From 6bf0cdc22b407ccba23653e74ab175a331179177 Mon Sep 17 00:00:00 2001 From: Refik Hadzialic Date: Wed, 15 Aug 2012 18:52:49 +0200 Subject: GSM --- vorlagen/thesis/maindoc.pdf | Bin 6899134 -> 6904567 bytes vorlagen/thesis/src/bib/literatur.bib | 8 ++++++ vorlagen/thesis/src/kapitel_x.tex | 48 +++++++++++++++++++++++++++++++--- vorlagen/thesis/src/maindoc.lof | 2 +- 4 files changed, 54 insertions(+), 4 deletions(-) diff --git a/vorlagen/thesis/maindoc.pdf b/vorlagen/thesis/maindoc.pdf index 8130dd7..791303c 100644 Binary files a/vorlagen/thesis/maindoc.pdf and b/vorlagen/thesis/maindoc.pdf differ diff --git a/vorlagen/thesis/src/bib/literatur.bib b/vorlagen/thesis/src/bib/literatur.bib index 393dddb..6569beb 100644 --- a/vorlagen/thesis/src/bib/literatur.bib +++ b/vorlagen/thesis/src/bib/literatur.bib @@ -680,4 +680,12 @@ ISSN={0018-9251},} Publisher = {CRC Press}, Year = {2003}, ISBN = {0824740408} +} + +@book{0470742984, + Author = {Jie Zhang and Guillaume de la Roche}, + Title = {Femtocells: Technologies and Deployment}, + Publisher = {Wiley}, + Year = {2010}, + ISBN = {0470742984} } \ No newline at end of file diff --git a/vorlagen/thesis/src/kapitel_x.tex b/vorlagen/thesis/src/kapitel_x.tex index ba5fcdd..28a5af9 100644 --- a/vorlagen/thesis/src/kapitel_x.tex +++ b/vorlagen/thesis/src/kapitel_x.tex @@ -1435,7 +1435,7 @@ channel but in different time slots. Using this technique the voice throughput i of users can be served at the ``same'' time, i.e. the capacity of parallely speaking GSM users is increased. TDMA was employed because the voice could be compressed with Linear Predictive Coding (LPC) without the human noting a difference in the call quality \citep{0824740408}. By taking advantage of LPC, instead of the 64 kbps required for transmission of voice -it was possible to compress the voice without losing much of the call quality into 6.5 kbps for half rate and 13 kbps for +it was possible to compress the voice without losing much of the call quality into 8 kbps for half rate and 16 kbps for full rate\footnote{Human speech has a frequency bandwidth between 0 and 4000 Hz \citep{humanFreq}. 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 @@ -1461,23 +1461,65 @@ in GSM is known as a burst. Every TDMA frame is assigned a unique integer number every 3h:28m:53s:760ms, also known as \textit{hyperframe} \citep[Chapter 7]{0890064717}. In the hierarchy pyramid, a layer lower of the hyperframe is the \textit{superframe}. There are two types of superframes, consisting of two types of \textit{multiframes}, differing in their length \citep[Chapter 7]{0890064717}. The relations can be seen in figure -\ref{img:GSMHierarchy} with their duration periods. +\ref{img:GSMHierarchy} with their duration periods. The multiframe with 26 TDMA frames carries only traffic channels (TCH) and associated +control channels (CCH). The other multiframe type, with 51 TDMA frames carries solely signaling data. This hierarchy constrain +was defined due to internal synchronization and cyphering between the MS and the Base Transceiver Station (BTS) +\citep[Chapter 7]{0890064717}. \begin{figure}[ht!] \centering \includegraphics[scale=0.70]{img/GSMHierarchy.pdf} - \caption{Hierarchy of the frames in GSM.} + \caption{Hierarchy of the GSM frames.} \label{img:GSMHierarchy} \end{figure} +BTS is the first hardware unit the cell phone is communicating with over the air interface +and provides a ``physical'' connection with the cell phone \citep[Chapter 3]{0890064717}. This physical connection between the +BTS and the cell phone is the \textit{$U_m$ interface}, as shown in figure \ref{img:GSMBig}. A BTS can serve up +to seven users on one frequency since one out of eight time slot is used for broadcasting of signaling and system information, +known as the broadcast control channel (BCCH). By sectorizing BTSs with different frequencies the number of seven mobile users +can be increas. BTS consists of a RF tranceiver, 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 the TDMA frames, with an accuracy of at least $\pm$5 ppm \citep{dennis}. +Modulator/demodulator main function is the modulation and demodulation of the received and transmitted signals. +The transmission from the cell phone to the BTS is shifted for 3 time slots compared to the reception +of the signal from the BTS\footnote{Timing advance factor is added to the three time slots.} +\citep[Chapter 7]{0890064717} \citep{konrad} \citep{}. \begin{figure}[ht!] \centering \includegraphics[scale=0.50]{img/GSMBig.pdf} \caption{Basic GSM network block diagram.} \label{img:GSMBig} \end{figure} + +One or more BTSs are connected to the Base Station Controller (BSC). The main task of the BSC is to control the radio +resources of the connected BTSs such as assigning radio channels to different BTS, frequency hopping in case of an handover +and controlling the power levels within channel \citep[Chapter 4]{0470742984} \citep{konrad} \citep[Chapter 3]{0890064717}. +BSC is connected to the Transcoding Rate and Adaptation Unit (TRAU). 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. + +The next subsystem block is the Network Switching Subsystem (NSS), as it can be seen on figure \ref{img:GSMBig}, on right +side inside of the gray dashed line rectangle. + \section{SDCCH Channel} + + + + + + + + + + + + + \chapter{Radio Resource Location Protocol} This chapter shall focus on the Radio Resource Location Protocol (RRLP) and a description how it works inside of the GSM network shall be given. RRLP is a protocol from the family of Location Services (LCS) diff --git a/vorlagen/thesis/src/maindoc.lof b/vorlagen/thesis/src/maindoc.lof index 401df80..bcdb2fe 100644 --- a/vorlagen/thesis/src/maindoc.lof +++ b/vorlagen/thesis/src/maindoc.lof @@ -26,7 +26,7 @@ \addvspace {10\p@ } \contentsline {figure}{\numberline {3.1}{\ignorespaces Frequency ranges of uplink and downlink channels in the GSM900 band. Each box represents a frequency band (channel).\relax }}{39}{figure.caption.29} \contentsline {figure}{\numberline {3.2}{\ignorespaces Each frequency channel is split into 8 time slots. More GSM users can be served at the ``same'' time.\relax }}{40}{figure.caption.30} -\contentsline {figure}{\numberline {3.3}{\ignorespaces Hierarchy of the frames in GSM.\relax }}{40}{figure.caption.31} +\contentsline {figure}{\numberline {3.3}{\ignorespaces Hierarchy of the GSM frames.\relax }}{40}{figure.caption.31} \contentsline {figure}{\numberline {3.4}{\ignorespaces Basic GSM network block diagram.\relax }}{41}{figure.caption.32} \addvspace {10\p@ } \contentsline {figure}{\numberline {4.1}{\ignorespaces RRLP Request protocol. Assistance data can be sent before the request is made. If the assistance data are sent, their reception acknowledgement is sent as a response from the MS.\relax }}{44}{figure.caption.33} -- cgit v1.2.3-55-g7522