Added supplementary slides for choice of gamma, mu and rho

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Andreas Tsouchlos 2023-04-19 00:30:42 +02:00
parent 58ae265fd3
commit 8f3a74ae63
3 changed files with 27 additions and 15 deletions

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@ -76,7 +76,7 @@
@mastersthesis{yanxia_lu_thesis, @mastersthesis{yanxia_lu_thesis,
author = {Lu, Yanxia}, author = {Lu, Yanxia},
title = {Realization of Channel Decoding Using Optimization Techniques}, title = {Realization of Channel Decoding Using Optimization Techniques},
year = {2023}, year = {2022},
type = {Bachelor's Thesis}, type = {Bachelor's Thesis},
institution = {KIT}, institution = {KIT},
} }

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@ -87,7 +87,7 @@ return $\boldsymbol{s}$
+ \underbrace{\sum\nolimits_{j\in\mathcal{J}} g_j\left( \boldsymbol{T}_j\tilde{\boldsymbol{c}} \right) } + \underbrace{\sum\nolimits_{j\in\mathcal{J}} g_j\left( \boldsymbol{T}_j\tilde{\boldsymbol{c}} \right) }
_{\text{Constraints}} \\ _{\text{Constraints}} \\
\text{subject to}\hspace{5mm} & \text{subject to}\hspace{5mm} &
\tilde{\boldsymbol{c}} \in \mathbb{R}^n \tilde{\boldsymbol{c}} \in \left[ 0, 1 \right]^n
\end{align*} \end{align*}
\begin{genericAlgorithm}[caption={}, label={}, \begin{genericAlgorithm}[caption={}, label={},

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@ -21,7 +21,7 @@ For example:%
% %
\begin{align*} \begin{align*}
x \in \left\{ -1, 1 \right\} &\to \tilde{x} \in \mathbb{R}\\ x \in \left\{ -1, 1 \right\} &\to \tilde{x} \in \mathbb{R}\\
c \in \mathbb{F}_2 &\to \tilde{c} \in \left[ 0, 1 \right] c \in \mathbb{F}_2 &\to \tilde{c} \in \left[ 0, 1 \right] \subseteq \mathbb{R}
.\end{align*} .\end{align*}
% %
Additionally, a shorthand notation will be used to denote series of indices and series Additionally, a shorthand notation will be used to denote series of indices and series
@ -29,9 +29,10 @@ of indexed variables:%
% %
\begin{align*} \begin{align*}
\left[ m:n \right] &:= \left\{ m, m+1, \ldots, n-1, n \right\}, \left[ m:n \right] &:= \left\{ m, m+1, \ldots, n-1, n \right\},
\hspace{5mm} m,n\in\mathbb{Z}\\ \hspace{5mm} m < n, \hspace{2mm} m,n\in\mathbb{Z}\\
x_{\left[ m:n \right] } &:= \left\{ x_m, x_{m+1}, \ldots, x_{n-1}, x_n \right\} x_{\left[ m:n \right] } &:= \left\{ x_m, x_{m+1}, \ldots, x_{n-1}, x_n \right\}
.\end{align*} .\end{align*}
\todo{Not really slicing. How should it be denoted?}
% %
In order to designate elemen-twise operations, in particular the \textit{Hadamard product} In order to designate elemen-twise operations, in particular the \textit{Hadamard product}
and the \textit{Hadamard power}, the operator $\circ$ will be used:% and the \textit{Hadamard power}, the operator $\circ$ will be used:%
@ -50,16 +51,17 @@ and the \textit{Hadamard power}, the operator $\circ$ will be used:%
\section{Preliminaries: Channel Model and Modulation} \section{Preliminaries: Channel Model and Modulation}
\label{sec:theo:Preliminaries: Channel Model and Modulation} \label{sec:theo:Preliminaries: Channel Model and Modulation}
In order to transmit a bit-word $\boldsymbol{c}$ of length $n$ over a channel, In order to transmit a bit-word $\boldsymbol{c} \in \mathbb{F}_2^n$ of length
it has to be mapped onto a symbol $\boldsymbol{x}$ that can be physically $n$ over a channel, it has to be mapped onto a symbol
transmitted. $\boldsymbol{x} \in \mathbb{R}^n$ that can be physically transmitted.
This is known as modulation. The modulation scheme chosen here is \ac{BPSK}:% This is known as modulation. The modulation scheme chosen here is \ac{BPSK}:%
% %
\begin{align*} \begin{align*}
\boldsymbol{x} = \left( -1 \right)^{\boldsymbol{c}} \boldsymbol{x} = 1 - 2\boldsymbol{c}
.\end{align*} .\end{align*}
% %
The symbol that reaches the receiver, $\boldsymbol{y}$, is distorted by the channel. The transmitted symbol is distorted by the channel and denoted by
$\boldsymbol{y} \in \mathbb{R}^n$.
This distortion is described by the channel model, which in the context of This distortion is described by the channel model, which in the context of
this thesis is chosen to be \ac{AWGN}:% this thesis is chosen to be \ac{AWGN}:%
% %
@ -87,7 +89,7 @@ of the channel \cite[Sec. II.B.]{mackay_rediscovery} while having a structure
that allows for very efficient decoding. that allows for very efficient decoding.
The lengths of the data words and codewords are denoted by $k\in\mathbb{N}$ The lengths of the data words and codewords are denoted by $k\in\mathbb{N}$
and $n\in\mathbb{N}$, respectively. and $n\in\mathbb{N}$, respectively, with $k \le n$.
The set of codewords $\mathcal{C} \subset \mathbb{F}_2^n$ of a binary The set of codewords $\mathcal{C} \subset \mathbb{F}_2^n$ of a binary
linear code can be represented using the \textit{parity-check matrix} linear code can be represented using the \textit{parity-check matrix}
$\boldsymbol{H} \in \mathbb{F}_2^{m\times n}$, where $m$ represents $\boldsymbol{H} \in \mathbb{F}_2^{m\times n}$, where $m$ represents
@ -103,14 +105,14 @@ $\boldsymbol{c} \in \mathbb{F}_2^n$ using the \textit{generator matrix}
$\boldsymbol{G} \in \mathbb{F}_2^{k\times n}$:% $\boldsymbol{G} \in \mathbb{F}_2^{k\times n}$:%
% %
\begin{align*} \begin{align*}
\boldsymbol{c} = \boldsymbol{u}^\text{T}\boldsymbol{G} \boldsymbol{c} = \boldsymbol{u}\boldsymbol{G}
.\end{align*} .\end{align*}
% %
After obtaining a codeword from a data word, it is transmitted over a channel After obtaining a codeword from a data word, it is transmitted over a channel
as described in section \ref{sec:theo:Preliminaries: Channel Model and Modulation}. as described in section \ref{sec:theo:Preliminaries: Channel Model and Modulation}.
The received signal $\boldsymbol{y}$ is then decoded to obtain The received signal $\boldsymbol{y}$ is then decoded to obtain
an estimate of the transmitted codeword, $\hat{\boldsymbol{c}}$. an estimate of the transmitted codeword, denoted as $\hat{\boldsymbol{c}}$.
Finally, the encoding procedure is reversed and an estimate of the originally Finally, the encoding procedure is reversed and an estimate of the originally
sent data word, $\hat{\boldsymbol{u}}$, is produced. sent data word, $\hat{\boldsymbol{u}}$, is produced.
The methods examined in this work are all based on \textit{soft-decision} decoding, The methods examined in this work are all based on \textit{soft-decision} decoding,
@ -170,7 +172,17 @@ criterion:%
\right) \right)
.\end{align*}% .\end{align*}%
% %
The \ac{MAP}- and \ac{ML}-criteria are closely connected through
\textit{Bayes' theorem}:%
%
\begin{align*}
\argmax_{c\in\mathcal{C}} p_{\boldsymbol{C} \mid \boldsymbol{Y}}
\left( \boldsymbol{c} \mid \boldsymbol{y} \right)
= TODO
.\end{align*}
%
This has the consequence that if the probability \ldots, the two criteria are
equivalent.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@ -472,8 +484,8 @@ and minimizing $g$ using the proximal operator
\cite[Sec. 4.2]{proximal_algorithms}:% \cite[Sec. 4.2]{proximal_algorithms}:%
% %
\begin{align*} \begin{align*}
\boldsymbol{x} \leftarrow \boldsymbol{x} - \lambda \nabla f\left( \boldsymbol{x} \right) \\ \boldsymbol{x} &\leftarrow \boldsymbol{x} - \lambda \nabla f\left( \boldsymbol{x} \right) \\
\boldsymbol{x} \leftarrow \textbf{prox}_{\lambda g} \left( \boldsymbol{x} \right) \boldsymbol{x} &\leftarrow \textbf{prox}_{\lambda g} \left( \boldsymbol{x} \right)
,\end{align*} ,\end{align*}
% %
Since $g$ is minimized with the proximal operator and is thus not required Since $g$ is minimized with the proximal operator and is thus not required