ns-wireless-tutorial

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  • 2022-04-23 10:50
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一个如何在ns2中仿真无线微波节点,TCP应用的例子,来自香港大学
15883839tr_ns2_wireless.rar
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<html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta charset="utf-8"> <meta name="generator" content="pdf2htmlEX"> <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"> <link rel="stylesheet" href="https://static.pudn.com/base/css/base.min.css"> <link rel="stylesheet" href="https://static.pudn.com/base/css/fancy.min.css"> <link rel="stylesheet" href="https://static.pudn.com/prod/directory_preview_static/62636ab04c65f41259b00622/raw.css"> <script src="https://static.pudn.com/base/js/compatibility.min.js"></script> <script src="https://static.pudn.com/base/js/pdf2htmlEX.min.js"></script> <script> try{ pdf2htmlEX.defaultViewer = new pdf2htmlEX.Viewer({}); }catch(e){} </script> <title></title> </head> <body> <div id="sidebar" style="display: none"> <div id="outline"> </div> </div> <div id="pf1" class="pf w0 h0" data-page-no="1"><div class="pc pc1 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62636ab04c65f41259b00622/bg1.jpg"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls0 ws0">A<span class="_ _0"></span> T<span class="_ _1"></span>utorial <span class="_ _2"></span>of W<span class="_ _3"></span>ir<span class="_ _3"></span>eless <span class="_ _2"></span>Simulation <span class="_ _2"></span>in <span class="_ _2"></span>NS-2 </div><div class="t m0 x1 h3 y2 ff2 fs1 fc0 sc0 ls1 ws1">Y<span class="_ _0"></span>ue W<span class="_ _4"></span>ang </div><div class="t m0 x1 h3 y3 ff2 fs1 fc0 sc0 ls2 ws2">Department of CSE, CUHK </div><div class="t m0 x1 h3 y4 ff2 fs1 fc1 sc0 ls3 ws3">ywang@cse.cuhk.edu.<span class="_ _3"></span>hk</div><div class="t m0 x2 h3 y5 ff2 fs1 fc0 sc0 ls4 ws3"> </div><div class="t m0 x1 h3 y6 ff2 fs1 fc0 sc0 ls4 ws3"> </div><div class="t m0 x1 h3 y7 ff2 fs1 fc0 sc0 ls5 ws4">(V<span class="_ _0"></span>ersion 2, revised at July<span class="_ _3"></span> 20, 2007) </div><div class="t m0 x1 h4 y8 ff1 fs2 fc0 sc0 ls6 ws5">1. Intr<span class="_ _3"></span>oduction to ns-2<span class="ff2 ls4 ws3"> </span></div><div class="t m0 x1 h5 y9 ff1 fs3 fc0 sc0 ls7 ws6">1.1 ns-2 </div><div class="t m0 x1 h3 ya ff2 fs1 fc0 sc0 ls8 ws7">Ns-2 [1] is a packet-level s<span class="_ _3"></span>imulator which is essentially a <span class="ff3 ls9 ws3">centraliz<span class="_ _3"></span>ed<span class="ff2 ls5 ws8"> discrete event scheduler t<span class="_ _3"></span>o </span></span></div><div class="t m0 x1 h3 yb ff2 fs1 fc0 sc0 lsa ws9">schedule the eve<span class="_ _3"></span>nts such as packet and timer e<span class="lsb wsa">xpirat<span class="_ _3"></span>ion. The centralized event scheduler cannot </span></div><div class="t m0 x1 h3 yc ff2 fs1 fc0 sc0 ls5 wsb">accurately emula<span class="_ _3"></span>te &#8220;events occurred at the sam<span class="_ _3"></span>e time&#8221;, instead, it ca<span class="_ _3"></span>n only handle events occ<span class="_ _3"></span>urred </div><div class="t m0 x1 h3 yd ff2 fs1 fc0 sc0 ls3 wsc">one by one <span class="_ _3"></span>in time. How<span class="_ _3"></span>ever<span class="_ _3"></span>, this is not<span class="_ _3"></span> a serious problem<span class="_ _3"></span> in most network sim<span class="_ _3"></span>ulations, because </div><div class="t m0 x1 h3 ye ff2 fs1 fc0 sc0 lsa wsd">the events her<span class="_ _3"></span>e are often transitory<span class="_ _4"></span>. Besides, ns-2 im<span class="_ _3"></span>plements a variety<span class="_ _3"></span> of network com<span class="_ _3"></span>ponents </div><div class="t m0 x1 h3 yf ff2 fs1 fc0 sc0 lsc wse">and protocols. Not<span class="_ _2"></span>ably<span class="_ _4"></span>, the wirele<span class="_ _2"></span>ss extension,<span class="lsd wsf"> derived from CMU Monarc<span class="_ _2"></span><span class="lsb ws10">h Project [2], <span class="_ _3"></span>has 2 </span></span></div><div class="t m0 x1 h3 y10 ff2 fs1 fc0 sc0 ls3 ws11">assumptions sim<span class="_ _3"></span>plifying the physical w<span class="_ _3"></span>orld: </div><div class="t m0 x3 h3 y11 ff2 fs1 fc0 sc0 ls8 ws12">(1) Nodes do not m<span class="_ _3"></span>ove significan<span class="lse ws13">tly over the length of time th<span class="ws14">ey transmit or receive<span class="_ _3"></span> a packet. </span></span></div><div class="t m0 x1 h3 y12 ff2 fs1 fc0 sc0 lsf ws15">This assumption <span class="_ _3"></span>holds only for mobile nodes of <span class="_ _3"></span>high-rate and low-spe<span class="_ _3"></span>ed. Consider a node with <span class="_ _3"></span>the </div><div class="t m0 x1 h3 y13 ff2 fs1 fc0 sc0 ls3 ws16">sending rate of 10K<span class="_ _3"></span>bps and moving spee<span class="_ _3"></span>d of 10m/s, during its receivin<span class="_ _3"></span>g a packet of 1500B, the </div><div class="t m0 x1 h3 y14 ff2 fs1 fc0 sc0 lsf ws15">node moves 12m<span class="_ _3"></span>. Thus, the <span class="_ _3"></span>surrounding can change sig<span class="_ _3"></span>nificantly and cause rece<span class="_ _3"></span>ption failure. </div><div class="t m0 x3 h3 y15 ff2 fs1 fc0 sc0 lsf ws15">(2) Node velocity is <span class="_ _3"></span>insignificant com<span class="_ _3"></span>pared to the speed of ligh<span class="_ _3"></span>t. In particular<span class="_ _3"></span>, none<span class="_ _3"></span> of the </div><div class="t m0 x1 h3 y16 ff2 fs1 fc0 sc0 lsf ws15">provided propaga<span class="_ _3"></span>tion models include D<span class="_ _3"></span>oppler effects,<span class="_ _3"></span> although they could. </div><div class="t m0 x3 h3 y17 ff2 fs1 fc0 sc0 ls4 ws3"> </div><div class="t m0 x1 h5 y18 ff1 fs3 fc0 sc0 ls10 ws17">1.2 GloMoSim and OPNET<span class="ff2 fs1 ls4 ws3"> </span></div><div class="t m0 x1 h3 y19 ff2 fs1 fc0 sc0 ls11 ws18">GloMoSim [3] is a<span class="_ _3"></span>nother open-source netw<span class="_ _3"></span>ork simulator which is bas<span class="_ _3"></span>ed on parallel programm<span class="_ _3"></span>ing. </div><div class="t m0 x1 h3 y1a ff2 fs1 fc0 sc0 ls12 ws19">Hopefully<span class="_ _4"></span>, it can emulate the real<span class="_ _3"></span> world more <span class="ls13 ws1a">accurately<span class="_ _4"></span>. However<span class="_ _3"></span>, it may be <span class="_ _3"></span>hard to debug </span></div><div class="t m0 x1 h3 y1b ff2 fs1 fc0 sc0 ls14 ws1b">parallel program<span class="_ _3"></span>s. Although GloMoSim<span class="_ _3"></span> currently <span class="ls15 ws1c">solely supports wireless networ<span class="_ _3"></span>ks, it provides </span></div><div class="t m0 x1 h3 y1c ff2 fs1 fc0 sc0 ls5 ws1d">more physical-lay<span class="_ _3"></span>er models than ns-2. Th<span class="_ _3"></span>ere is another simulator<span class="_ _3"></span> OPNET which requires <span class="_ _3"></span>licence. </div><div class="t m0 x1 h3 y1d ff2 fs1 fc0 sc0 ls5 ws14">T<span class="_ _4"></span>able 1 [4] compares the wireless p<span class="_ _3"></span>hysical models used in the<span class="_ _3"></span> three simulators. <span class="_"> </span> </div><div class="t m0 x1 h3 y1e ff2 fs1 fc0 sc0 ls4 ws3"> </div><div class="t m0 x1 h3 y1f ff2 fs1 fc0 sc0 ls4 ws3"> </div><div class="t m0 x1 h3 y20 ff2 fs1 fc0 sc0 ls4 ws3"> </div><div class="t m0 x1 h3 y21 ff2 fs1 fc0 sc0 ls4 ws3"> </div><div class="t m0 x1 h3 y22 ff2 fs1 fc0 sc0 ls4 ws3"> </div><div class="t m0 x1 h3 y23 ff2 fs1 fc0 sc0 ls4 ws3"> </div></div><div class="pi" data-data='{"ctm":[1.611639,0.000000,0.000000,1.611639,0.000000,0.000000]}'></div></div> </body> </html>
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