\newpage{} \section*{\vfill{} Erklärung} Hiermit erkläre ich, dass ich diese Abschlussarbeit selbständig verfasst habe, keine anderen als die angegebenen Quellen/Hilfsmittel verwendet habe und alle Stellen, die wörtlich oder sinngemäß aus veröffentlichten Schriften entnommen wurden, als solche kenntlich gemacht habe. Darüber hinaus erkläre ich, dass diese Abschlussarbeit nicht, auch nicht auszugsweise, bereits für eine andere Prüfung angefertigt wurde. \vspace{3cm} \begin{minipage}[t][1\totalheight]{0.35\textwidth} Ort, Datum \\(Place, Date) \end{minipage}\hfill{} \begin{minipage}[t][1\totalheight]{0.45\textwidth} Unterschrift \\(Signature) \end{minipage} \newpage{} \section*{\vfill{} Acknowledgment} I would like to thank my supervisors Konrad Meier and Dennis Wehrle for their help and encouraging talks during the thesis. Beside the help from the supervisors I would like to thank my family and friends who supported me through my master studies, and the entire Communication systems department for their support, free coffee and to Prof. Dr. Gerhard Schneider for making all the required hardware available. I would like to thank Prof. Dr. Christian Schindelhauer for writing the recommendation letter so that DAAD could extend my scholarship and stay in Freiburg. I would like to thank my friend Mirza Hamza from the Telecommunication department at the Faculty of Electrical Engineering in Sarajevo for proofreading the AGPS chapter. I would like to thank Sebastian Schmelzer for his LaTeX tips, Michael Neves Pereira and Jonathan Bauer for borrowing me their cell phones to test my localization system with as well as Johan Latocha for patiently explaining me words I did not understand in the German language and for showing me Inkscape. I would like to thank Richard Zahoransky for the helping discussions about various GSM topics. Thank go to Holger Hans Peter Freyther as well, who gave me a hint where to modify OpenBSC to make an independent data channel interface with a cell phone. Things which have not been done before are intellectually seductive in some way and it kept me motivated and working during the tough periods. \newpage \section*{Abstract}