%% CHAPTER 06 %%
%% %%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
- \chapter{ Perimeter-based Coverage Optimization to Improve Lifetime in Wireless Sensor Networks}
+ \chapter{ Perimeter-based Coverage Optimization to Improve Lifetime in WSNs}
\label{ch6}
%\emph{Initialize the sensor node and determine it's position and subregion} \;
\If{ $RE_k \geq E_{th}$ }{
- \emph{$s_k.status$ = COMMUNICATION}\;
+ \emph{$s_j.status$ = COMMUNICATION}\;
\emph{Send $INFO()$ packet to other nodes in subregion}\;
\emph{Wait $INFO()$ packet from other nodes in subregion}\;
\emph{Update A.CurrentSize}\;
\emph{LeaderID = Leader election}\;
- \If{$ s_k.ID = LeaderID $}{
- \emph{$s_k.status$ = COMPUTATION}\;
+ \If{$ s_j.ID = LeaderID $}{
+ \emph{$s_j.status$ = COMPUTATION}\;
- \If{$ s_k.ID $ is Not previously selected as a Leader }{
+ \If{$ s_j.ID $ is Not previously selected as a Leader }{
\emph{ Execute the perimeter coverage model}\;
% \emph{ Determine the segment points using perimeter coverage model}\;
}
- \If{$ (s_k.ID $ is the same Previous Leader) And (A.CurrentSize = A.PreviousSize)}{
+ \If{$ (s_j.ID $ is the same Previous Leader) And (A.CurrentSize = A.PreviousSize)}{
\emph{ Use the same previous cover set for current sensing stage}\;
}
\Else{
\emph{Update $a^j_{ik}$; prepare data for IP~Algorithm}\;
- \emph{$\left\{\left(X_{1},\dots,X_{l},\dots,X_{A}\right)\right\}$ = Execute Integer Program Algorithm($A$)}\;
+ \emph{$\left\{\left(X_{1},\dots,X_{k},\dots,X_{A}\right)\right\}$ = Execute Integer Program Algorithm($A$)}\;
\emph{A.PreviousSize = A.CurrentSize}\;
}
- \emph{$s_k.status$ = COMMUNICATION}\;
- \emph{Send $ActiveSleep()$ to each node $l$ in subregion}\;
- \emph{Update $RE_k $}\;
+ \emph{$s_j.status$ = COMMUNICATION}\;
+ \emph{Send $ActiveSleep()$ to each node $k$ in subregion}\;
+ \emph{Update $RE_j $}\;
}
\Else{
- \emph{$s_k.status$ = LISTENING}\;
+ \emph{$s_j.status$ = LISTENING}\;
\emph{Wait $ActiveSleep()$ packet from the Leader}\;
- \emph{Update $RE_k $}\;
+ \emph{Update $RE_j $}\;
}
}
- \Else { Exclude $s_k$ from entering in the current sensing stage}
-\caption{PeCO($s_k$)}
+ \Else { Exclude $s_j$ from entering in the current sensing stage}
+\caption{PeCO($s_j$)}
\label{alg:PeCO}
\end{algorithm}
In this algorithm, A.CurrentSize and A.PreviousSize respectively represent the
current number and the previous number of living nodes in the subnetwork of the
-subregion. Initially, the sensor node checks its remaining energy $RE_k$, which
+subregion. Initially, the sensor node checks its remaining energy $RE_j$, which
must be greater than a threshold $E_{th}$ in order to participate in the current
period. Each sensor node determines its position and its subregion using an
embedded GPS or a location discovery algorithm. After that, all the sensors
difference is more obvious in Figure~\ref{fig3LT}(b) than in
Figure~\ref{fig3LT}(a) because the gain induced by our protocols increases with
time, and the lifetime with a coverage of 50\% is far longer than with
-95\%.
+95\%.
-\begin{figure}[h!]
+\begin{figure} [p]
\centering
\begin{tabular}{@{}cr@{}}
\includegraphics[scale=0.8]{Figures/ch6/R/LT95.eps} & \raisebox{4cm}{(a)} \\
size. DiLCO is better for coverage ratios near 100\%, but in that case PeCO is
not ineffective for the smallest network sizes.
-\begin{figure}[h!]
+\begin{figure} [p]
\centering \includegraphics[scale=0.8]{Figures/ch6/R/LTa.eps}
\caption{Network lifetime for different coverage ratios.}
\label{figLTALL}
-\end{figure}
-
+\end{figure}
-\section{Conclusion}
+ %\FloatBarrier
+\section{Conclusion}
\label{ch6:sec:05}
In this chapter, we have studied the problem of Perimeter-based Coverage Optimization in
