X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/ThesisAli.git/blobdiff_plain/8650c8fef559350da23a6febc1c3c4bded1609f1..647071a417ef52e995581f796c0c32cf6915cd51:/CHAPITRE_04.tex diff --git a/CHAPITRE_04.tex b/CHAPITRE_04.tex index 0cdeebe..62a78b7 100644 --- a/CHAPITRE_04.tex +++ b/CHAPITRE_04.tex @@ -29,11 +29,11 @@ The area of interest can be divided using the divide-and-conquer strategy into smaller areas, called subregions, and then our MuDiLCO protocol will be implemented in each subregion in a distributed way. -As can be seen in Figure~\ref{fig2}, our protocol works in periods fashion, +As can be seen in Figure~\ref{fig2}, our protocol works in periods fashion, where each is divided into 4 phases: Information~Exchange, Leader~Election, Decision, and Sensing. Each sensing phase may be itself divided into $T$ rounds and for each round a set of sensors (a cover set) is responsible for the sensing -task. In this way a multiround optimization process is performed during each +task. In this way a multiround optimization process is performed during each period after Information~Exchange and Leader~Election phases, in order to produce $T$ cover sets that will take the mission of sensing for $T$ rounds. \begin{figure}[ht!] @@ -46,18 +46,9 @@ produce $T$ cover sets that will take the mission of sensing for $T$ rounds. This protocol minimizes the impact of unexpected node failure (not due to batteries running out of energy), because it works in periods. - On the one hand, if a node failure is detected before making the -decision, the node will not participate to this phase, and, on the other hand, -if the node failure occurs after the decision, the sensing task of the network -will be temporarily affected: only during the period of sensing until a new -period starts. + On the one hand, if a node failure is detected before making the decision, the node will not participate to this phase, and, on the other hand, if the node failure occurs after the decision, the sensing task of the network will be temporarily affected: only during the period of sensing until a new period starts. -The energy consumption and some other constraints can easily be taken into -account, since the sensors can update and then exchange their information -(including their residual energy) at the beginning of each period. However, the -pre-sensing phases (Information Exchange, Leader Election, and Decision) are -energy consuming for some nodes, even when they do not join the network to -monitor the area. +The energy consumption and some other constraints can easily be taken into account, since the sensors can update and then exchange their information (including their residual energy) at the beginning of each period. However, the pre-sensing phases (Information Exchange, Leader Election, and Decision) are energy consuming for some nodes, even when they do not join the network to monitor the area. These phases can be described in more details as follow: @@ -71,7 +62,7 @@ The leader election in each subregion is similar to that one which is described \subsection{Decision phase} \label{ch4:sec:02:02:03} -Each WSNL will solve an integer program to select which cover sets will be +Each WSNL will solve an integer program to select which cover sets will be activated in the following sensing phase to cover the subregion to which it belongs. The integer program will produce $T$ cover sets, one for each round. The WSNL will send an Active-Sleep packet to each sensor in the subregion based @@ -316,7 +307,9 @@ reduce the advantage of the optimization. In fact, there is a balance between the benefit from the optimization and the execution time needed to solve it. Therefore, we have set the number of subregions to 16 rather than 32. -We have used an energy consumption model, which is presented in chapter 1, section \ref{ch1:sec9:subsec2}. The initial energy of each node is randomly set in the interval $[500;700]$. A sensor node will not participate in the next round if its remaining energy is less than $E_{R}=36~\mbox{Joules}$, the minimum energy needed for the node to stay alive during one round. This value has been computed by multiplying the energy consumed in active state (9.72 mW) by the time in second for one round (3600 seconds). According to the interval of initial energy, a sensor may be alive during at most 20 rounds. +We have used an energy consumption model, which is presented in chapter 3, section \ref{ch3:sec:04:02}. + +%The initial energy of each node is randomly set in the interval $[500;700]$. A sensor node will not participate in the next round if its remaining energy is less than $E_{R}=36~\mbox{Joules}$, the minimum energy needed for the node to stay alive during one round. This value has been computed by multiplying the energy consumed in active state (9.72 mW) by the time in second for one round (3600 seconds). According to the interval of initial energy, a sensor may be alive during at most 20 rounds. \subsection{Metrics} \label{ch4:sec:03:02}