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| -rw-r--r-- | doc/thesis/chapters/implementation.tex | 12 | ||||
| -rw-r--r-- | doc/thesis/chapters/theory.tex | 9 |
2 files changed, 17 insertions, 4 deletions
diff --git a/doc/thesis/chapters/implementation.tex b/doc/thesis/chapters/implementation.tex index 4518611..9155b2e 100644 --- a/doc/thesis/chapters/implementation.tex +++ b/doc/thesis/chapters/implementation.tex @@ -1,6 +1,6 @@ % vim: set ts=2 sw=2 noet spell: -\chapter{Implementation} +\chapter{Implementation} \label{chp:implementation} \section{Overview} @@ -393,7 +393,7 @@ The numbers of tags used in this case are similar to the number of given values. \SI{5.0}{\micro\second} & \(\SI{-7.0}{\decibel} \approx 0.1995\) \\ \bottomrule \end{tabular} - \caption{Extended Typical Urban model (ETU) ETSI Standard PDP values for multipath fading propagation conditions. \cite{ETSI}. \label{tab:etsi-tap-values}} + \caption{Extended Typical Urban model (ETU) ETSI Standard PDP values for multipath fading propagation conditions \cite{ETSI}. \label{tab:etsi-tap-values}} \end{table} % \begin{figure} @@ -515,4 +515,12 @@ Without those only the amplitudes could be seen in the Plots, with all the noise Simulations with a dynamic fading channel model using PDP values of the Extended Typical Urban model (ETU) of the ETSI standard normative Annex B.2 in \cite{ETSI}. The color gradient represents progression in time. } \end{figure} +\newpage +\begin{figure} + \centering + \input{figures/tikz/qpsk-hardware} + \caption{ + TODO QPSK hardware + } +\end{figure} \restoregeometry diff --git a/doc/thesis/chapters/theory.tex b/doc/thesis/chapters/theory.tex index ceaa649..5df34ef 100644 --- a/doc/thesis/chapters/theory.tex +++ b/doc/thesis/chapters/theory.tex @@ -223,8 +223,13 @@ An intuitive parameter to quantify how dispersive channel is, is to take the tim \end{equation} as is done in \cite{Gallager}. However since in reality some paths get more attenuated than others (\(c_k(t)\) parameters) it also not uncommon to define the delay spread as a weighted mean or even as a statistical second moment (RMS value), where mean tap power \(\expectation\{|c_k(t)|^2\}\) is taken into account \cite{Mathis,Messier}. % More sophisticated definitions of delay spread will be briefly mentioned later in section \ref{sec:statistical-model}. -Another important parameter for quantifying dispersion is \emph{coherence bandwidth}, a measure that is highly related to delay spread but in the frequency domain. % Coherence bandwidth can be be defined as -\skelpar[3] +Another important parameter for quantifying dispersion is \emph{coherence bandwidth}, a measure that is highly related to delay spread but in the frequency domain. Coherence bandwidth, is informally ``how much bandwidth can be used by the signal before it gets distorted (in our case by fading)'' \cite{Messier}. Thus intuitively, this parameter must be related to the delay spread with an inversely proportional relationship since higher delay spread implies more intersymbol interference. And in fact, although there are multiple definitions depending on the context, the coherence bandwidth \(B_c\) can be usually estimated with +\begin{equation} + B_c \approx \frac{1}{T_d}. +\end{equation} + +Finally, another important mean of parametrizing a multipath fading channel is what is called a \emph{power delay profile} (PDP). PDPs are nothing but a list of taps for a FIR model of multipath fading \cite{Mathis}. The weight of each tap in the PDP corresponds to the average channel tap power \(\expectation\{|h_l|^2\}\) (hence the name \emph{power} delay profile) and is usually given in decibel \cite{Mathis,Messier}. An example is shown at the end of chapter \ref{chp:implementation} in \tabref{tab:etsi-tap-values}. + % \subsection{Effects of multipath fading on modulation constellations} % |