diff --git a/src/thesis/chapters/4_decoding_under_dems.tex b/src/thesis/chapters/4_decoding_under_dems.tex index 2b99789..96e5722 100644 --- a/src/thesis/chapters/4_decoding_under_dems.tex +++ b/src/thesis/chapters/4_decoding_under_dems.tex @@ -376,8 +376,8 @@ explicitly work with the \ac{dem} formalism. % } %%%%%%%%%%%%%%%% -\subsection{Algorithm} -\label{subsec:Algorithm} +\subsection{Window Splitting and Sequential Sliding-Window Decoding} +\label{subsec:Window Splitting and Sequential Sliding-Window Decoding} In this section, we will examine the methodology by which a detector error matrix is divided into overlapping windows. @@ -634,32 +634,31 @@ and after decoding all windows we will therefore have committed all \acp{vn}. \label{fig:vis_rep} \end{figure} -\Cref{fig:vis_rep} illustrates the meaning of the various sets of nodes. - % Syndrome update -\content{Why we need to update the syndrome} -\content{How we update the syndrome} -\content{\textbf{General note}: Mathematical definitions where possible} - -% Complete process - -\content{(?) Proper algorithm definition?} -\content{1. Decode window} -\content{2. Commit VN estimates} -\content{3. Update syndrome} -\content{4. Decode next window} -\content{(?) Explicitly mention we don't reuse existing messages?} - -\content{Double-check all definitions} - -% TODO: Do I need this? -% \content{Possibly go into the fact that current sliding-window -% approaches don't differentiate clearly between the sliding-window -% part and the decoder part. This work aims to extend the -% sliding-window part in a general fashion that is compatible with many -% different decoder parts. Combine this with QUITS modular structure -% for sliding window decoding} +\Cref{fig:vis_rep} illustrates the meaning of the various sets of nodes. +We can also see a particular point we have to be careful about when +moving on to decode the next window. +While the \acp{vn} in $\mathcal{J}_\text{commit}^{(\ell)}$ have no +bearing on the further decoding process, the values commit for the +\acp{vn} in $\mathcal{I}_\text{commit}^{(\ell)}$ do. +This is the case because these \acp{vn} have neighboring \acp{cn} in +the next window. +The part of the detector error matrix $\bm{H}_\text{DEM}$ describing +these connections is +$\bm{H}_\text{overlap}^{(\ell)} = +\left(\bm{H}_\text{DEM}\right)_{\mathcal{J}_\text{overlap}^{(\ell)}, +\mathcal{I}_\text{commit}^{(\ell)}}$. +We have to account for this fact by updating the syndrome $\bm{s}$ +based on the committed bit values. +Specifically, if $\bm{e}_\text{commit}^{(\ell)}$ describes the error +estimates commited after decoding window $\ell$, we have to set +\begin{align*} + \bm{s}_{\mathcal{J}_\text{overlap}^{(\ell)}} = + \bm{H}_\text{overlap}^{(\ell)} + \left( \bm{e}_\text{commit}^{(\ell)} \right)^\text{T} + .% +\end{align*} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \section{Warm-Start Sliding-Window Decoding}