\documentclass[11pt,twoside]{article}\makeatletter

\IfFileExists{xcolor.sty}%
  {\RequirePackage{xcolor}}%
  {\RequirePackage{color}}
\usepackage{colortbl}
\usepackage{wrapfig}
\usepackage{ifxetex}
\ifxetex
  \usepackage{fontspec}
  \usepackage{xunicode}
  \catcode`⃥=\active \def⃥{\textbackslash}
  \catcode`❴=\active \def❴{\{}
  \catcode`❵=\active \def❵{\}}
  \def\textJapanese{\fontspec{Noto Sans CJK JP}}
  \def\textChinese{\fontspec{Noto Sans CJK SC}}
  \def\textKorean{\fontspec{Noto Sans CJK KR}}
  \setmonofont{DejaVu Sans Mono}
  
\else
  \IfFileExists{utf8x.def}%
   {\usepackage[utf8x]{inputenc}
      \PrerenderUnicode{–}
    }%
   {\usepackage[utf8]{inputenc}}
  \usepackage[english]{babel}
  \usepackage[T1]{fontenc}
  \usepackage{float}
  \usepackage[]{ucs}
  \uc@dclc{8421}{default}{\textbackslash }
  \uc@dclc{10100}{default}{\{}
  \uc@dclc{10101}{default}{\}}
  \uc@dclc{8491}{default}{\AA{}}
  \uc@dclc{8239}{default}{\,}
  \uc@dclc{20154}{default}{ }
  \uc@dclc{10148}{default}{>}
  \def\textschwa{\rotatebox{-90}{e}}
  \def\textJapanese{}
  \def\textChinese{}
  \IfFileExists{tipa.sty}{\usepackage{tipa}}{}
\fi
\def\exampleFont{\ttfamily\small}
\DeclareTextSymbol{\textpi}{OML}{25}
\usepackage{relsize}
\RequirePackage{array}
\def\@testpach{\@chclass
 \ifnum \@lastchclass=6 \@ne \@chnum \@ne \else
  \ifnum \@lastchclass=7 5 \else
   \ifnum \@lastchclass=8 \tw@ \else
    \ifnum \@lastchclass=9 \thr@@
   \else \z@
   \ifnum \@lastchclass = 10 \else
   \edef\@nextchar{\expandafter\string\@nextchar}%
   \@chnum
   \if \@nextchar c\z@ \else
    \if \@nextchar l\@ne \else
     \if \@nextchar r\tw@ \else
   \z@ \@chclass
   \if\@nextchar |\@ne \else
    \if \@nextchar !6 \else
     \if \@nextchar @7 \else
      \if \@nextchar (8 \else
       \if \@nextchar )9 \else
  10
  \@chnum
  \if \@nextchar m\thr@@\else
   \if \@nextchar p4 \else
    \if \@nextchar b5 \else
   \z@ \@chclass \z@ \@preamerr \z@ \fi \fi \fi \fi
   \fi \fi  \fi  \fi  \fi  \fi  \fi \fi \fi \fi \fi \fi}
\gdef\arraybackslash{\let\\=\@arraycr}
\def\@textsubscript#1{{\m@th\ensuremath{_{\mbox{\fontsize\sf@size\z@#1}}}}}
\def\Panel#1#2#3#4{\multicolumn{#3}{){\columncolor{#2}}#4}{#1}}
\def\abbr{}
\def\corr{}
\def\expan{}
\def\gap{}
\def\orig{}
\def\reg{}
\def\ref{}
\def\sic{}
\def\persName{}\def\name{}
\def\placeName{}
\def\orgName{}
\def\textcal#1{{\fontspec{Lucida Calligraphy}#1}}
\def\textgothic#1{{\fontspec{Lucida Blackletter}#1}}
\def\textlarge#1{{\large #1}}
\def\textoverbar#1{\ensuremath{\overline{#1}}}
\def\textquoted#1{‘#1’}
\def\textsmall#1{{\small #1}}
\def\textsubscript#1{\@textsubscript{\selectfont#1}}
\def\textxi{\ensuremath{\xi}}
\def\titlem{\itshape}
\newenvironment{biblfree}{}{\ifvmode\par\fi }
\newenvironment{bibl}{}{}
\newenvironment{byline}{\vskip6pt\itshape\fontsize{16pt}{18pt}\selectfont}{\par }
\newenvironment{citbibl}{}{\ifvmode\par\fi }
\newenvironment{docAuthor}{\ifvmode\vskip4pt\fontsize{16pt}{18pt}\selectfont\fi\itshape}{\ifvmode\par\fi }
\newenvironment{docDate}{}{\ifvmode\par\fi }
\newenvironment{docImprint}{\vskip 6pt}{\ifvmode\par\fi }
\newenvironment{docTitle}{\vskip6pt\bfseries\fontsize{22pt}{25pt}\selectfont}{\par }
\newenvironment{msHead}{\vskip 6pt}{\par}
\newenvironment{msItem}{\vskip 6pt}{\par}
\newenvironment{rubric}{}{}
\newenvironment{titlePart}{}{\par }

\newcolumntype{L}[1]{){\raggedright\arraybackslash}p{#1}}
\newcolumntype{C}[1]{){\centering\arraybackslash}p{#1}}
\newcolumntype{R}[1]{){\raggedleft\arraybackslash}p{#1}}
\newcolumntype{P}[1]{){\arraybackslash}p{#1}}
\newcolumntype{B}[1]{){\arraybackslash}b{#1}}
\newcolumntype{M}[1]{){\arraybackslash}m{#1}}
\definecolor{label}{gray}{0.75}
\def\unusedattribute#1{\sout{\textcolor{label}{#1}}}
\DeclareRobustCommand*{\xref}{\hyper@normalise\xref@}
\def\xref@#1#2{\hyper@linkurl{#2}{#1}}
\begingroup
\catcode`\_=\active
\gdef_#1{\ensuremath{\sb{\mathrm{#1}}}}
\endgroup
\mathcode`\_=\string"8000
\catcode`\_=12\relax

\usepackage[a4paper,twoside,lmargin=1in,rmargin=1in,tmargin=1in,bmargin=1in,marginparwidth=0.75in]{geometry}
\usepackage{framed}

\definecolor{shadecolor}{gray}{0.95}
\usepackage{longtable}
\usepackage[normalem]{ulem}
\usepackage{fancyvrb}
\usepackage{fancyhdr}
\usepackage{graphicx}
\usepackage{marginnote}

\renewcommand{\@cite}[1]{#1}


\renewcommand*{\marginfont}{\itshape\footnotesize}

\def\Gin@extensions{.pdf,.png,.jpg,.mps,.tif}

  \pagestyle{fancy}

\usepackage[pdftitle={Improved Energy and Latency Efficient MAC Scheme for Dense Wireless Sensor Networks},
 pdfauthor={}]{hyperref}
\hyperbaseurl{}

	 \paperwidth210mm
	 \paperheight297mm
              
\def\@pnumwidth{1.55em}
\def\@tocrmarg {2.55em}
\def\@dotsep{4.5}
\setcounter{tocdepth}{3}
\clubpenalty=8000
\emergencystretch 3em
\hbadness=4000
\hyphenpenalty=400
\pretolerance=750
\tolerance=2000
\vbadness=4000
\widowpenalty=10000

\renewcommand\section{\@startsection {section}{1}{\z@}%
     {-1.75ex \@plus -0.5ex \@minus -.2ex}%
     {0.5ex \@plus .2ex}%
     {\reset@font\Large\bfseries}}
\renewcommand\subsection{\@startsection{subsection}{2}{\z@}%
     {-1.75ex\@plus -0.5ex \@minus- .2ex}%
     {0.5ex \@plus .2ex}%
     {\reset@font\Large}}
\renewcommand\subsubsection{\@startsection{subsubsection}{3}{\z@}%
     {-1.5ex\@plus -0.35ex \@minus -.2ex}%
     {0.5ex \@plus .2ex}%
     {\reset@font\large}}
\renewcommand\paragraph{\@startsection{paragraph}{4}{\z@}%
     {-1ex \@plus-0.35ex \@minus -0.2ex}%
     {0.5ex \@plus .2ex}%
     {\reset@font\normalsize}}
\renewcommand\subparagraph{\@startsection{subparagraph}{5}{\parindent}%
     {1.5ex \@plus1ex \@minus .2ex}%
     {-1em}%
     {\reset@font\normalsize\bfseries}}


\def\l@section#1#2{\addpenalty{\@secpenalty} \addvspace{1.0em plus 1pt}
 \@tempdima 1.5em \begingroup
 \parindent \z@ \rightskip \@pnumwidth 
 \parfillskip -\@pnumwidth 
 \bfseries \leavevmode #1\hfil \hbox to\@pnumwidth{\hss #2}\par
 \endgroup}
\def\l@subsection{\@dottedtocline{2}{1.5em}{2.3em}}
\def\l@subsubsection{\@dottedtocline{3}{3.8em}{3.2em}}
\def\l@paragraph{\@dottedtocline{4}{7.0em}{4.1em}}
\def\l@subparagraph{\@dottedtocline{5}{10em}{5em}}
\@ifundefined{c@section}{\newcounter{section}}{}
\@ifundefined{c@chapter}{\newcounter{chapter}}{}
\newif\if@mainmatter 
\@mainmattertrue
\def\chaptername{Chapter}
\def\frontmatter{%
  \pagenumbering{roman}
  \def\thechapter{\@roman\c@chapter}
  \def\theHchapter{\roman{chapter}}
  \def\thesection{\@roman\c@section}
  \def\theHsection{\roman{section}}
  \def\@chapapp{}%
}
\def\mainmatter{%
  \cleardoublepage
  \def\thechapter{\@arabic\c@chapter}
  \setcounter{chapter}{0}
  \setcounter{section}{0}
  \pagenumbering{arabic}
  \setcounter{secnumdepth}{6}
  \def\@chapapp{\chaptername}%
  \def\theHchapter{\arabic{chapter}}
  \def\thesection{\@arabic\c@section}
  \def\theHsection{\arabic{section}}
}
\def\backmatter{%
  \cleardoublepage
  \setcounter{chapter}{0}
  \setcounter{section}{0}
  \setcounter{secnumdepth}{2}
  \def\@chapapp{\appendixname}%
  \def\thechapter{\@Alph\c@chapter}
  \def\theHchapter{\Alph{chapter}}
  \appendix
}
\newenvironment{bibitemlist}[1]{%
   \list{\@biblabel{\@arabic\c@enumiv}}%
       {\settowidth\labelwidth{\@biblabel{#1}}%
        \leftmargin\labelwidth
        \advance\leftmargin\labelsep
        \@openbib@code
        \usecounter{enumiv}%
        \let\p@enumiv\@empty
        \renewcommand\theenumiv{\@arabic\c@enumiv}%
	}%
  \sloppy
  \clubpenalty4000
  \@clubpenalty \clubpenalty
  \widowpenalty4000%
  \sfcode`\.\@m}%
  {\def\@noitemerr
    {\@latex@warning{Empty `bibitemlist' environment}}%
    \endlist}

\def\tableofcontents{\section*{\contentsname}\@starttoc{toc}}
\parskip0pt
\parindent1em
\def\Panel#1#2#3#4{\multicolumn{#3}{){\columncolor{#2}}#4}{#1}}
\newenvironment{reflist}{%
  \begin{raggedright}\begin{list}{}
  {%
   \setlength{\topsep}{0pt}%
   \setlength{\rightmargin}{0.25in}%
   \setlength{\itemsep}{0pt}%
   \setlength{\itemindent}{0pt}%
   \setlength{\parskip}{0pt}%
   \setlength{\parsep}{2pt}%
   \def\makelabel##1{\itshape ##1}}%
  }
  {\end{list}\end{raggedright}}
\newenvironment{sansreflist}{%
  \begin{raggedright}\begin{list}{}
  {%
   \setlength{\topsep}{0pt}%
   \setlength{\rightmargin}{0.25in}%
   \setlength{\itemindent}{0pt}%
   \setlength{\parskip}{0pt}%
   \setlength{\itemsep}{0pt}%
   \setlength{\parsep}{2pt}%
   \def\makelabel##1{\upshape ##1}}%
  }
  {\end{list}\end{raggedright}}
\newenvironment{specHead}[2]%
 {\vspace{20pt}\hrule\vspace{10pt}%
  \phantomsection\label{#1}\markright{#2}%

  \pdfbookmark[2]{#2}{#1}%
  \hspace{-0.75in}{\bfseries\fontsize{16pt}{18pt}\selectfont#2}%
  }{}
      \def\TheFullDate{2011-09 2011-08-19 (revised: 2011 September 19 August 2011)}
\def\TheID{\makeatother }
\def\TheDate{2011-09 2011-08-19}
\title{Improved Energy and Latency Efficient MAC Scheme for Dense Wireless Sensor Networks}
\author{}\makeatletter 
\makeatletter
\newcommand*{\cleartoleftpage}{%
  \clearpage
    \if@twoside
    \ifodd\c@page
      \hbox{}\newpage
      \if@twocolumn
        \hbox{}\newpage
      \fi
    \fi
  \fi
}
\makeatother
\makeatletter
\thispagestyle{empty}
\markright{\@title}\markboth{\@title}{\@author}
\renewcommand\small{\@setfontsize\small{9pt}{11pt}\abovedisplayskip 8.5\p@ plus3\p@ minus4\p@
\belowdisplayskip \abovedisplayskip
\abovedisplayshortskip \z@ plus2\p@
\belowdisplayshortskip 4\p@ plus2\p@ minus2\p@
\def\@listi{\leftmargin\leftmargini
               \topsep 2\p@ plus1\p@ minus1\p@
               \parsep 2\p@ plus\p@ minus\p@
               \itemsep 1pt}
}
\makeatother
\fvset{frame=single,numberblanklines=false,xleftmargin=5mm,xrightmargin=5mm}
\fancyhf{} 
\setlength{\headheight}{14pt}
\fancyhead[LE]{\bfseries\leftmark} 
\fancyhead[RO]{\bfseries\rightmark} 
\fancyfoot[RO]{}
\fancyfoot[CO]{\thepage}
\fancyfoot[LO]{\TheID}
\fancyfoot[LE]{}
\fancyfoot[CE]{\thepage}
\fancyfoot[RE]{\TheID}
\hypersetup{citebordercolor=0.75 0.75 0.75,linkbordercolor=0.75 0.75 0.75,urlbordercolor=0.75 0.75 0.75,bookmarksnumbered=true}
\fancypagestyle{plain}{\fancyhead{}\renewcommand{\headrulewidth}{0pt}}

\date{}
\usepackage{authblk}

\providecommand{\keywords}[1]
{
\footnotesize
  \textbf{\textit{Index terms---}} #1
}

\usepackage{graphicx,xcolor}
\definecolor{GJBlue}{HTML}{273B81}
\definecolor{GJLightBlue}{HTML}{0A9DD9}
\definecolor{GJMediumGrey}{HTML}{6D6E70}
\definecolor{GJLightGrey}{HTML}{929497} 

\renewenvironment{abstract}{%
   \setlength{\parindent}{0pt}\raggedright
   \textcolor{GJMediumGrey}{\rule{\textwidth}{2pt}}
   \vskip16pt
   \textcolor{GJBlue}{\large\bfseries\abstractname\space}
}{%   
   \vskip8pt
   \textcolor{GJMediumGrey}{\rule{\textwidth}{2pt}}
   \vskip16pt
}

\usepackage[absolute,overlay]{textpos}

\makeatother 
      \usepackage{lineno}
      \linenumbers
      
\begin{document}

             \author[1]{Dr. K. P.  Sampoornam}

             \affil[1]{  K.S.R.College of Engineering}

\renewcommand\Authands{ and }

\date{\small \em Received: 18 July 2011 Accepted: 8 August 2011 Published: 19 August 2011}

\maketitle


\begin{abstract}
        


The sensor nodes in the wireless sensor networks have limited battery power, which motivates to work on energy conserved MAC schemes for better lifetime and latency efficient. Previous work carried out in energy conserved MAC schemes are limit the idle listening time, reduces overhearing (sensor node hear a packet destined for other nodes) and minimizing the used control packet size. The current existing work presented ELE-MAC (i.e. Energy Latency Efficient MAC) which adopts less control packets to preserve energy in sparsely distributed sensor nodes of the wireless sensor networks. It performs statistically the same or better latency characteristic compared to adaptive SMAC. ELE-MAC follows the adaptive listening technique, which reduce the sleep delay introduced by the periodic sleep of each node in case of a multi-hops network. The proposal in this work, extends the ELE-MAC to work efficiently with wireless sensor network comprises of high node density by combining the RTS and SYNC control packets. The extended version uses two separate frequencies for data and control packets to avoid the use of handshake mechanisms (e.g. RTS/CTS) in order to reduce energy consumption and packet delay. It enables a receiver to send a busy tone signal on th  control channel and notify the neighbors about the ongoing reception of data in progress. This process avoids packet collisions and in turn improves the node lifetime and throughput. The nodes in a sensor network have their own different traffic loads according to the tasks assigned and their locations. The extension of ELE MAC adopts the different traffic loads of each node as performance metric for reducing the latency. Each sensor node calculates its utilization after the last synchronization time, and adjusts its duty cycle according to the calculated utilization, and then send new schedule to its neighbors via broadcasting.

\end{abstract}


\keywords{Wireless Sensor Network, Lifetime, Traffic load, Energy and Latency, MAC.}

\begin{textblock*}{18cm}(1cm,1cm) % {block width} (coords) 
\textcolor{GJBlue}{\LARGE Global Journals \LaTeX\ JournalKaleidoscope\texttrademark}
\end{textblock*}

\begin{textblock*}{18cm}(1.4cm,1.5cm) % {block width} (coords) 
\textcolor{GJBlue}{\footnotesize \\ Artificial Intelligence formulated this projection for compatibility purposes from the original article published at Global Journals. However, this technology is currently in beta. \emph{Therefore, kindly ignore odd layouts, missed formulae, text, tables, or figures.}}
\end{textblock*}


\let\tabcellsep& 	 	 		 \par
Improved Energy and Latency Efficient MAC Scheme for Dense Wireless Sensor Networks K. P. Sampoornam ? , Dr. K. Rameshwaran ? Abstract -The sensor nodes in the wireless sensor networks have limited battery power, which motivates to work on energy conserved MAC schemes for better lifetime and latency efficient. Previous work carried out in energy conserved MAC schemes are limit the idle listening time, reduces overhearing (sensor node hear a packet destined for other nodes) and minimizing the used control packet size. The current existing work presented ELE-MAC (i.e. Energy Latency Efficient MAC) which adopts less control packets to preserve energy in sparsely distributed sensor nodes of the wireless sensor networks. It performs statistically the same or better latency characteristic compared to adaptive SMAC. ELE-MAC follows the adaptive listening technique, which reduce the sleep delay introduced by the periodic sleep of each node in case of a multi-hops network.\par
The proposal in this work, extends the ELE-MAC to work efficiently with wireless sensor network comprises of high node density by combining the RTS and SYNC control packets. The extended version uses two separate frequencies for data and control packets to avoid the use of handshake mechanisms (e.g. RTS/CTS) in order to reduce energy consumption and packet delay. It enables a receiver to send a busy tone signal on the control channel and notify the neighbors about the ongoing reception of data in progress. This process avoids packet collisions and in turn improves the node lifetime and throughput.\par
The nodes in a sensor network have their own different traffic loads according to the tasks assigned and their locations. The extension of ELE MAC adopts the different traffic loads of each node as performance metric for reducing the latency. Each sensor node calculates its utilization after the last synchronization time, and adjusts its duty cycle according to the calculated utilization, and then send new schedule to its neighbors via broadcasting. Keywords : Wireless Sensor Network, Lifetime, Traffic load, Energy and Latency, MAC 
\section[{I. INTRODUCTION}]{I. INTRODUCTION}\par
ireless sensor network (WSN) is a collection of sensor nodes that interact with each other intentionally to gather information from the surveillance area. Sensor nodes support unattended operation for long duration, usually in remote areas. WSN applications such as environmental monitoring \hyperref[b0]{[1]}, object tracking \hyperref[b1]{[2]} and intelligent buildings \hyperref[b2]{[3]} require a reliable data transmission and can endure long periods Author ? : Department of ECE, K.S.R. College of Engg., Tiruchengode-637215 Telephone : 9629377780 E-mail : sambu\textunderscore swasti@yahoo.com Author ? : Principal, JJ College of Engg, Tiruchirappalli -620 009. Telephone : 9952266566 E-mail : krameshwaran@gmail.com of operation. The limitation of sensor nodes are low processing capabilities (delay attenuation), low power battery and low memory capacities which initiates to improve those constraints in increasing the network life time of wireless sensor networks.\par
Medium access control (MAC) layer manages the medium accessibility to minimize collision among transmitting packets. Packet collision requires node to retransmit the packet, hence consuming additional energy. MAC layer controls the physical (radio transceiver) layer which has greater effect on overall energy consumption and lifetime of a node. The nodes sometimes falsely assumed that the channel is in idle condition and start the transmission which results in data collision lead to more energy requirement. In some cases nodes are exposed due to out of receiver range which leads to overhearing and increases the delay of transmission. In few other cases nodes receive one of two simultaneous transmissions, which creates complex traffic load control. The idle listening of a sensor node due to continuous listening of the channel to receive a potential packet from its neighboring nodes consumes more energy.\par
Energy inefficiency caused by the idle-listening problem and high collision probability can be avoided in Time Division Multiple Access (TDMA) based MAC protocols. The existing work presented an ELE-MAC Energy Latency Efficient MAC with distributed TDMA mechanism which possesses an active/sleep mechanism for efficient energy usage with predefined duty cycle. However the ELE-MAC work on different traffic load condition affects the overall network lifetime of the sensor network. In this paper, we presented an improved version of ELE-MAC which works on balancing the different traffic load conditions of the sensor node transmission on the target object being detected. 
\section[{II. LITERATURE REVIEW}]{II. LITERATURE REVIEW}\par
MAC protocol is classified into random access and conflict-free multiple access. Traditional MAC protocols such as ALOHA \hyperref[b4]{[5]}, CSMA \hyperref[b5]{[6]}, and MACA \hyperref[b6]{[7]}, are designed based on contention based random access approach. The classic ALOHA protocol uses simple transmission mechanism where node transmits a packet when it is generated. However, its simplicity comes at an expense of very high probability of packet Access (CSMA) protocol is developed \hyperref[b5]{[6]} with the objective of minimizing collision by implementing a small time for channel listening in order to detect channel activity. However, the protocol cannot solve the hidden terminal problem which normally occurs in ad-hoc networks where the radio range is not large enough to allow communication between arbitrary nodes and two or more nodes may share a common neighbor while being out of each other's reach. The MACA protocol introduces a three-way handshake mechanism to make hidden nodes aware of upcoming transmission, so collision at neighboring nodes can be avoided. However, the handshaking mechanism causes overhead on control packet.\par
All these protocols require all nodes to continuously listen to the channel due to unpredictable packet transmission by its neighboring nodes, hence introducing a problem called idle-listening problem. This situation causes a node to expend a lot of wasteful energy causing the implementation of these protocols in WSN inefficient. Sensor-MAC (SMAC) protocol \hyperref[b7]{[8]} attempted to solve the problems by introducing activesleep cycles in the presence of random access channel. Node will execute a variant of MACA contention-based MAC protocol during active period to minimize the hidden terminal problem, while turning its radio off during sleep period to reduce idle listening problem. However SMAC implements neighbors' information variables called Network Allocation Vector (NAV) \hyperref[b8]{[9]} for its collision avoidance technique. Node checks the NAV value before sending the RTS message. Nevertheless, implementing contention based mechanism is still vulnerable to collision due to random mechanism in its data packet transmission.\par
Energy inefficiency caused by the idle-listening problem and high collision probability can be avoided in Time Division Multiple Access (TDMA) based protocols. In TDMA-based protocol such as HiperLan-II \hyperref[b9]{[10]}, time is divided into several frames, and a frame is divided into a number of time slots. Since all transmissions within the frame are pre-scheduled, it is possible for a node to sleep when it is not expected to transmit or receive any packets. Thus, the TDMA-based MAC protocol can clearly avoid the over-emitting problem. Since only the owner of the time slot is allowed to transmit a packet, collision problem can be avoided significantly.\par
Tahar et al., \hyperref[b0]{[1]} presented an energy efficient MAC protocol which realizes both energy efficiency and improve the channel utilization compared to the already existed techniques. For this they provided ELE-MAC with the inputs from adaptive SMAC scheme. In this a control packet strategy which presented a packet exchange sequence aiming to minimize the energy wasted by control packets and to decrease latency.\par
However different traffic load condition of the sensor nodes on transmission of target detected objects at any given time also further increases the latency and energy. The proposal in this work present an another variant of ELE-MAC which handles the different load conditions based on load distribution and scheduling mechanism of each and every sensor nodes of the network to improve the overall lifetime. 
\section[{III. LOAD BALANCED ELE-MAC}]{III. LOAD BALANCED ELE-MAC}\par
In the wireless sensor network, the control packet has greater impact on the network power consumption which is comparable to the size of data packets. Energy consumption is reduced by optimizing the exchanged control packets. This motivates to present energy efficient MAC protocol that minimizes the exchanged control packets (ELE-MAC) compared to that of adaptive SMAC protocol. ELE-MAC control packets shown in The ELE-MAC control packet provides two additional fields (i.e. ACK destination Node Address and ACK flag) which allow the new RTS packet to play the role at the same time of an ACK and a RTS. This new packet will be exchanged only when data are sent adaptively (i.e. not at the scheduled listen time). Thus, no ACK packet will be emitted in that case. The transmission is performed normally (i.e. at the scheduled listen time). Each data packet received is followed by an ACK to the sender.\par
The operation of ELE-MAC shown in Fig 3 explains the operation that node A has data to be transmitted to node B to end in node C which is the sink of the illustrated topology. The ELE-MAC scheme starts the adaptive wake up period immediately after receiving the data packet instead of waiting for the ACK packet like for the SMAC adaptive listening mechanism. This modification is made for allowing a receiver to inform its neighbors about the data reception through the ACK flag field. Also, this packet allows the receiver to mention its need to transmit the received data packet to the nexthop if it exists (i.e. send RTS).\par
The most common workload in sensor networks consists on small periodic data packets. Thus, ELE-MAC doesn't propose a fragmentation mechanism. Like IEEE 802.11 and SMAC, broadcast packets are sent only when virtual and physical carrier sense indicate that the medium is free. In addition, these packets will not be preceded by RTS/CTS and will not be acknowledged by their recipients.\par
The load balance scheme proposed for ELE-MAC to multi-hop multi-channel sensor networks. Based dynamically alternates the communication channels. As a result, the extra load from over-loaded channels is directed to under-loaded channels with a computed switch probability.\par
In addition a high throughput is achieved with stabilized load conditions on the sensor nodes during the transmission of more number of target objects being detected. The performance of the load balance algorithm is evaluated through simulation studies on both ELE-MAC of energy variant and load variant. The simulation is carried for improve load balanced ELE-MAC with existing ELE-MAC in NS-2. By comparing with SMAC (in its two alternatives), it is shown that load balance variant of ELE-MAC shows better lifetime of the sensor network in terms of load stability, latency and energy consumption. The adaptive SMAC implementation deployed in this NS's version doesn't provide us with the correctly nodes' energy consumption. Further, the problem resides in the implemented Energy Model. This is because it doesn't take into consideration the energy wasted by idle listening (i.e. doesn't drain energy in the sleep/wakeup methods). Henceforth, to enable the right tracking of the energy consumed by each node at any time, we tune the energy model and the SMAC sources.\par
The behavior of the proposed load variant ELE-MAC when varying the traffic load and because of the limited transmission range of wireless network interfaces (i.e. multiple network hops may be required for one node to exchange data) a multi-hops environment is required. Similar to the test bed realized for evaluating SMAC on a multi-hop networks, a linear topology composed from 40 to 60 nodes with only one source and a sink which is chosen the later node in the multihops chain. This simple topology allows us to concentrate on the inherent properties of load variant and energy variant ELE-MAC. The routing protocol makes greedy forwarding decisions using information about a router's immediate neighbors in the network topology. In fact, to let each node hear only its next neighbor, we put nodes distant by 100 meters taking into account that the transmission range in NS-2 is set to 150 meters. No mobility is assumed in our simulation scenarios. As the goal of our simulation is to compare the performance of SMAC with ELE-MAC, we choose our traffic source to be constant bit rate (CBR) source. The NS-2 ELE-MAC and load variant simulation parameters are analyzed to extract the useful traces and to compute the energy consumption as well as the latency with TCL scripts. The simulation is carried out for several pause time to obtain significant statistical results.\par
The Control packets analysis show the resultant of energy variant and load variant ELE-MAC with different traffic rate sources on the wireless sensor network. Energy variant ELE-MAC exchanges few control packets compared with load variant initially however on continuous simulation load variant shows better result than energy variant. Fig. \hyperref[fig_4]{6} presents the energy consumption performance of Energy variant and Load variant ELE-MAC. Conserve the energy which would be lost by the control packets overhead by maintaining the stability of load on all the sensor nodes.\par
The Latency analysis handles the end-to-end delay quantification from the simulation viewpoint. ELE-MAC energy and load variant measure the total time required to transmit the generated data packets. Load ELE-MAC achieves better latency performance compared to that of energy ELE-MAC. Fig. 7 plots the latency performance of Energy variant and Load variant ELE-MAC. The load distribution and scheduling policy of load variant ELE-MAC reduces the listening time of the sensor node in the MAC layer which in turn reduces overhearing and latency. As can be seen in Fig.  {\ref 8} the scheduling policy of load variant ELE-MAC helps the node transmission stability to its optimal level.  \begin{figure}[htbp]
\noindent\textbf{}\includegraphics[]{image-2.png}
\caption{\label{fig_0}}\end{figure}
 \begin{figure}[htbp]
\noindent\textbf{}\includegraphics[]{image-3.png}
\caption{\label{fig_1}}\end{figure}
 \begin{figure}[htbp]
\noindent\textbf{3}\includegraphics[]{image-4.png}
\caption{\label{fig_2}Fig 3 :}\end{figure}
 \begin{figure}[htbp]
\noindent\textbf{12}\includegraphics[]{image-5.png}
\caption{\label{fig_3}Fig 1 :Fig 2 :}\end{figure}
 \begin{figure}[htbp]
\noindent\textbf{6}\includegraphics[]{image-6.png}
\caption{\label{fig_4}Fig 6 :}\end{figure}
  			\footnote{© 2011 Global Journals Inc. (US)} 			\footnote{© 2011 Global Journals Inc. (US) Global Journal of Computer Science and Technology Volume XI Issue XV Version I} 		 		\backmatter  			 
\subsection[{Global Journal of Computer Science and Technology Volume XI Issue XV Version I}]{Global Journal of Computer Science and Technology Volume XI Issue XV Version I}\par
Improved Energy and Latency Efficient MAC Scheme for Dense Wireless Sensor Networks (decreased to 23\%) compared to that of existing ELE-MAC. 
\subsection[{This page is intentionally left blank}]{This page is intentionally left blank}\par
Improved Energy and Latency Efficient MAC Scheme for Dense Wireless Sensor Networks 60			 			  				\begin{bibitemlist}{1}
\bibitem[ IEEE Computer Society. Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specificatio. IEEE Std ()]{b7}\label{b7} 	 		\textit{},  	 	 		\textit{IEEE Computer Society. Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specificatio. IEEE Std}  		1997. 802  (11) .  	 
\bibitem[Ezzedine et al. ()]{b0}\label{b0} 	 		‘An Energy-Latency-Efficient MAC Protocol for Wireless Sensor Networks’.  		 			Tahar Ezzedine 		,  		 			Mohamed Miladi 		,  		 			Ridha Bouallegue 		.  	 	 		\textit{International Journal of Electrical and Computer Engineering}  		2009. 4  (13) .  	 
\bibitem[Lin et al. ()]{b8}\label{b8} 	 		‘ATPC: Adaptive Transmission Power Control for Wireless Sensor Networks’.  		 			S Lin 		,  		 			J Zhang 		,  		 			G Zhou 		,  		 			L Gu 		,  		 			T He 		,  		 			J A Stankovic 		.  	 	 		\textit{Proceedings of the 4th International Conf. on Embedded Networked Sensor Systems},  				 (the 4th International Conf. on Embedded Networked Sensor Systems)  		2006. p. .  	 
\bibitem[Hoesel and Havinga (2005)]{b3}\label{b3} 	 		‘Collision-free Time Slot Reuse in MultihopWireless Sensor Networks’.  		 			L V Hoesel 		,  		 			P Havinga 		.  	 	 		\textit{Proc. Int. Conf. on Intelligent Sensor, Sensor Networks and Information Processing},  				 (Int. Conf. on Intelligent Sensor, Sensor Networks and Information essing)  		Dec. 2005. p. .  	 
\bibitem[Van Hoesel and Havinga (2006)]{b4}\label{b4} 	 		\textit{Design Aspects of An Energy-Efficient .Lightweight Medium Access Control Protocol for Wireless Sensor Networks},  		 			L F W Van Hoesel 		,  		 			P J M Havinga 		.  		July 17. 2006.  	 
\bibitem[Rozeha Abd Rashid et al. ()]{b9}\label{b9} 	 		‘Enhanced Lightweight Medium Access Control Protocol’.  		 			Wan Rozeha Abd Rashid 		,  		 			W Mohd Ariff Ehsan 		,  		 			Norsheila Embong 		,  		 			Fisal 		.  	 	 		\textit{Proceedings of the International Conference on Circuits},  				 (the International Conference on Circuits)  		Dec 2-4, 2009.  	 	 (Radio Frequency \& Microwave Int. Conf. (RFM) KL) 
\bibitem[Ye et al. (2004)]{b2}\label{b2} 	 		‘Medium Access Control with Coordinated Adaptive Sleeping for Wireless Sensor Networks’.  		 			W Ye 		,  		 			J Heidemann 		,  		 			D Estrin 		.  	 	 		\textit{IEEE/ACM Trans. Net}  		June 2004. 12  (3)  p. .  	 
\bibitem[Hill et al. ()]{b5}\label{b5} 	 		\textit{System Architecture Directions for Networked Sensors. In Architectural Support for Programming Languages and Operating Systems},  		 			J Hill 		,  		 			R Szewczyk 		,  		 			A Woo 		,  		 			S Hollar 		,  		 			D E Culler 		,  		 			K Pister 		.  		2000. p. .  	 
\bibitem[Gay et al. (2003)]{b6}\label{b6} 	 		‘The NesC Language: A Holistic Approach to Networked Embedded System’.  		 			D Gay 		,  		 			P Levis 		,  		 			R Behren 		,  		 			M Welsh 		,  		 			E Brewer 		,  		 			D Culler 		.  	 	 		\textit{Proc. ACM SIGPUN 2003, Conf. on Programming Language Design and Implementation},  				 (ACM SIGPUN 2003, Conf. on Programming Language Design and Implementation)  		June 2003. p. .  	 
\bibitem[Mainwaring et al. ()]{b1}\label{b1} 	 		\textit{Wireless Sensor Networks for Habitat Monitoring. International Workshop on Wireless Sensor Networks and Applications},  		 			J Mainwaring 		,  		 			R Polastre 		,  		 			D Szewczyk 		,  		 			J Culler 		,  		 			Anderson 		.  		2002. p. .  	 
\end{bibitemlist}
 			 		 	 
\end{document}
