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-rw-r--r--vorlagen/thesis/src/kapitel_x.tex58
1 files changed, 25 insertions, 33 deletions
diff --git a/vorlagen/thesis/src/kapitel_x.tex b/vorlagen/thesis/src/kapitel_x.tex
index 445f26e..e2475c6 100644
--- a/vorlagen/thesis/src/kapitel_x.tex
+++ b/vorlagen/thesis/src/kapitel_x.tex
@@ -143,7 +143,8 @@ another frequency} from one BTS to another during an active connection when the
strength is higher than on the currently-connected BTS. This signal reception strength is known as Received signal strength (RSS).
RSS are measurement reports transmitted from the cell phone to the BTS.
RSS is used to determine if the handover process should be triggered or not \citep{Richard2011Master}.
-BSC is connected to the Transcoding Rate and Adaptation Unit (TRAU). This builds the Base Station Subsystem (BSS), as it can
+BSC is connected to the Transcoding Rate, Adaptation Unit (TRAU) and Serving Mobile Location Center (SMLC).
+The SMLC node contains the functionality to support location services for the GSM network \citep{3GPPTS03.71}. This builds the Base Station Subsystem (BSS), as it can
be seen in figure \ref{img:GSMBig}, on left side inside of the gray dashed line rectangle. Inside of the BSS, TRAU
is responsibe for compressing and decompressing speech between the cell phone and a speech signal from the other side,
from 64 kbps to 16 or 8 kbps depending if it is a full or half rate channel.
@@ -185,7 +186,7 @@ the networks are employed. The reason why different frequencies are used is beca
wireless systems and used telecommunication standards. Particularly in Germany, the Federal Network Agency (German: $Bundesnetzagentur$) is the
responsible organisation for assigning different frequencies to GSM operators since these frequencies belong
to the group of licensed frequencies and are not allowed to be used by everyone. In Germany the used frequency bands
-are EGSM900 and GSM1800, their frequency ranges can be seen in table \ref{tbl:GSMfreqs} \citep{konrad}.
+are GSM900 and GSM1800, their frequency ranges can be seen in table \ref{tbl:GSMfreqs} \citep{konrad}.
These frequency bands are divided into 200 KHz channels,
for a frequency band range of 35 MHz there are 175 operating
channels. This technique is called Frequency Division Multiple Access (FDMA) and
@@ -201,7 +202,7 @@ It is important to distinguish uplink and downlink frequencies.
Uplink frequency is used when the cell phone transmits data
to the network operator, whereas downlink from the network operator to the cell phone. GSM is a full duplex communication
system, at the same time the cell phone or the network operator can send and receive data.
-Although the equivalent ARFCN number is used for uplink and downlink, the frequencies are shifted 45 MHz in EGSM900/GSM900 and
+Although the equivalent ARFCN number is used for uplink and downlink channels, the frequencies are shifted 45 MHz in GSM900 and
95 MHz in GSM1800 as it can be seen in figure \ref{img:GSMFreqRangChannel} for GSM900.
\begin {table}[ht]
\caption{GSM operating frequencies in Germany}
@@ -235,10 +236,7 @@ full rate\footnote{Human speech has a frequency bandwidth between 0 and 4000 Hz
Human voice is by its nature analog and requires to be converted into a digital stream of ones and zeros.
By Nyquist-Shannon sampling theorem the sampling frequency must be at least two times greater
than the sampled frequency and with an 8 bit Analog to Digital Converter (ADC) this defines the
-64 kbps required to transfer voice ($2\cdot4000 Hz\cdot8 = 64000$).}. Since new wireless services are
-data oriented and the networks become packet networks this type of modulating data had to be changed,
-3G and 4G networks use different frequency ranges and technique to modulate and demodulate data.
-
+64 kbps required to transfer voice ($2\cdot4000 Hz\cdot8 = 64000$).}.
\newpage
The idea of employing TDMA on FDMA in the GSM900 band can be seen in figure \ref{img:GSMFreqTime}.
Each time slot duration is $\approx$577 $\mu s$, all 8 time slots have a period of $\approx$ 4.615 $ms$
@@ -389,7 +387,7 @@ distinguished from other BTS's.
\begin{figure}[ht!]
\centering
\includegraphics[scale=0.70]{img/CellID.pdf}
- \caption{Cell-ID position estimation technique where a mobile user can be connected to only one BTS.}
+ \caption{Cell-ID position estimation technique.}
\label{img:cellid}
\end{figure}
@@ -1372,9 +1370,7 @@ position estimation from the derived data in the previous stage.
\section{RRLP Request}
RRLP represents the connection/protocol between the Serving Mobile Location Center (SMLC)
and the standalone handset, in this case the MS \citep[Chapter 5]{harper2010server-side}.
-The SMLC node contains the functionality to support
-location services for the GSM network \citep{3GPPTS03.71}. SMLC is located on the Base
-Station Controller (BSC) \citep{3GPPTS03.71}. SMLC' primary function is to manage
+SMLC is located on the BSC \citep{3GPPTS03.71}. SMLC' primary function is to manage
the overall coordination and scheduling of resources required to perform the localization of the MS.
SMLC controls the LMU's as well but since in this work no LMU were available this part
can be skipped as well as the description of E-OTD and UL-TDOA localization. Before an attempt is made, of requesting the SMLC to initialize an RRLP request, an SDCCH connection
@@ -2137,8 +2133,8 @@ FixType ::= INTEGER {
\chapter{Implementation}
\label{Implementation}
-The aim of this chapter is to give the reader a review of the employed hardware
-and the implemented software. The main idea of author's approach to the problem is
+The aim of this chapter is to give the reader a review of the employed hardware,
+testbed setup and the implemented software. The main idea of author's approach to the problem is
discussed in this chapter. The implementation can be divided into two stages.
The first stage being the inital phase of the thesis where the initial system has
been set up to perform RRLP tests. The second stage can be divided into two
@@ -2220,7 +2216,7 @@ PSU and nanoBTS should not be longer than 100 m \citep{installnanoBTS}.
\caption{Cable connections, showing interconnection diagram}
\label{img:connectionDiagram}
\end{figure}
-
+\newpage
\section{Initial phase of RRLP testbed setup}
Traditionally all radio communication systems are hard wired and
the hardware is developed to do only one fixed function as the
@@ -2341,8 +2337,9 @@ verification of their correctness, construction of RRLP packets according to
the ASN.1 standard, conversion of it to PER and at last saving in the
hexadecimal form in a text file.
+\newpage
In the almanac
-and ephemeris files, downloaded from NASA and Trimble, assistance data were stored
+and ephemeris files, downloaded from Navigation Center of the US Coast Guard and Trimble, assistance data were stored
for 32 different GPS satellites. Contrary to expectations after the generated
RRLP packets have been analysed, Heimerl's code produced RRLP assistance
data packets with only valid data for one satellite but duplicated 32 times.
@@ -2528,21 +2525,16 @@ table \ref{tbl:smartphones}.
\label{tbl:smartphones}\centering
%\rowcolor{2}{light-gray}{}
\scriptsize\fontfamily{iwona}\selectfont
-\begin{tabular}{ll}
+\begin{tabular}{llll}
\toprule
%$D$&&$P_u$&$\sigma_N$\\
-\textbf{Cell phone} & \textbf{Manufacturer \& Country}\\\toprule
-$Defy$&Motorola, USA\\\midrule
-$iPhone$ $4$&Apple, USA\\\midrule
-$iPhone$ $3GS$&Apple, USA\\\midrule
-$G1$&Google, USA\\\midrule
-$Galaxy$ $S2$&Samsung, South Korea\\\midrule
-$Galaxy$ $S3$&Samsung, South Korea\\\midrule
-$Galaxy$ $Nexus$ $i9250$&Samsung, South Korea\\\midrule
-$E71$&Nokia, Finland\\\midrule
-$N95$&Nokia, Finland\\\midrule
-$Desire$ $S$&HTC, Taiwan\\\midrule
-$Blade$&ZTE, P.R. of China
+\textbf{Cell phone} & \textbf{Manufacturer \& Country}&\textbf{Cell phone} & \textbf{Manufacturer \& Country}\\\toprule
+$Defy$&Motorola, USA&$Galaxy$ $Nexus$ $i9250$&Samsung, South Korea\\\midrule
+$iPhone$ $4$&Apple, USA&$E71$&Nokia, Finland\\\midrule
+$iPhone$ $3GS$&Apple, USA&$N95$&Nokia, Finland\\\midrule
+$G1$&Google, USA&$Desire$ $S$&HTC, Taiwan\\\midrule
+$Galaxy$ $S2$&Samsung, South Korea&$Blade$&ZTE, P.R. of China\\\midrule
+$Galaxy$ $S3$&Samsung, South Korea
\\\bottomrule
\end {tabular}
\end {table}
@@ -2792,18 +2784,18 @@ predefined acquisition sensitivity even assistance data can not help.
Antenna polarization and the position of the cell phone matter as well.
Correctness of assistance data in almanac and ephemeris data can not be
-verified. The author had to rely and trust NASA and Trimble as sources
+verified. The author had to rely and trust the Navigation Center of the US Coast Guard and Trimble as sources
although errors were confirmed by different studies in \citep{Stanford-Ephem-Errors}
\citep{NASA-Ephem-Errors}. Errors can be confirmed by the author in
ephemeris data as well (URA values were out of range specified by the standard).
These errors were not continual but appeared occasionally and these errors
-were inside of the assistance data provided by NASA.
+were inside of the assistance data provided by Navigation Center of the US Coast Guard (NVCS).
\section{Future work}
\label{sec:futWork}
The system could be extended with a GPS device that delivers raw GPS data
-instead of using the data provided by NASA and Trimble. Obtained data by the GPS
-could be compared to the data provided by NASA or other GPS observation stations
+instead of using the data provided by NVCS and Trimble. Obtained data by the GPS
+could be compared to the data provided by NVCS or other GPS observation stations
and verified for errors. By having more redundant sources of same information,
mistakes in the output could be eliminated. More sources of redundant data could
indicate the correctness of assistance data.
@@ -2821,7 +2813,7 @@ movement of GSM users \citep{predictMovements}.
%Tests could be performed if it possible if it can be tricked out by the software Dennis mentioned (protect my privacy)!
-\chapter{Summary and discussion}
+\chapter{Summary and security issues}
%This thesis has investigated how difficult it is to integrate mobile assisted GPS localization in GSM
%Networks. The aim of this work was set out to implement the ``first'' working open source RRLP
%implementation in GSM networks, as well as to determine and evaluate the limits of this localization