from \cite {GSM2009,GSM_history2011,GSM_stats2011}}}{5} \contentsline {figure}{\numberline {2.2}{\ignorespaces The 3GPP Logo}}{5} \contentsline {figure}{\numberline {2.3}{\ignorespaces The main components of a GSM network.}}{6} \contentsline {figure}{\numberline {2.4}{\ignorespaces Authentication procedure}}{14} \contentsline {figure}{\numberline {2.5}{\ignorespaces Mapping of functional entities on the 900Mhz band.}}{16} \contentsline {figure}{\numberline {2.6}{\ignorespaces Theoretical arrangement of radio cells compared to a realistic alignment. Cells with the same number share the same frequency \cite {GSM2009}.}}{18} \contentsline {figure}{\numberline {2.7}{\ignorespaces Common base station configurations. Compiled from \cite {protocols1999}.}}{18} \contentsline {figure}{\numberline {2.8}{\ignorespaces Cyphering procedure for one frame of voice data. Adopted from \cite {kommsys2006}.}}{21}