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--- a/vorlagen/thesis/src/kapitel_x.tex
+++ b/vorlagen/thesis/src/kapitel_x.tex
@@ -40,8 +40,8 @@ in the system and have better LBS performance as well as higher accuracy compare
%and GPS positioning. The author shall then describe the goals of his thesis.
In this thesis the author will provide the theoretical and practical
knowledge required for building a localization system of mobile users
-inside of a 2G GSM network by taking advantage of the already-existing AGPS receivers inside of smart phones.
-Another reason why the AGPS method was prefered over other localization methods is because
+inside of a 2G GSM network by taking advantage of the already-existing Assisted-GPS (AGPS) receivers inside of smart phones.
+Another reason why the AGPS method was preferred over other localization methods is because
the position estimation is sufficiently precise and accurate compared to other methods.
Further advantage over other positioning techniques is that smart phones with an AGPS
receiver represent slightly less than 50\% of the total cell phone market in the most
@@ -86,7 +86,7 @@ development and implementation process. More details on the hardware connections
shall be provided in chapter 6. In chapter 7 test results and the test environment
will be presented. Chapter 8 will provide a summary of the entire system. The appendix
contains details for configuring the entire system and for obtaining the same results.
-This thesis includes a USB stick with the source code developed during the work on this thesis.
+This thesis includes a CD with the source code developed during the work on this thesis.
@@ -115,14 +115,14 @@ and provides a connection with the cell phone \citep[Chapter 3]{0890064717}. Thi
BTS and the cell phone is called the \textit{$U_m$ interface}, as shown in figure \ref{img:GSMBig}. A BTS can serve up
to six users on one frequency in full duplex mode since two out of eight time slot are used for broadcasting of signalling and system information.
%transmitted in the broadcast control channel (BCCH).
-By sectorizing BTSs with different frequencies and by altering the configuration
+By sectorising BTSs with different frequencies and by altering the configuration
the number of six mobile users can be increased per sector.
The BTS are divided into geographical regions\footnote{Usually they are represented as hexagons but it could take
-any other geometric shape.} by their signal coverage. A BTS consists of a RF tranceiver, internal clock and modulator/demodulator. The function of the RF transceiver is
+any other geometric shape.} by their signal coverage. A BTS consists of a RF transceiver, internal clock and modulator/demodulator. The function of the RF transceiver is
to enable the reception and transmission on the uplink and downlink channel for the cell frequency where the
BTS is located\footnote{Cell is the area covered with GSM signal and from which a cell phone can communicate with a BTS.}.
The main function of the internal clock is to supply the BTS with a frequency such that the internal
-circuits can produce frames seperated in time domain. The internal clock has to be sufficiently accurate for the GSM
+circuits can produce frames separated in time domain. The internal clock has to be sufficiently accurate for the GSM
network to work, an accuracy of at least $\pm$5 ppm (parts per million) \citep{dennis}. If the GSM network is synchronized,
this internal clock is not employed but an external clock generated signal from an atomic clock. The GSM network
must be synchronized for some of the position localization techniques discussed in this chapter. Devices providing the
@@ -147,7 +147,7 @@ RSS is used to determine if the handover process should be triggered or not \cit
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,
+is responsible 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.
The next subsystem block is the Network Switching Subsystem (NSS), as it can be seen on figure \ref{img:GSMBig}, on right
@@ -183,7 +183,7 @@ ought to be tracked if they register \citep[Chapter 4]{0890064717}.
The main task of GSM networks was to enable wireless voice transmission between GSM and other GSM/telephone users
inside of switched networks. It was not designed to be used with data services which are a necessity in today's standards.
GSM networks are worldwide spread and work on different frequency spectrums depending on the country where
-the networks are deployed. The reason why different frequencies are used is because of intereference with different
+the networks are deployed. The reason why different frequencies are used is because of interference with different
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
@@ -206,7 +206,7 @@ system, at the same time the cell phone or the network operator can send and rec
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}
+\caption{GSM operating frequencies in Germany.}
\label{tbl:GSMfreqs}\centering
%\rowcolor{2}{light-gray}{}
\scriptsize\fontfamily{iwona}\selectfont
@@ -277,9 +277,9 @@ was defined due to internal synchronization of the GSM network and cyphering bet
\section{Logical channels and the data channel}
\label{sec:SDCCHChan}
-In this section more details will be given on logical channels and the procedure to initialize (open) a Standalone Dedicated Control Channel (SDCCH).
+In this section more details will be given on logical channels and the procedure to initialize (open) a Stand-alone Dedicated Control Channel (SDCCH).
As stated in section \ref{sec:GSMNetStruct}, logical channels can be divided in two groups,
-traffic channels (TCH) and signalling/controlling channels (CCH). The former are employed for transfering payload data like speech and message data
+traffic channels (TCH) and signalling/controlling channels (CCH). The former are employed for transferring payload data like speech and message data
and the latter for managing and synchronizing the GSM network \citep[Chapter 4]{0470030704}. For the purposes of this thesis,
the term ``Mobile Station'' (MS) will be used to refer to a cell phone or to designate the user one intends to locate.
Traffic and signalling channels can be split up by their usage, as given in tables \ref{tbl:tchChannels} and \ref{tbl:cchChannels}.
@@ -319,7 +319,7 @@ Paging channel&PCH &Paging request is sent out when MS has& MS$\leftarrow$BSS\\
&&incoming traffic (phone call, SMS, etc.)\\\midrule
Cell broadcast channel&CBCH&Required to broadcast a message to all& MS$\leftarrow$BSS\\
&&MS inside of a MSC (e.q. weather forecast)\\\midrule
-Standalone dedicated control channel&SDCCH&Exchange of signalling information between&MS$\leftrightarrow$BSS\\
+Stand-alone dedicated control channel&SDCCH&Exchange of signalling information between&MS$\leftrightarrow$BSS\\
&&MS and BTS when no TCH is active\\\midrule
Slow associated control channel&SACCH&Transmission of signalling data during an active&MS$\leftrightarrow$BSS\\
&&TCH connection (signal strength and sync. data)\\\midrule
@@ -332,7 +332,7 @@ Random access channel&RACH&Request from MS to BTS for a communication& MS$\right
\end {tabular}
\end {table}
-The protocol scenario occuring in this work can be seen in figure \ref{img:SDCCHReq} \citep{0470844574}.
+The protocol scenario occurring in this work can be seen in figure \ref{img:SDCCHReq} \citep{0470844574}.
In order for the assistance data to be delivered to the MS, an SDCCH channel has to be initialized.
This occurs in the following procedure, the BTS where the MS has been lastly active or idle
broadcast a paging request (PCH channel) to the selected MS. After the MS obtains the paging request, the MS shall
@@ -346,7 +346,7 @@ whereas the acknowledgements, errors or the position are delivered to the BTS (B
In the case if all SDCCH channels are reserved, the network will queue an SDCCH request for later assignment
or it may send an assignment reject.
%Once the SDCCH channel connection has been established, data can be transmitted in both directions.
-While an active SDCCH conection exists, the MS will receive and transmit radio link control
+While an active SDCCH connection exists, the MS will receive and transmit radio link control
messages (signal strength and synchronization data) on the SACCH channel \citep{0470844574}.
\begin{figure}[ht!]
@@ -365,7 +365,7 @@ Over the past decade the GSM and its derivative networks became more popular and
the demands grew for new services such as Internet connectivity and LBS. Emergency services wanted
to be able to localize mobile users in emergency situations like snow avalanches or other non-typical
daily emergency situations \citep{0849333490}. This demand led to the
-devolopment of various approaches that differ in complexity and in the degree of accuracy of position fixes.
+development of various approaches that differ in complexity and in the degree of accuracy of position fixes.
However, the user positioning was limited by existing technology standards, and any improvement would require extremely
expensive cost modifications to the existing network infrastructures. Several different ideas have been put forward to
localize mobile users while avoiding these potential problems.
@@ -401,7 +401,7 @@ distinguished from other BTS's.
%where the GSM subscriber does not even notice that he/she is being called since there is no ringing
%or any other sign that an idle connection is being performed on the MS \citep[Chapter 4]{3GPPTS03.71}.
%If there are more than one antenna, then the MS location can be even more precisely specified.
-%This can still be inaccurate, however, because of multipath signal reflections.
+%This can still be inaccurate, however, because of multi-path signal reflections.
%In urban environments it is usually the case that there is no optical line of sight between the BTS and MS,
%so while the signal propagates from the BTS to the MS and vice versa it may be reflected by buildings
%or other objects which add extra propagation time (extra range to the distance).
@@ -445,12 +445,12 @@ signal arrival and for this reason have been grouped together.
E-OTD stands for Enhanced Observed Time Difference. This technique requires the GSM network to be
clock-synchronized. The clock synchronization of the GSM network can be achieved with
a Location Measurement Unit (LMU) \citep{ETSI.TS.125.111}. LMU's provide the precise time to the BTS's
-by having an atomic clock synchronized with the BTS on a seperate location from the BTS or
+by having an atomic clock synchronized with the BTS on a separate location from the BTS or
by providing a special GPS device at the BTS' location that can provide the precise time \citep{ETSI.TS.125.111}.
The clock synchronization of the MS and the BTS is required because the E-OTD technique
takes advantage of measuring signal propagation time.
A data signal with precise up-to-date time information is transmitted from three or more spatially distinct BTS's at the same time
-and then propagation time is measured on the MS (all these BTS's must be detecable by the MS itself) \citep{200mRangeEOTD}.
+and then propagation time is measured on the MS (all these BTS's must be detectable by the MS itself) \citep{200mRangeEOTD}.
Once the difference in time is known between when the signal was transmitted and when it was received,
it is easy to estimate the relative position to the BTS's with hyperbolic trilateration \citep{200mRangeEOTD}
\citep[Chapter 4]{3GPPTS03.71}.
@@ -465,7 +465,7 @@ the absolute location of the BTS's. The basic idea can be seen in figure \ref{im
the MS.}
\label{img:eotdLoc}
\end{figure}
-E-OTD requires the cell phone to be equiped with firmware to perform these measurements but does
+E-OTD requires the cell phone to be equipped with firmware to perform these measurements but does
not require new or external hardware. The accuracy of this method lies in the range between 50-200 m, depending
on the location of the MS \citep{malik2009rtls}. This method is can still be susceptible to the multipath signal problem, however.
E-OTD is a handset-based position estimation technique.
@@ -478,7 +478,7 @@ measure the waiting time between the handover request signal itself and the tran
Using the observed time difference, the BTS's can compute the location of the MS. It is important to note that this
position estimation technique takes place while there is an active call on the MS or the BTS makes a silent call
to the MS where the mobile user is not aware of being tracked \citep{malik2009rtls}. This technique is slightly
-less accure than E-OTD; the accuracy lies between 50-300 m \citep{200mRangeEOTD}. The unsynchronized operation of
+less accurate than E-OTD; the accuracy lies between 50-300 m \citep{200mRangeEOTD}. The unsynchronized operation of
the GSM network makes these two techniques impossible without clock synchronization. One microsecond error would produce
an error of around 300 m. The advantage of UL-TDOA over E-OTD lies in the fact that no extra software modifications
have to be made to the cell phone and this technique works on every cell phone. UL-TDOA is a network-based position
@@ -495,14 +495,13 @@ In this section, two more techniques shall be briefly described: Angle-of-Arriva
interpolate the intersection point where the MS is located.}
\label{img:aoadLoc}
\end{figure}
-
Angle-of-Arrival (AOA) is a localization technique that exploits a geometric fact that by knowing at least
two angles from two known points, i.e. BTS's, it is possible to construct the third triangle point (intersection point).
The intersection point represents the location of the MS. The angle is derived by a burst
signal transmitted from the MS and the time difference of arrival for different elements of the burst
signal. Once the angle is computed, it is straightforward to find the intersection point.
This technique requires the BTS's to be synchronized with LMU's and to be in line of sight with the BTS's,
-otherwise this method shall develiver poor position results. It belongs to the group of network based
+otherwise this method shall deliver poor position results. It belongs to the group of network based
position estimation techniques.
\begin{figure}[ht!]
@@ -563,8 +562,8 @@ AGPS receivers can drastically decrease the waiting time required to estimate th
compared to GPS receivers if ``exact time'' is known \citep[Chapter 4]{diggelen2009a-gps}.
AGPS works by exploiting the existing navigation satellite network.
This method does not work on every cell phone as do the aforementioned methods.
-It requires the cell phones to be equiped with an AGPS receiver.
-From this point on, cell phones with an AGPS receiver shall be refered to as smart phones
+It requires the cell phones to be equipped with an AGPS receiver.
+From this point on, cell phones with an AGPS receiver shall be referred to as smart phones
since they have another potential use aside from the default communication application. The AGPS
position estimation technique is a hybrid-based technique because the position is estimated
with the help of the handset and the network provider.
@@ -602,9 +601,9 @@ to employ this technique to get positions of GSM users with smart phones.
\caption{GPS Simple working principle, a) example in 3D space with spheres b) example in 2D space with circles.}
\label{img:GPSSimplePrinciple}
\end{figure}
-In the new global economy age, GPS positioning has become of important value for various services
+In the new global economy age, GPS (Global Positioning System) positioning has become of important value for various services
and businesses. It has been growing at a rate of 30\% in the past few years and the application
-market is expected to be worth \euro 240 milliard by 2020 only in Europe \citep{gpsMoney}.
+market is expected to be worth \euro 240 Millard by 2020 only in Europe \citep{gpsMoney}.
The goal of this chapter is to bring more details and insights of how GPS receivers work.
The chapter is divided in few sections that explain what type of data are transmitted by the satellites.
how they are modulated before transmission, demodulated on the receiver and how the search space works to
@@ -637,7 +636,7 @@ The aim of this section is to give the reader an overview of the transmitted GPS
to understand what type of processing takes place on the GPS satellite itself.
As discussed in the paragraph earlier, to estimate the position of the GPS receiver, it is
important to know the position of the satellite at the moment of signal transmission. Prior to
-releasing the data in the athmosphere, they need to be modulated in order for the GPS receiver
+releasing the data in the atmosphere, they need to be modulated in order for the GPS receiver
to receive the data.
Each one of the GPS satellites transmits the same type of information.
@@ -653,8 +652,8 @@ user's position.
\label{img:gpsframe}
\end{figure}
Each subframe can be divided into three fields of data,
-as shown in figure \ref{img:gpssubframe}, telemetry (TLM),
-handover word (HOW) and rest of the data (navigation data).
+as shown in figure \ref{img:gpssubframe}, Telemetry (TLM),
+Handover Word (HOW) and rest of the data (navigation data).
TLM is the first word of the subframe and consists of
a unique preamble used to synchronize and identify
the subframes \citep{9780817643904}. HOW is the second
@@ -718,7 +717,7 @@ Once the 25 frames have been transmitted, the process is repeated again.
%\ref{sec:CAdemod} and \ref{sec:2dSearch}.
-The data are modulated using the binary phase shift keying (BPSK) technique. The
+The data are modulated using the Binary Phase Shift Keying (BPSK) technique. The
newly modulated signal, denoted as \textit{L1}, and it is emitted from the satellite's
directed antennas toward Earth \citep{GPS-Guide}. The BPSK technique works by changing
the phase of the carrier signal for $180^{\circ}$ at the moment of bit toggle (flipping) in the
@@ -727,7 +726,7 @@ Basic principle of this technique can be seen in figure \ref{img:bpskmod}. The c
for GPS BPSK modulation is centered at a frequency of 1575.42 MHz \citep{9780817643904}.
These signals travel an average distance of $20200 \, km$ from the satellite to the GPS receiver
and are affected by various sources of noise. BPSK modulation is mostly used for satellite links
-because of its simplicity, immunity to noise and signal intereference for the cost of
+because of its simplicity, immunity to noise and signal interference for the cost of
low speed data transfer rates \citep[Chapter 1]{9780849316579}.
\begin{figure}[ht!]
@@ -753,7 +752,8 @@ PRN sequences have similar autocorrelation properties as noise, when it is shift
time domain it has a low correlation value whereas when it is matched with exact image of itself
it produces a high correlation peak \citep[Chapter 3]{bensky2008wireless}. This property is used
for identifying the satellites and for finding the exact phase shift. This phase shift
-is a consequence of the relationship between the instantaneous frequency and instantaneous phase,
+is a consequence of the relationship between the instantaneous frequency $f(t)$ and instantaneous phase $\phi(t)$
+at time instance $t$,
the relationship between frequency and phase can be seen in equations \eqref{eq:freqPhase}
and \eqref{eq:phaseFreq}. In other words, due to the Doppler effect the phase of the PRN sequence is
disordered. Without the exact phase shift it is not possible to demodulate the original data (TLM, HOW and
@@ -764,11 +764,11 @@ f(t)=\frac{1}{2\pi}\frac{\partial}{\partial t}\phi(t)
\end{equation}
\begin{equation}
\label{eq:phaseFreq}
-\phi(t) = 2\pi \int_{-\infty}^{t} f(\tau) d\tau
+\phi(t) = 2\pi \int_{-\infty}^{t} f(t) dt
\end{equation}
The second important property of PRN sequences is the property of
orthogonality. This property enables the reception of different data on the same frequency,
-also known as code division multiple access (CDMA). It is important to note that the PRN sequences
+also known as Code Division Multiple Access (CDMA). It is important to note that the PRN sequences
must have a higher frequency rate than the data, i.e. the bit duration of a PRN sequence is much shorter
than of the data \citep[Chapter 3]{bensky2008wireless}. Single bits in PRN sequences are called \textit{chips}
and the complete sequence as \textit{code} \citep[Chapter 3]{bensky2008wireless}. This newly generated
@@ -813,14 +813,14 @@ S(t) = \sqrt{\frac{P}{2}}d_{C/A}cos(2\pi f_{c}+\varphi_{GPS}) + n(t)
% \section{GPS signal acquisition and demodulation}
% \label{sec:SigDemod}
-% GPS satellites\footnote{Ssatellites are named as space vehicles
-% in GPS terminology and the abrevation SV is used in the equation notations
+% GPS satellites\footnote{Satellites are named as space vehicles
+% in GPS terminology and the abbreviation SV is used in the equation notations
% to denote a parameter related to the satellite itself.}
% orbiting our planet, at a distance of approximately $20200 \, km$,
-% are equiped with precise atomic clocks \citep[Chapter 2.7]{diggelen2009a-gps}.
+% are equipped with precise atomic clocks \citep[Chapter 2.7]{diggelen2009a-gps}.
% These atomic clocks are calibrated and maintained on
% a daily basis by the U.S. Air Force \citep{GPS-Pentagon}.
-% The time the atomic clock generate, refered earlier as GPS
+% The time the atomic clock generate, referred earlier as GPS
% system time, denoted as $t_{SV}$, is generated as a time stamp at the moment
% of the subframe broadcast \citep{GPS-Interface-Specification}.
% In addition to the
@@ -912,7 +912,7 @@ $\varphi_{a}$ the phase shift error
caused by propagation delays in the ionosphere
and troposphere respectively, $\delta \varphi_{DE}$ the phase shift
caused by the Doppler effect and $\delta \varphi_{w}$
-is the wideband noise phase shift.
+is the wide-band noise phase shift.
\begin{equation}
\label{eq:phaseShift}
\varphi_{o} = \varphi_{GPS}+ \delta\varphi_{SV} + \varphi_{a} +\delta \varphi_{DE} + \delta \varphi_{w}
@@ -930,7 +930,7 @@ equals zero.
\Delta \varphi = \varphi_{o} - \varphi_{rec}
\end{equation}
The circuit responsible for generating the same
-carrier wave is the phase locked loop (PLL).
+carrier wave is the Phase Locked Loop (PLL).
The PLL circuit is a feedback loop that modifies the synthesized wave parameters
such that $\Delta \varphi \approx 0$, a phase shift is shown in figure \ref{img:phaseShift}.
\begin{figure}[ht!]
@@ -958,7 +958,7 @@ As a result of the previous step, one can continue with
the demodulation of the C/A wave. Demodulating the C/A wave
with the PRN code will result in the required data for
estimating the position.
-Each tracked GPS satellite signal is demodulated seperately
+Each tracked GPS satellite signal is demodulated separately
using the same PRN code, code chipping rate and carrier frequency-phase
for the given satellite \citep[Chapter 4]{understandGPS}.
The carrier frequency-phase was determined in the previous step.
@@ -978,8 +978,8 @@ For the particular example, the matching phase shift was achieved with
the second replica PRN code, with a phase shift of $\tau=0$ but
there could be a case with any other value of $\tau$, $\tau\in[0,1022]$.
Implementation of the PRN code synthesizer depends on the GPS receiver
-manufacturer but it is usually implemented as a linear feedback shift
-registers (LFSR) that produces an output according to a predefined function $f(\tau)$.
+manufacturer but it is usually implemented as a Linear Feedback Shift
+Registers (LFSR) that produces an output according to a predefined function $f(\tau)$.
This function, $f(\tau)$, generates an PRN code, that is
delayed in phase by $\tau$, where $\tau$ is a multiple of the chipping
rate period $T_{c}=977.5 \,ns$. This demodulation process, of finding the correct chipping rate,
@@ -1013,7 +1013,7 @@ range for $\approx 1.46 \,\mathrm{Hz}$. On the other hand, the frequency offset
oscillator in the GPS receiver can not be ignored. Function of the reference
oscillator is to give the GPS receiver the clock pulse required for all
the computations and comparisons in the process of signal demodulation.
-The frequency search space is ``additionaly affected for $1.575 \, \mathrm{kHz}$
+The frequency search space is ``additionally affected for $1.575 \, \mathrm{kHz}$
of unknown frequency offset for each $1 \, \mathrm{ppm}$
(\textit{parts per million}) of the unknown receiver
oscillator offset'' \citep[Chapter 3]{diggelen2009a-gps}. The reference oscillators
@@ -1036,7 +1036,7 @@ The frequency search bin size is a function of the desired peak magnitude loss (
due to the frequency mismatch and integration time period. This means with larger frequency bands,
it becomes harder to identify the correlation peaks required to obtain the GPS data, described in section \ref{sec:CAdemod}.
% The frequency search bin size can be estimated using the frequency
-% mimsmatch loss \textit{sinc} function given in equation \eqref{eq:mistunigLoss} \citep{implSoftGPSRec},
+% mismatch loss \textit{sinc} function given in equation \eqref{eq:mistunigLoss} \citep{implSoftGPSRec},
% \citep[Chapter 6]{diggelen2009a-gps},
% where $\Delta f$ is the frequency mismatch in $\mathrm{Hz}$,
% in other words it represents the difference
@@ -1048,7 +1048,7 @@ it becomes harder to identify the correlation peaks required to obtain the GPS d
% \label{eq:mistunigLoss}
% D_{F} = \left\vert \frac{\sin(\pi \Delta fT_{ci})}{\pi \Delta fT_{ci}} \right\vert
% \end{equation}
-% The frequency mimsmatch loss sinc function, $D_{F}$, is evaluated in dB,
+% The frequency mismatch loss sinc function, $D_{F}$, is evaluated in dB,
% therefore for a loss of $\approx 0.98 \,\mathrm{dB}$, the frequency mismatch ought to be
% $\Delta f = 250\, \mathrm{Hz}$,
% due to the fact that the maximum loss shall occur when the frequency is differing
@@ -1067,7 +1067,7 @@ The peak implies the correct Doppler frequency and code delay have been found. I
\ref{img:prnSearchSpace3d} smaller frequency bins have been used so that the concept
becomes understandable to the reader. The speed of searching the 2D search space (finding the peak)
depends on the complexity and strategy of the implemented algorithm \citep[Chapter 6]{9780817643904}. In the worst case,
-there are in total 102300 conbinations in the search space,
+there are in total 102300 combinations in the search space,
this can be derived from equation \eqref{eq:totalSearch}.
\begin{equation}
\label{eq:totalSearch}
@@ -1114,12 +1114,12 @@ to estimate the rough position of the satellites, therefore the Doppler effects
roughly estimated. As a consequence of the known Doppler effect, the frequency bins to
search through to obtain the correlation peak are this time limited \citep[Chapter 3]{diggelen2009a-gps}.
Hot start works in the same manner as warm start however, the ephemeris data and time data are precisely
-known (time is known in accuracy of submilliseconds). The process of finding user's position is explained
+known (time is known in accuracy of sub-milliseconds). The process of finding user's position is explained
in detail in appendix section \ref{sec:distanceAndPosition}.
\section{Assisted GPS in wireless networks}
\label{sec:agps}
-In the following paragraphs Assisted GPS (AGPS) shall be presented and how it works.
+In the following paragraphs Assisted-GPS (AGPS) shall be presented and how it works.
AGPS receivers work on the equivalent idea as warm/hot start on GPS receivers.
Instead of loading the recently saved data from the EEPROM, an external
information transfer medium is used to deliver the equivalent type of information that are known
@@ -1127,15 +1127,14 @@ at the warm/hot start \citep{755159}, \citep{901174}, \citep{springerlink:10.100
In this work, the external transfer medium is air and the information are transferred using electromagnetic
waves. The existing GSM interface was utilised for the purpose of delivering the data to the smart phone
with an AGPS receiver. The basic scenario can be seen in figure \ref{img:agpsPrinciple}. The BTS station
-is connected to the Global Navigation Satellite System (GNSS) server, which is directly
-connected to the GPS reference station. The GPS reference station delivers the GNSS server exact time stamps,
-approximate location, satellite health as well as clock corrections, ionospheric and UTC model, almanac and ephemeris data (data transmitted
-by the GPS satellite)
+is connected to the GPS reference station. The GPS reference station delivers the GPS data: exact time stamps;
+approximate location; satellite health as well as clock corrections; ionospheric and UTC model; almanac and
+ephemeris data (data transmitted by the GPS satellites). These data are then transmitted to the MS with a position request.
\citep{springerlink:10.1007/s10291-002-0028-0}.
-\begin{figure}[ht!]
+\begin{figure}[hb!]
\centering
\includegraphics[scale=0.50]{img/A-GPS.pdf}
- \caption{Basic AGPS principle}
+ \caption{Basic AGPS principle.}
\label{img:agpsPrinciple}
\end{figure}
@@ -1153,7 +1152,7 @@ and to generate a location fix \citep{springerlink:10.1007/s10291-002-0028-0}.
The bit error rate associated with gathering and decoding data dramatically decreases since the acquired signals
can be attenuated by $10$ to $20\, \mathrm{dB}$ indoors \citep{springerlink:10.1007/s10291-002-0028-0} of the nominal
$-130 \,\mathrm{dB}$ on a $3\, dBi$ ``linearly polarized user receiving antenna\footnote{3 dBi antenna indicates
-an antenna with a gain of $3\, \mathrm{dB}$ with respect to an isotropic (omnidirectional) antenna
+an antenna with a gain of $3\, \mathrm{dB}$ with respect to an isotropic (omni-directional) antenna
\citep[Chapter 2]{diggelen2009a-gps}.} (located near ground) at worst normal orientation''
\citep{GPS-Interface-Specification}.
@@ -1207,19 +1206,19 @@ developed by the request of government and rescue organizations to fulfill the w
standard in the US, each mobile user had to be located within a range of 300 m in 95\% of cases and
within 100 m in 67\% of cases \citep{E911Accuracy}. The RRLP protocol supports three positioning
techniques: E-OTD, UL-TDOA and AGPS \citep{3GPPTS03.71}.
-The LCS process can be divided into two seperate stages, signal measurements and
+The LCS process can be divided into two separate stages, signal measurements and
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}.
+and the stand-alone handset, in this case the MS \citep[Chapter 5]{harper2010server-side}.
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
channel has to be initialized to the MS, this connection can not be seen by the MS user\footnote{However,
-it is possible to take into consideration that something is going on the cell phone if the MSs battery
+it is possible to take into consideration that something is going on the cell phone if the MS' battery
is drained faster because an active RF connection drains the battery faster than a passive MS
connected to the GSM network.}.
@@ -1233,11 +1232,11 @@ connected to the GSM network.}.
\end{figure}
Data sent inside of a protocol are called Protocol Data Unit (PDU). On different
-layer levels PDU's may take a different shape and size because of the encapsulation
+layer levels PDUs may take a different shape and size because of the encapsulation
or splitting \citep{kozierok2005the} \citep{stevens1994tcp/ip}.
-In RRLP the PDU's sent from the SMLC are not allowed be greater than 244 bytes\footnote{Bytes of 8 bits!} \citep{04.31V8.18.0}.
+In RRLP the PDUs sent from the SMLC are not allowed be greater than 244 bytes\footnote{Bytes of 8 bits!} \citep{04.31V8.18.0}.
Although the standard defines that larger packets ought to be split into smaller pieces in lower layers, in this work the
-rule of 244 bytes has been obeyed due to crashing of the GSM operating software (OpenBSC), thus each PDU packet was not greater
+rule of 244 bytes has been obeyed due to crashing of the GSM operating software, thus each PDU packet was not greater
than 211 bytes. In the RRLP standard terms, the messages are entitled
as \textit{components} and fields in the messages (components) are labeled as \textit{information elements} (IE) \citep{04.31V8.18.0}.
The SMLC may send only the request for the position of the MS or it may assist the MS with assistance data
@@ -1263,7 +1262,7 @@ Abstract Syntax Notation One (ASN.1) in the technical specifications 3GPP 04.31
and ETSI TS 144 031 \citep{49.031V8.1.0} \citep{ETSITS144031}. ASN.1 is a conventional notation
for denoting the abstract syntax of data used inside of protocols or data
structures \citep[Chapter 8]{sharp2008principles} \citep{ITU-TX.680}. In other words, using ASN.1 it is possible
-to describe data in an indepedent representation of programming languages in which a protocol is implemented.
+to describe data in an independent representation of programming languages in which a protocol is implemented.
In this section, only some of the mostly important and used parts of the RRLP protocol
inside of the thesis shall be presented, more details can be found in the
technical specifications \citep{49.031V8.1.0} \citep{ETSITS144031}. It is important to understand the meaning
@@ -1300,7 +1299,7 @@ specifies the reference number of the request and is used for the purpose of ide
the response from the MS. It can take any value between 0 and 7.
\newpage
\begin{lstlisting}[label=lst:RRLP,
-caption={\textbf{Structure of the RRLP message in ASN.1}},
+caption={\textbf{Structure of the RRLP message in ASN.1.}},
backgroundcolor=\color{light-gray},
basicstyle={\scriptsize\ttfamily},
escapechar=@,
@@ -1357,7 +1356,7 @@ the position (time duration) and how many position estimations it is allowed to
If it is allowed to perform more position estimations then all of them will be included in the returned response.
\newpage
\begin{lstlisting}[label=lst:RRLPReq,
-caption={\textbf{Structure of the RRLP request in ASN.1}},
+caption={\textbf{Structure of the RRLP request in ASN.1.}},
backgroundcolor=\color{light-gray},
basicstyle=\scriptsize\ttfamily]
-- Measurement Position request component
@@ -1377,15 +1376,15 @@ MsrPosition-Req ::= SEQUENCE {
\textbf{methodType} defines where the position estimation calculation will be executed.
Does it solely take place on the MS (\textit{msBased}), on the server\footnote{With server
-the BTS location is ment!} only (\textit{msAssisted}),
-or one method is prefered over the other depending if the MS can execute the prefered one method
+the BTS location is meant!} only (\textit{msAssisted}),
+or one method is preferred over the other depending if the MS can execute the preferred one method
(\textit{msBasedPref} or \textit{msAssistedPref}). The uncertainty of the accuracy
of the estimated position is only optional if the chosen method is \textit{msAssisted},
otherwise it must be included in the request message. This uncertainty of the accuracy, is an integer
number and defines how certain the accuracy of the returned position has to be. It can be calculated
using the equation \eqref{eq:uncerAccuracy}, where $K$ is the seven bit integer number
and $r$ is the accuracy uncertainty in meters \citep{3gppequations}. The next three parameters
-to be defined are the position estimation technique (GPS, E-OTD or one of the two prefered by the MS),
+to be defined are the position estimation technique (GPS, E-OTD or one of the two preferred by the MS),
the position measurement time and how many measurements the MS has to report back to the SMLC.
Since in this thesis the author exploits the AGPS method, GPS is chosen for \textbf{PositionMethod}.
\textbf{MeasureResponseTime} is a three bit integer value that corresponds to the time period the MS is allowed
@@ -1409,7 +1408,7 @@ MeasureResponseTimeBitValue=\frac{ln(N)}{ln(2)}
\end{equation}
\newpage
\begin{lstlisting}[label=lst:RRLPReqData,
-caption={\textbf{Structure of the data types from RRLP request in ASN.1}},
+caption={\textbf{Structure of the data types from RRLP request in ASN.1.}},
backgroundcolor=\color{light-gray},
basicstyle=\scriptsize\ttfamily]
-- Position instructions
@@ -1473,11 +1472,11 @@ colors with the intention to recognize easier the different variables in ASN.1 n
The six red zeros define what type of data will be included in the current RRLP packet.
This will become obvious by looking at the listing \ref{lst:RRLPReqPER}. On the left side of listing
\ref{lst:RRLPReqPER} one can see the PER notation, whereas on the right side is the ASN.1 notation.
-After the concationation it can be converted to the desired notation system (binary, hexadecimal, etc.).
+After the concatenation it can be converted to the desired notation system (binary, hexadecimal, etc.).
In this particular example, the RRLP request, can be represented in hexadecimal notation:
\textbf{400178F8}. This RRLP message (packet) is transmitted to the MS via the opened SDCCH channel.
However, before sending this request the assistance data can be sent. In the
-folowing section \ref{sec:rrlpassistance} more details of how assistance data are sent shall be provided.
+following section \ref{sec:rrlpassistance} more details of how assistance data are sent shall be provided.
\begin{figure}[ht!]
\centering
@@ -1487,7 +1486,7 @@ folowing section \ref{sec:rrlpassistance} more details of how assistance data ar
\end{figure}
\begin{lstlisting}[label=lst:RRLPReqPER,
-caption={\textbf{Encoding an RRLP request from ASN.1 to PER}},
+caption={\textbf{Encoding an RRLP request from ASN.1 to PER.}},
backgroundcolor=\color{light-gray},
escapechar=@,
basicstyle=\scriptsize\ttfamily]
@@ -1532,7 +1531,7 @@ packet, one has to specify what type of assistance information is included in th
assistance packets.
In this thesis, as assistance data, only the almanac, ephemeris, UTC model, ionospheric
model and reference location are transmitted to the MS. There are also other assistance
-data like differential GPS corrections (DGPS), real time integrity, acquisition assistance
+data like Differential GPS corrections (DGPS), real time integrity, acquisition assistance
and reference time but none of these were available to the author, so they were avoided.
The reasons for not including them are of cost and complexity nature.
@@ -1573,7 +1572,7 @@ With the reference location, one sends also the altitude and uncertainty of the
data. As a consequence the AGPS receiver can limit the time and frequency search space even further.
The ionospheric model includes data for correcting errors introduced by the radio wave transmission through
the ionosphere \citep[Chapter 4]{harper2010server-side}. Ionosphere data are not satellite dependent thus they
-are not sent for each satellite seperately but only once since they are valid for
+are not sent for each satellite separately but only once since they are valid for
all satellites \citep[Chapter 4]{harper2010server-side}. Ephemeris data in RRLP terminology are named as navigation data.
Ephemeris data contain more precise and accurate orbital information of the satellites.
If the reader is interested in the exact description of the transmitted assistance data,
@@ -1581,7 +1580,7 @@ they can be seen in the appendix, in following tables \ref{tbl:utcModel}, \ref{t
\ref{tbl:almanacMessage} and \ref{tbl:ionoModel}.
\begin{lstlisting}[label=lst:GPSAssisData,
-caption={\textbf{Structure of data types of GPS assistance data in ASN.1}},
+caption={\textbf{Structure of data types of GPS assistance data in ASN.1.}},
backgroundcolor=\color{light-gray},
basicstyle=\scriptsize\ttfamily]
-- Control header of the GPS assistance data
@@ -1613,7 +1612,7 @@ reference location, DGPS corrections, navigation model, ionospheric model, UTC m
acquisition assistance and real time integrity (all marked with blue color in
listing \ref{lst:RRLPAssisPER}).
\begin{lstlisting}[label=lst:RRLPAssisPER,
-caption={\textbf{Encoding reference location from ASN.1 to PER}},
+caption={\textbf{Encoding reference location from ASN.1 to PER.}},
backgroundcolor=\color{light-gray},
basicstyle=\scriptsize\ttfamily,
escapechar=@,
@@ -1754,7 +1753,7 @@ The MS may include more information on the error if it can identify the error (n
In case the MS does support more information, an optional IE \textit{additionalAssistanceData} bit will be set
(marked in cyan).
\begin{lstlisting}[label=lst:RRLPRespError,
-caption={\textbf{Decoding an error RRLP response from Samsung Galaxy S3}},
+caption={\textbf{Decoding an error RRLP response from Samsung Galaxy S3.}},
backgroundcolor=\color{light-gray},
basicstyle=\scriptsize\ttfamily,
escapechar=@,
@@ -1804,7 +1803,7 @@ the IE \textit{gpsAssistanceData} bit, as shown in listing \ref{lst:RRLPRespErro
(marked with magenta color). If this bit was set, the length of the IE for requested missing assistance
data will be exactly specified as well as what assistance data are missing (marked in orange color).
\begin{lstlisting}[label=lst:RRLPPosError,
-caption={\textbf{Possible location error reasons}},
+caption={\textbf{Possible location error reasons.}},
backgroundcolor=\color{light-gray},
basicstyle=\scriptsize\ttfamily]
LocErrorReason ::= ENUMERATED {
@@ -1835,7 +1834,7 @@ assistance data (marked in orange color). Information of missing assistance data
in figure \ref{img:RequestedGPSAss} \citep{49.031V8.1.0}. If one of these bits from A to K is set,
the MS requires more assistance data. The meaning of the bits in figure \ref{img:RequestedGPSAss}
are explained in table \ref{tbl:RRLPReqAss}. In this particular example, the first two bytes are: \textbf{E800},
-indicating acquisition assistance, reference time, reference location and the navigation model are requsted
+indicating acquisition assistance, reference time, reference location and the navigation model are requested
by the MS as assistance data.
The next RRLP response example, shown in listing \ref{lst:RRLPRespSucc}, is
@@ -1843,7 +1842,7 @@ a response with a successfully estimated position! In the second byte, two mutua
contain the information if the response was successful and contains the location information, \textit{locationInfo} bit must
be set and \textit{locationError} must be zero (both marked in red color in listing \ref{lst:RRLPRespSucc}).
\begin{lstlisting}[label=lst:RRLPRespSucc,
-caption={\textbf{Decoding a successful RRLP response from iPhone 3GS}},
+caption={\textbf{Decoding a successful RRLP response from iPhone 3GS.}},
backgroundcolor=\color{light-gray},
basicstyle=\scriptsize\ttfamily,
escapechar=@,
@@ -1884,10 +1883,10 @@ B6 1....... FixType = 1 :threeDFix
\end{lstlisting}
If the IE \textit{locationInfo} bit is set and \textit{locationError} bit is zero, then the position of the MS is
included in the response. Aside from the position information, the time when the position measurement
-was performed is included as well however, only the least significant bits in the range of miliseconds. The
+was performed is included as well however, only the least significant bits in the range of milliseconds. The
most significant bits ought to be derived by the SMLC using the GSM frame number, included in the IE \textit{refFrame}.
In this thesis this is not known and used. \textit{refFrame} contains the GSM frame number as observed by
-the MS \citep{49.031V8.1.0}. The time of miliseconds can be found in the IE \textit{gpsTOW}. The included time is
+the MS \citep{49.031V8.1.0}. The time of milliseconds can be found in the IE \textit{gpsTOW}. The included time is
not in UTC format and would require additional conversions.
The elements of \textit{locationInfo} can be seen in listing \ref{lst:RRLPLocInfo}. The IE \textit{fixType} contains
the information if the performed measurement was 2D or 3D GPS fix. An 2D fix is when only 3 GPS satellites are
@@ -1918,7 +1917,7 @@ $F$&Ionospheric model requested
\end {tabular}
\end {table}
\begin{lstlisting}[label=lst:RRLPLocInfo,
-caption={\textbf{Structure of data types of location info data in ASN.1}},
+caption={\textbf{Structure of data types of location info data in ASN.1.}},
backgroundcolor=\color{light-gray},
basicstyle=\scriptsize\ttfamily,
escapechar=@]
@@ -2011,7 +2010,7 @@ radio wave signal. The basic idea is to use the fast performance
of the CPU inside the computer to do the signal processing while the
SDR hardware itself performs only the physical radio communication like
emitting and receiving radio waves. Alternatively to the
-dedicated hardware, SDR's are cheaper and can be
+dedicated hardware, SDRs are cheaper and can be
programmed to perform various functions e.g. an FM radio,
a GPS receiver, GSM and etc. All of the stated ``emulated devices''
employ different modulation/demodulation techniques and
@@ -2031,7 +2030,7 @@ strange behaviour had been discovered. Occasionally the smart phones ($iPhones$
did not detect the created GSM network with OpenBTS, i.e. the network could not be found in
the search menu where all GSM networks in range are shown.
The reason for this strange phenomenon may be found
-in the unstable operation of the cheap clock oscillator. However, the clock's unstability
+in the unstable operation of the cheap clock oscillator. However, the clock's instability
issue can not be confirmed by the author due to the missing hardware equipment to measure
the actual frequency and its deviation. Nevertheless, these findings
were consistent with the results of the OpenBTS developers
@@ -2047,7 +2046,7 @@ issues.
The deployed RRLP module for OpenBTS was written by Kurtis Heimerl in two different programming
languages, Erlang and Common Gateway Interface (CGI)\footnote{Kurtis Heimerl's code can be
-found on \url{https://github.com/ttsou/RRLP}.}. The new GMS system configuration with the RRLP module
+found on \url{https://github.com/ttsou/RRLP}.}. The new GSM system configuration with the RRLP module
in OpenBTS was examined. The first observation
and finding was that not a single smart phone could connect to the GSM network.
The log files contained information why the smart phones could not connect to the GSM network.
@@ -2088,7 +2087,7 @@ shall be given followed by the testbed setup configuration with connection schem
\subsection{GSM BTS - nanoBTS}
In recent years, there has been an increasing interest in the deployment of
private cellular networks in remote areas which led to
-the devolopment of diverse ``low-cost'' GSM hardware solutions. According to
+the development 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, aviation and public spaces''.
@@ -2099,7 +2098,7 @@ Federal Network Agency (German: $Bundesnetzagentur$). The transmission frequenci
range between 1805-1880 MHz, with 200 kHz channel spacing and the maximum
output power of +23 dBm ($\approx$200 mW), whereas the receiving frequencies
lie in the range between 1710-1785 MHz \citep{nanoGSM2007brochure}.
-The ethernet cable with power supply is required to power the BTS and
+The Ethernet cable with power supply is required to power the BTS and
to connect its operating software (OpenBSC). The other ports are used to
extend the GSM network performance operation but are not relevant to the
work presented in this thesis.
@@ -2113,7 +2112,7 @@ work presented in this thesis.
To determine the working state of the nanoBTS, an indicator status LED is located on the
left side of the five ports area. After the nanoBTS is connected to the power supply
-with the ethernet cable, it changes its color and blink speed according to the state
+with the Ethernet cable, it changes its color and blink speed according to the state
it is in. The states are given in appendix and can be seen in the table given in
\ref{tbl:LEDStatus} \citep{installnanoBTS}. One of the key limitations of gathering more
technical data and the critical aspect of this description lies in the fact
@@ -2131,11 +2130,11 @@ The GPS receiver was used as an indicator of whether there is any GPS signal in
\subsection{Testbed setup configuration}
\label{sec:hardwareConfig}
%At least 4 network cables with RJ45 connectors were required
-%and one switch or hub connected to the internet. It is important to carefully
-%proceed with the cabling of the nanoBTS and the ethernet switch or hub, since wrong
+%and one switch or hub connected to the Internet. It is important to carefully
+%proceed with the cabling of the nanoBTS and the Ethernet switch or hub, since wrong
%wiring with the power supply unit (PSU) could damage one of the devices.
In Figure \ref{img:connectionDiagram}, the junction points are label according
-to the used configuration setting. %The ethernet cables between the switch/hub,
+to the used configuration setting. %The Ethernet cables between the switch/hub,
%PSU and nanoBTS should not be longer than 100 m \citep{installnanoBTS}.
Author's test system operated on the ARFCN 877 channel.
ARFCN 877 corresponds to the uplink frequency of 1,783.2 MHz and a downlink
@@ -2197,7 +2196,7 @@ The RRLP data generated by Heimerl's application
did not produce valid assistance data. In order to publish the RRLP assistance
data generator as open source to be extended further or ported to another
programming language, it was required to be written in a programming language
-understandale to a wider audience. Since the RRLP data generator application
+understandable to a wider audience. Since the RRLP data generator application
is independent of the GSM operating software, it was sound to write the
RRLP assistance data generator in C++. Another reason why C++ was
taken is due to the fact that OpenBSC was written in C and OpenBTS in C++.
@@ -2215,7 +2214,7 @@ and ephemeris files, downloaded from the Navigation Center of the US Coast Guard
and Trimble, assistance data for 32 different GPS satellites are present.
Contrary to expectations, Heimerl's code produced RRLP assistance
data valid for only one satellite. The rest of the assistance
-data were duplicats of the assistance data for one satellite.
+data were duplicates of the assistance data for one satellite.
At this stage, it was important to have a fully working RRLP assistance data
generator. This generator would be subsequently used to examine the RRLP
protocol once OpenBSC was modified to open a data channel for transmitting
@@ -2362,7 +2361,7 @@ int response = gsm48_send_rr_app_info(conn, 0x00, AlmanacPackets[packNum].length
%Author's test system operated on the ARFCN 877 channel. ARFCN (Absolute Radio
-%Frequency Channel Number) defines the uplink and downlink channel frequency insdide
+%Frequency Channel Number) defines the uplink and downlink channel frequency inside
%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
@@ -2458,7 +2457,7 @@ had used the assistance data to estimate its position. Otherwise the $iPhone$ $3
when only an RRLP position request was sent. Interestingly, the $G1$ did not provide any results
when the ephemeris data have been delivered. These findings suggest that the AGPS receiver in
$G1$ may suffer from not knowing how to employ the ephemeris data. This might be due to the fact that $G1$ is
-one of the first ``real'' smart phones on the market. Afterwards, evedince for smart phones not being able to utilise
+one of the first ``real'' smart phones on the market. Afterwards, evidence for smart phones not being able to utilise
any of the assistance data, will be provided for other smart phones older than the $G1$.
\begin{figure}
@@ -2525,7 +2524,7 @@ statements have to be considered with ambiguity. Another contrary to expectation
were the results with two Nokia ``smart phone'' models $E71$ and $N95$. The
results were only delivered when an RRLP request was sent without any assistance
data. Although it was stated in their specifications that both cell phones are
-equiped with an AGPS receiver \citep{nokiae71} \citep{nokian95}.
+equipped with an AGPS receiver \citep{nokiae71} \citep{nokian95}.
However, RRLP requests with assistance data did
not produce any output from these smart phones. The reason for this behaviour is
not completely obvious but it might be due to the fact these are older models
@@ -2555,7 +2554,7 @@ windows exist right after the smart phones have successfully delivered their pos
in Test room 2. This test did not deliver any position but only time-outs
or errors containing information that no satellites are visible.
This test confirmed that the smart phones are always performing a
-postion estimation at the moment when an RRLP request is sent to the MS.
+position estimation at the moment when an RRLP request is sent to the MS.
The last test has been carried out outside of the computer pool building.
This test was conducted to confirm the argument that precision of the estimated
@@ -2578,7 +2577,7 @@ $Defy$&No&No&No&No response (time-out) \\\midrule
$iPhone$ $4$&No&No&No&Reference time, Navigation Model,\\
&&&&Reference Location\\\midrule
$iPhone$ $3GS$&Yes&Yes&No&/\\\midrule
-$G1$&No&Yes&Only occasionallys&/\\\midrule
+$G1$&No&Yes&Only occasionally&/\\\midrule
$Galaxy$ $S2$&No&No&No&Acquisition Assistance\\\midrule
$Galaxy$ $S3$&No&No&No&Reference Location, Reference Time,\\
&&&&Acquisition Assistance, Navigation Model\\\midrule
@@ -2733,7 +2732,7 @@ to take another route.
%The produced RRLP software and obtained results may be used to develop new strategies aimed at
%protecting privacy of cell phone users.
-This thesis investigated how difficult it is to integrate mobile assisted GPS localization in GSM
+This thesis investigated the possibility to integrate mobile assisted GPS localization in GSM
networks on undedicated and dedicated GSM hardware. The aim of this work was to implement the
``first'' working open source RRLP
implementation in GSM networks, as well as to determine and evaluate the limits of this localization
@@ -2766,3 +2765,5 @@ that this is only a small revealed section of a larger hidden issue! A future st
assistance data being provided to the cell phones would be very interesting. The produced RRLP
software and obtained results may be used to develop new strategies aimed at protecting the privacy
of cell phone users.
+
+%\addcontentsline{toc}{chapter}{Dictionary of acronyms} \ No newline at end of file