\setchapterpreamble[u]{% \dictum[Stobaeus] {What use is knowledge if there is no understanding?} } \chapter{Introduction to GSM and GPS} \section{Motivation} \section{Goals of the thesis} The goal of the following thesis is to: - implement the Radio Resource Location Protocol inside of OpenBSC, to the extent of delivering correct GPS assistance data to cell phone subscribers inside the GSM network - test the protocol on 5-10 different smart phones - describe and analyze the background processes taking place inside of the cell phone \chapter{Assisted GPS} \chapter{Radio Resource Location Protocol} \chapter {Working} \section{Zitieren..} citep: \citep{kopka1997latex} \\ citet: \citet{kopka1997latex} \chapter{System} Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.\todo{Referenz für lorem ipsum} Test test \chapter{Software} Author's test system operated on the ARFCN 877 channel. ARFCN (Absolute Radio Frequency Channel Number) defines the uplink and downlink channel frequency insdide the GSM network \citep{Richard2011Master}. ARFCN 877 corresponds to the uplink frequency of 1,783.2 MHz and a downlink frequency of 1,878.2 MHz, where the uplink direction represents the direction from the nanoBTS to the mobile stations and downlink the opposite direction. The decision to use the ARFCN 877 channel was derived from the fact that the channel was free, measurements were carried out with a spectrum analyzer built on the USRP hardware. \chapter{Hardware} In the following chapter the author will introduce the reader to the hardware components used in the thesis. The hardware components will be presented according to their importance of building an operational and functional GSM network with GPS localization capabilities. Firstly the nanoBTS will be introduced since it is the main hardware component used for building a basic GSM network infrastructure. Then a short insight into the used GPS receiver will be given. Additionally the mobile stations used for testing of the system will be reviewed. Finally, a hardware connection diagram will be given. \section{GSM hardware - nanoBTS} In recent years, there has been an increasing interest in deployment of private cellular networks in remote areas or for research which lead to the devolopment of diverse ``low-cost'' GSM hardware solutions. According to ip.access\footnote{http://www.ipaccess.com}, the manufacturer of nanoBTS, their hardware product is deployed for coverage of ``hard-to-reach places; in-buildings; remote areas; marine and aviation; and public spaces''. A nanoBTS with its plastic cover can be seen in Figure \ref{img:nanoBTSPlastic}. Our University GSM network consists of three nanoBTS stations. The deployed nanoBTS in author's thesis works in the 1800 MHz frequency range, for which the University of Freiburg had obtained a licence from the Federal Network Agency (German: $Bundesnetzagentur$). The transmission frequencies range between 1805-1880 MHz, with 200 KHz channel spacing and maximal output power of +13 dBm ($\approx$20 mW), whereas the receiving frequencies lie in the range between 1710-1785 MHz and same channel spacing as for transmission of 200 KHz \citep{nanoGSM2007brochure}. The key limitation of gathering more technical data lies in the fact that nanoBTS is not an open source hardware platform however, the given technical data are sufficient for reproducing and conducting the RRLP tests. \begin{figure}[ht!] \centering \includegraphics[scale=0.50]{img/nanoBTS.jpg} \caption[]{nanoBTS with its plastic cover. Image courtesy of ip.access ltd} \label{img:nanoBTSPlastic} \end{figure} The nanoBTS is equiped with an internal 0 dBi (nominal) omni-directional antenna. However, two external antennas sized 30x36 mm, one for transmission (TX) and the other one for reception (RX) of radio waves were used to extend the coverage area. These antennas are connected via the SMA connectors. By using an RF amplifier and larger antennas, for these frequency ranges, the covered area with the GSM signal reception can be increased. For the gain estimation and radiation angle of the used antennas the measurement equipment was missing and therefore was not conducted in this work. At the bottom of the nanoBTS there are 5 ports, as seen in Figure \ref{img:nanoBTSPorts}. The ports from left to right are: voltage supply, ethernet cable with power supply, USB port, TIB-IN and TIB-OUT. In the next paragraph a brief overview of each port will be given. \begin{figure}[ht!] \centering \includegraphics[scale=0.15]{img/nanoBTSPorts.jpg} \caption[]{nanoBTS with two external antennas and five connection ports} \label{img:nanoBTSPorts} \end{figure} The left most port is the power supply port used for supplying the nanoBTS with 48 V DC and is optionally used depending on the cable configuration. In author's hardware configuration the power supply port is not used. The following port is for the ethernet connection with 48 V DC power supply. This port is connected to a power supply that is supplied with the nanoBTS. It extends the ethernet connection with 48 V DC for the normal operation mode of the nanoBTS which is in the range between 38-50 V DC. The power consumtion of the nanoBTS is 13 W. More details on how to interconnect the cables will be given in section \ref{sec:hardwareConfig}. In the middle of the five port region, the mini USB port can be found. It is used by the manufacturer to write the firmware software to the nanoBTS. The last two ports are the TIB-IN and TIB-OUT port\footnote{TIB stands for Timing Interface Bus}. These two ports are used if the GSM network operator requires more than 11 channels to increase the overall capacity of the network. ``Up to 4 nanoBTS can be combined into a multiple TRX cell, increasing the number of supported users per TRX by up to 200\%. The TIB-OUT from the Master TRX must be connected to the TIB-IN of the slave TRX. This in turn has its TIB-OUT connected to the next TRX in the chain.'' \citep{multipleTRX}. The multiple TRX cell configuration will not be further discussed in this work since the purpose of the work was not to boost the capacity of a GSM network. \section{GPS Device} \label{sec:gpsDevice} \section{Hardware configuration} \label{sec:hardwareConfig} \chapter{Summary} \chapter*{Dictionary of acronyms} \begin{itemize} \item \emph{ARFCN} - Absolute Radio Frequency Channel Number - The channel number specifies the physical frequency channel used for transmission and reception inside of an BTS covered area. \item \emph{BTS} - Base Transceiver Station - \item \emph{DC} - Direct Current \item \emph{RRLP} - Radio Resource Location Protocol - The employed protocol in GSM, UMTS and other wireless networks for providing and exchange of geolocation information. \item \emph{TIB} - Time Interface Bus - The Timing Interface Bus (TIB) is used to provide clock and signalling between the nanoBTS when operating in a Multi-TRX configuration. \item \emph{TRX} - \item \emph{UMTS} - Universal Mobile Telecommunications System - Third generation mobile network based on the GSM standards. \end{itemize}