Multi-Carrier_PAP_Reduction.rar

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OFDM的一个多载波峰均比降低算法分析,挺好的,希望能与大家同享
Multi-Carrier_PAP_Reduction.rar
  • Multi-Carrier PAP Reduction Method Using Sub-Optimal PTS With Threshold.pdf
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内容介绍
<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/6243d19e0cf57275afa01c39/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/6243d19e0cf57275afa01c39/bg1.jpg"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls0 ws0">232<span class="_ _0"> </span>IEEE<span class="_"> </span>TRANSACTIONS<span class="_"> </span>ON<span class="_ _1"> </span>BR<span class="_ _2"></span>OADCASTING,<span class="_"> </span>V<span class="_ _2"></span>OL.<span class="_"> </span>49,<span class="_ _1"> </span>NO.<span class="_ _1"> </span>2,<span class="_"> </span>JUNE<span class="_ _1"> </span>2003</div><div class="t m0 x2 h3 y2 ff1 fs1 fc0 sc0 ls0 ws0">Multi-Carrier<span class="_"> </span>P<span class="_ _3"></span>AP<span class="_"> </span>Reduction<span class="_"> </span>Method<span class="_"> </span>Using<span class="_"> </span>Sub-Optimal<span class="_"> </span>PTS<span class="_"> </span>W<span class="_ _4"></span>ith<span class="_"> </span>Threshold</div><div class="t m0 x3 h4 y3 ff1 fs2 fc0 sc0 ls0 ws0">Oh-Ju<span class="_ _5"> </span>Kwon<span class="_"> </span>and<span class="_ _5"> </span>Y<span class="_ _6"></span>eong-Ho<span class="_ _5"> </span>Ha<span class="ff2">,<span class="_"> </span>Senior<span class="_ _5"> </span>Member<span class="_ _6"></span>,<span class="_"> </span>IEEE</span></div><div class="t m0 x4 h5 y4 ff3 fs3 fc0 sc0 ls0 ws0">Abstract&#8212;<span class="ff4">This<span class="_ _7"> </span>paper<span class="_ _7"> </span>presents<span class="_ _7"> </span>an<span class="_ _7"> </span>orthogonal<span class="_ _7"> </span>fr<span class="_ _4"></span>equency<span class="_ _7"> </span>di-</span></div><div class="t m0 x1 h5 y5 ff4 fs3 fc0 sc0 ls0 ws0">vision<span class="_ _8"> </span>multiplexing<span class="_ _8"> </span>(OFDM)<span class="_ _8"> </span>system,<span class="_ _8"> </span>which<span class="_ _8"> </span>through<span class="_ _8"> </span>the<span class="_ _8"> </span>use<span class="_ _8"> </span>of</div><div class="t m0 x1 h5 y6 ff4 fs3 fc0 sc0 ls0 ws0">sub-optimal<span class="_ _5"> </span>PTS<span class="_ _9"> </span>combined<span class="_ _9"> </span>with<span class="_ _5"> </span>a<span class="_ _9"> </span>preset<span class="_ _5"> </span>thr<span class="_ _2"></span>eshold,<span class="_ _9"> </span>achieves<span class="_ _9"> </span>low</div><div class="t m0 x1 h5 y7 ff4 fs3 fc0 sc0 ls0 ws0">computational<span class="_ _a"> </span>complexity<span class="_ _a"> </span>to<span class="_ _5"> </span>find<span class="_ _a"> </span>optimum<span class="_ _a"> </span>weighting<span class="_ _a"> </span>factors.<span class="_ _a"> </span>A</div><div class="t m0 x1 h5 y8 ff4 fs3 fc0 sc0 ls0 ws0">specific<span class="_"> </span>bit<span class="_ _9"> </span>in<span class="_ _9"> </span>weighting<span class="_"> </span>factor<span class="_ _9"> </span>that<span class="_ _9"> </span>leads<span class="_ _9"> </span>to<span class="_"> </span>a<span class="_ _9"> </span>smaller<span class="_ _9"> </span>peak-to-a<span class="_ _2"></span>v-</div><div class="t m0 x1 h5 y9 ff4 fs3 fc0 sc0 ls0 ws0">erage<span class="_ _8"> </span>power<span class="_ _8"> </span>ratio<span class="_ _7"> </span>(</div><div class="t m0 x5 h5 ya ff4 fs3 fc0 sc0 ls0 ws0">)<span class="_ _8"> </span>is<span class="_ _8"> </span>identified<span class="_ _8"> </span>from<span class="_ _8"> </span>the<span class="_ _8"> </span>sub-optimum</div><div class="t m0 x1 h5 yb ff4 fs3 fc0 sc0 ls0 ws0">method.<span class="_ _5"> </span>And<span class="_ _a"> </span>a<span class="_ _5"> </span>specific<span class="_ _5"> </span>threshold,<span class="_ _5"> </span>which<span class="_ _5"> </span>found<span class="_ _5"> </span>from<span class="_ _5"> </span>the<span class="_ _5"> </span>OFDM</div><div class="t m0 x1 h5 yc ff4 fs3 fc0 sc0 ls0 ws0">frame<span class="_ _a"> </span>probability<span class="_ _6"></span>,<span class="_ _a"> </span>is<span class="_ _a"> </span>also<span class="_ _a"> </span>applied<span class="_ _a"> </span>to<span class="_ _5"> </span>reduce<span class="_ _a"> </span>computational<span class="_ _5"> </span>com-</div><div class="t m0 x1 h5 yd ff4 fs3 fc0 sc0 ls0 ws0">plexity<span class="_ _4"></span>.<span class="_ _8"> </span>The<span class="_ _8"> </span>performance<span class="_ _8"> </span>of<span class="_ _8"> </span>the<span class="_ _8"> </span>proposed<span class="_ _8"> </span>method<span class="_ _8"> </span>was<span class="_ _8"> </span>slightly</div><div class="t m0 x1 h5 ye ff4 fs3 fc0 sc0 ls0 ws0">degraded<span class="_ _5"> </span>compared<span class="_ _a"> </span>to<span class="_ _5"> </span>that<span class="_ _a"> </span>of<span class="_ _5"> </span>optimum<span class="_ _a"> </span>method,<span class="_ _a"> </span>PTS.<span class="_ _5"> </span>However<span class="_ _6"></span>,</div><div class="t m0 x1 h5 yf ff4 fs3 fc0 sc0 ls0 ws0">the<span class="_ _8"> </span>complexity<span class="_ _8"> </span>of<span class="_ _8"> </span>the<span class="_ _8"> </span>pr<span class="_ _4"></span>oposed<span class="_ _8"> </span>method<span class="_ _8"> </span>was<span class="_ _8"> </span>remarkably<span class="_ _8"> </span>lower</div><div class="t m0 x1 h5 y10 ff4 fs3 fc0 sc0 ls0 ws0">than<span class="_ _7"> </span>that<span class="_ _7"> </span>of<span class="_ _b"> </span>optimum<span class="_ _7"> </span>method.</div><div class="t m0 x6 h5 y11 ff3 fs3 fc0 sc0 ls0 ws0">Index<span class="_ _c"> </span>T<span class="_ _6"></span>erms&#8212;<span class="ff4">OFDM<span class="_ _c"> </span>system,<span class="_ _c"> </span>peak-to-average<span class="_ _c"></span>po<span class="_ _2"></span>wer<span class="_ _c"> </span>ratio,<span class="_ _c"></span>PTS.</span></div><div class="t m0 x7 h6 y12 ff1 fs4 fc0 sc0 ls0 ws0">I.<span class="_ _d"> </span>I<span class="fs5">NTR<span class="_ _2"></span>ODUCTION</span></div><div class="t m0 x1 h7 y13 ff4 fs6 fc0 sc0 ls0 ws0">C</div><div class="t m0 x8 h6 y14 ff1 fs4 fc0 sc0 ls0 ws0">URRENTL<span class="_ _6"></span>Y<span class="_ _3"></span>,<span class="_"> </span>a<span class="_"> </span>lot<span class="_ _9"> </span>of<span class="_"> </span>attention<span class="_"> </span>is<span class="_ _9"> </span>being<span class="_"> </span>paid<span class="_ _9"> </span>to<span class="_"> </span>multi-car-</div><div class="t m0 x8 h6 y15 ff1 fs4 fc0 sc0 ls0 ws0">rier<span class="_ _e"> </span>modulation<span class="_ _e"> </span>and<span class="_ _e"> </span>orthogonal<span class="_ _e"> </span>frequency<span class="_ _e"> </span>di<span class="_ _2"></span>vision</div><div class="t m0 x1 h6 y16 ff1 fs4 fc0 sc0 ls0 ws0">multiplexing<span class="_ _8"> </span>(OFDM).<span class="_ _7"> </span>OFDM<span class="_ _7"> </span>is<span class="_ _7"> </span>a<span class="_ _7"> </span>multi-carrier<span class="_ _7"> </span>modulation</div><div class="t m0 x1 h6 y17 ff1 fs4 fc0 sc0 ls0 ws0">technique<span class="_ _d"> </span>for<span class="_ _d"> </span>high<span class="_ _f"> </span>data<span class="_ _d"> </span>rate<span class="_ _d"> </span>transmission<span class="_ _f"> </span>in<span class="_ _d"> </span>impulse<span class="_ _d"> </span>noise</div><div class="t m0 x1 h6 y18 ff1 fs4 fc0 sc0 ls0 ws0">and<span class="_ _8"> </span>multi-path<span class="_ _8"> </span>fading<span class="_ _8"> </span>en<span class="_ _4"></span>vironment.<span class="_ _8"> </span>This<span class="_ _8"> </span>technique<span class="_ _8"> </span>has<span class="_ _8"> </span>been</div><div class="t m0 x1 h6 y19 ff1 fs4 fc0 sc0 ls0 ws0">proposed<span class="_ _8"> </span>or<span class="_ _8"> </span>adapted<span class="_ _8"> </span>for<span class="_ _8"> </span>Digital<span class="_ _8"> </span>Audio<span class="_ _10"> </span>Broadcasting<span class="_ _10"> </span>(DAB),</div><div class="t m0 x1 h6 y1a ff1 fs4 fc0 sc0 ls0 ws0">Digital<span class="_ _e"> </span>V<span class="_ _6"></span>ideo<span class="_ _e"> </span>Broadcasting-T<span class="_ _6"></span>errestrial<span class="_ _e"> </span>(D<span class="_ _4"></span>VB-T),<span class="_ _e"> </span>wireless</div><div class="t m0 x1 h6 y1b ff1 fs4 fc0 sc0 ls0 ws0">LANs,<span class="_ _9"> </span>and<span class="_ _9"> </span>a<span class="_ _9"> </span>high<span class="_ _5"> </span>cellular<span class="_"> </span>data<span class="_ _9"> </span>rate<span class="_ _5"> </span>[1].<span class="_"> </span>In<span class="_ _9"> </span>the<span class="_ _5"> </span>OFDM<span class="_"> </span>scheme,</div><div class="t m0 x1 h6 y1c ff1 fs4 fc0 sc0 ls0 ws0">the<span class="_ _a"> </span>symbols<span class="_ _a"> </span>are<span class="_ _a"> </span>transmitted<span class="_ _a"> </span>in<span class="_ _a"> </span>parallel,<span class="_ _a"> </span>and<span class="_ _a"> </span>each<span class="_ _a"> </span>sub-channel</div><div class="t m0 x1 h6 y1d ff1 fs4 fc0 sc0 ls0 ws0">has<span class="_ _a"> </span>a<span class="_ _5"> </span>long<span class="_ _a"> </span>symbol<span class="_ _a"> </span>time,<span class="_ _a"> </span>thus<span class="_ _a"> </span>it<span class="_ _5"> </span>spreads<span class="_ _a"> </span>the<span class="_ _a"> </span>fading<span class="_ _a"> </span>ov<span class="_ _2"></span>er<span class="_ _5"> </span>many</div><div class="t m0 x1 h6 y1e ff1 fs4 fc0 sc0 ls0 ws0">symbols<span class="_ _a"> </span>and<span class="_ _a"> </span>can<span class="_ _10"> </span>immunize<span class="_ _a"> </span>against<span class="_ _a"> </span>some<span class="_ _a"> </span>impulse<span class="_ _a"> </span>noise.<span class="_ _10"> </span>Fur-</div><div class="t m0 x1 h6 y1f ff1 fs4 fc0 sc0 ls0 ws0">thermore,<span class="_ _9"> </span>the<span class="_ _5"> </span>system<span class="_ _9"> </span>can<span class="_ _5"> </span>be<span class="_ _9"> </span>efficiently<span class="_"> </span>implemented<span class="_ _5"> </span>using<span class="_ _9"> </span>the</div><div class="t m0 x1 h6 y20 ff1 fs4 fc0 sc0 ls0 ws0">fast<span class="_ _a"> </span>Fourier<span class="_ _a"> </span>transform<span class="_ _10"> </span>(FFT)<span class="_ _a"> </span>and<span class="_ _10"> </span>the<span class="_ _a"> </span>VLSI<span class="_ _10"> </span>technique<span class="_ _a"> </span>can<span class="_ _a"> </span>re-</div><div class="t m0 x1 h6 y21 ff1 fs4 fc0 sc0 ls0 ws0">duce<span class="_ _9"> </span>implementation<span class="_ _9"> </span>cost.<span class="_ _5"> </span>Ho<span class="_ _2"></span>we<span class="_ _2"></span>ver<span class="_ _4"></span>,<span class="_ _9"> </span>an<span class="_ _9"> </span>OFDM<span class="_ _5"> </span>signal<span class="_ _9"> </span>consists</div><div class="t m0 x1 h6 y22 ff1 fs4 fc0 sc0 ls0 ws0">of<span class="_ _10"> </span>a<span class="_ _10"> </span>number<span class="_ _10"> </span>of<span class="_ _10"> </span>independently<span class="_ _10"> </span>modulated<span class="_ _10"> </span>sub-carriers,<span class="_ _10"> </span>which</div><div class="t m0 x1 h6 y23 ff1 fs4 fc0 sc0 ls0 ws0">can<span class="_ _d"> </span>giv<span class="_ _2"></span>e<span class="_ _d"> </span>a<span class="_ _d"> </span>high<span class="_ _d"> </span>peak-to-average<span class="_ _b"> </span>power<span class="_ _b"> </span>ratio<span class="_ _d"> </span>(</div><div class="t m0 x9 h6 y24 ff1 fs4 fc0 sc0 ls0 ws0">)<span class="_ _d"> </span>when</div><div class="t m0 x1 h6 y25 ff1 fs4 fc0 sc0 ls0 ws0">added<span class="_ _10"> </span>up<span class="_ _a"> </span>coherently<span class="_ _10"> </span>[1]&#8211;[3].<span class="_ _a"> </span>This<span class="_ _10"> </span>high</div><div class="t m0 xa h6 y26 ff1 fs4 fc0 sc0 ls0 ws0">is<span class="_ _10"> </span>signif<span class="_ _4"></span>icantly</div><div class="t m0 x1 h6 y27 ff1 fs4 fc0 sc0 ls0 ws0">more<span class="_ _b"> </span>sensitive<span class="_ _b"> </span>to<span class="_ _d"> </span>nonlinear<span class="_ _d"> </span>distortion,<span class="_ _d"> </span>usually<span class="_ _d"> </span>caused<span class="_ _d"> </span>by<span class="_ _b"> </span>a</div><div class="t m0 x1 h6 y28 ff1 fs4 fc0 sc0 ls0 ws0">high<span class="_"> </span>power<span class="_"> </span>amplifier<span class="_"> </span>(HP<span class="_ _6"></span>A),<span class="_"> </span>than<span class="_ _9"> </span>single<span class="_"> </span>carrier<span class="_ _9"> </span>systems.<span class="_ _9"> </span>Since</div><div class="t m0 x1 h6 y29 ff1 fs4 fc0 sc0 ls0 ws0">this<span class="_ _b"> </span>nonlinear<span class="_ _d"> </span>distortion<span class="_ _d"> </span>generates<span class="_ _d"> </span>inter-symbol<span class="_ _d"> </span>interference</div><div class="t m0 x1 h6 y2a ff1 fs4 fc0 sc0 ls0 ws0">and<span class="_ _11"> </span>inter-modulation,<span class="_ _11"> </span>a<span class="_ _11"> </span>compensating<span class="_ _11"> </span>algorithm<span class="_ _11"> </span>to<span class="_ _f"> </span>reduce</div><div class="t m0 x1 h6 y2b ff1 fs4 fc0 sc0 ls0 ws0">the<span class="_ _10"> </span>nonlinear<span class="_ _8"> </span>distortion<span class="_ _10"> </span>of<span class="_ _8"> </span>an<span class="_ _10"> </span>HP<span class="_ _6"></span>A<span class="_ _8"> </span>is<span class="_ _8"> </span>required.<span class="_ _10"> </span>A<span class="_ _8"> </span>high<span class="_ _10"> </span>back</div><div class="t m0 x1 h6 y2c ff1 fs4 fc0 sc0 ls0 ws0">off<span class="_ _10"> </span>(BO)<span class="_ _8"> </span>can<span class="_ _7"> </span>reduce<span class="_ _8"> </span>the<span class="_ _8"> </span>nonlinear<span class="_ _8"> </span>effects<span class="_ _8"> </span>on<span class="_ _8"> </span>a<span class="_ _8"> </span>multi-carrier</div><div class="t m0 x1 h6 y2d ff1 fs4 fc0 sc0 ls0 ws0">signal,<span class="_ _10"> </span>yet<span class="_ _a"> </span>this<span class="_ _10"> </span>results<span class="_ _a"> </span>in<span class="_ _10"> </span>a<span class="_ _a"> </span>power<span class="_ _a"> </span>ineff<span class="_ _4"></span>icient<span class="_ _10"> </span>operation<span class="_ _a"> </span>of<span class="_ _10"> </span>the</div><div class="t m0 x1 h6 y2e ff1 fs4 fc0 sc0 ls0 ws0">amplifier<span class="_ _6"></span>.<span class="_ _a"> </span>Reducing<span class="_ _a"> </span>the</div><div class="t m0 xb h6 y2f ff1 fs4 fc0 sc0 ls0 ws0">of<span class="_ _a"> </span>OFDM<span class="_ _a"> </span>frame<span class="_ _a"> </span>can<span class="_ _a"> </span>minimize</div><div class="t m0 x1 h6 y30 ff1 fs4 fc0 sc0 ls0 ws0">power<span class="_ _5"> </span>ineff<span class="_ _2"></span>iciency<span class="_ _a"> </span>of<span class="_ _a"> </span>the<span class="_ _a"> </span>amplifier<span class="_ _6"></span>.<span class="_ _a"> </span>In<span class="_ _10"> </span>order<span class="_ _5"> </span>to<span class="_ _10"> </span>reduce<span class="_ _5"> </span>a<span class="_ _10"> </span>high</div><div class="t m0 x8 h6 y31 ff1 fs4 fc0 sc0 ls0 ws0">,<span class="_"> </span>v<span class="_ _2"></span>arious<span class="_"> </span>solutions<span class="_"> </span>ha<span class="_ _2"></span>ve<span class="_"> </span>already<span class="_"> </span>been<span class="_ _1"> </span>proposed,<span class="_"> </span>including</div><div class="t m0 x1 h6 y32 ff1 fs4 fc0 sc0 ls0 ws0">signal<span class="_ _1"> </span>distortion<span class="_"> </span>techniques,<span class="_ _1"> </span>coding<span class="_ _1"> </span>techniques,<span class="_"> </span>and<span class="_ _1"> </span>scrambling</div><div class="t m0 x1 h6 y33 ff1 fs4 fc0 sc0 ls0 ws0">techniques.</div><div class="t m0 xc h6 y34 ff1 fs4 fc0 sc0 ls0 ws0">The<span class="_ _c"> </span>partial<span class="_ _1"> </span>transmit<span class="_ _c"></span>sequence<span class="_ _c"> </span>(PTS)<span class="_ _1"> </span>approach,<span class="_ _c"></span>which<span class="_ _c"></span>is<span class="_ _12"> </span>a<span class="_ _c"> </span>kind</div><div class="t m0 x1 h6 y35 ff1 fs4 fc0 sc0 ls0 ws0">of<span class="_ _12"> </span>scrambling<span class="_ _12"> </span>technique<span class="_ _1"> </span>for<span class="_ _12"> </span>improving<span class="_ _12"> </span>the<span class="_ _12"> </span>statistics<span class="_ _12"> </span>of<span class="_ _1"> </span>the</div><div class="t m0 x1 h6 y36 ff1 fs4 fc0 sc0 ls0 ws0">of<span class="_ _12"> </span>a<span class="_ _1"> </span>multi-carrier<span class="_ _12"> </span>signal,<span class="_ _1"> </span>was<span class="_ _12"> </span>proposed<span class="_ _1"> </span>by<span class="_ _12"> </span>Muller<span class="_ _1"> </span>and<span class="_ _12"> </span>Huber<span class="_ _1"> </span>[4],</div><div class="t m0 x1 h6 y37 ff1 fs4 fc0 sc0 ls0 ws0">[5].<span class="_ _5"> </span>In<span class="_ _5"> </span>PTS,<span class="_ _5"> </span>an<span class="_ _5"> </span>input<span class="_ _5"> </span>OFDM<span class="_ _5"> </span>frame<span class="_ _5"> </span>of</div><div class="t m0 xd h6 y38 ff1 fs4 fc0 sc0 ls0 ws0">sub-carriers<span class="_ _5"> </span>is<span class="_ _5"> </span>parti-</div><div class="t m0 x1 h6 y39 ff1 fs4 fc0 sc0 ls0 ws0">tioned<span class="_ _c"> </span>into</div><div class="t m0 xe h6 y3a ff1 fs4 fc0 sc0 ls0 ws0">sub-blocks.<span class="_ _c"> </span>T<span class="_ _4"></span>o<span class="_ _12"> </span>reduce<span class="_ _c"> </span>the<span class="_ _13"> </span>,<span class="_ _14"> </span>weighting</div><div class="t m0 xf h8 y3b ff1 fs5 fc0 sc0 ls0 ws0">Manuscript<span class="_"> </span>received<span class="_"> </span>September<span class="_"> </span>10,<span class="_"> </span>2002;<span class="_"> </span>revised<span class="_"> </span>March<span class="_"> </span>4,<span class="_"> </span>2003.</div><div class="t m0 xf h8 y3c ff1 fs5 fc0 sc0 ls0 ws0">Digital<span class="_"> </span>Object<span class="_ _1"> </span>Identifier<span class="_"> </span>10.1109/TBC.2003.813648</div><div class="t m0 x10 h6 y4 ff1 fs4 fc0 sc0 ls0 ws0">factors<span class="_ _12"> </span>are<span class="_"> </span>selected<span class="_ _12"> </span>so<span class="_"> </span>that<span class="_ _12"> </span>the<span class="_"> </span>resultant<span class="_ _14"> </span>is<span class="_ _12"> </span>minimized.<span class="_"> </span>Y<span class="_ _3"></span>et</div><div class="t m0 x10 h6 y3d ff1 fs4 fc0 sc0 ls0 ws0">finding<span class="_ _5"> </span>the<span class="_ _a"> </span>best<span class="_ _a"> </span>weighting<span class="_ _a"> </span>factors<span class="_ _a"> </span>is<span class="_ _a"> </span>a<span class="_ _a"> </span>complex<span class="_ _a"> </span>and<span class="_ _a"> </span>diff<span class="_ _4"></span>iculty</div><div class="t m0 x10 h6 y3e ff1 fs4 fc0 sc0 ls0 ws0">problem.<span class="_ _1"> </span>T<span class="_ _4"></span>o<span class="_ _1"> </span>obtain<span class="_"> </span>the<span class="_ _1"> </span>optimal<span class="_"> </span>weighting<span class="_ _1"> </span>factors<span class="_"> </span>for<span class="_ _12"> </span>each<span class="_"> </span>input</div><div class="t m0 x10 h6 y3f ff1 fs4 fc0 sc0 ls0 ws0">data<span class="_"> </span>frame,<span class="_"> </span>2</div><div class="t m0 x11 h6 y40 ff1 fs4 fc0 sc0 ls0 ws0">combinations<span class="_"> </span>are<span class="_"> </span>checked<span class="_"> </span>to<span class="_"> </span>obtain<span class="_"> </span>the<span class="_"> </span>min-</div><div class="t m0 x10 h6 y41 ff1 fs4 fc0 sc0 ls0 ws0">imum</div><div class="t m0 x12 h6 y42 ff1 fs4 fc0 sc0 ls0 ws0">.<span class="_"> </span>Some<span class="_"> </span>research<span class="_"> </span>has<span class="_"> </span>already<span class="_ _9"> </span>been<span class="_"> </span>conducted<span class="_"> </span>on<span class="_ _9"> </span>re-</div><div class="t m0 x10 h6 y43 ff1 fs4 fc0 sc0 ls0 ws0">ducing<span class="_ _a"> </span>computation<span class="_ _a"> </span>complexity:<span class="_ _5"> </span>the<span class="_ _10"> </span>iterati<span class="_ _4"></span>ve<span class="_ _a"> </span>flipping<span class="_ _a"> </span>method</div><div class="t m0 x10 h6 y44 ff1 fs4 fc0 sc0 ls0 ws0">[6]<span class="_ _9"> </span>and<span class="_ _9"> </span>adaptiv<span class="_ _2"></span>e<span class="_"> </span>PTS<span class="_ _5"> </span>approach<span class="_"> </span>[7].</div><div class="t m0 x13 h6 y45 ff1 fs4 fc0 sc0 ls0 ws0">This<span class="_ _5"> </span>paper<span class="_ _a"> </span>presents<span class="_ _a"> </span>the<span class="_ _a"> </span>sub-optimal<span class="_ _a"> </span>weighting<span class="_ _a"> </span>factor<span class="_ _5"> </span>to<span class="_ _a"> </span>re-</div><div class="t m0 x10 h6 y46 ff1 fs4 fc0 sc0 ls0 ws0">duce<span class="_ _5"> </span>high</div><div class="t m0 x14 h6 y47 ff1 fs4 fc0 sc0 ls0 ws0">and<span class="_ _5"> </span>computational<span class="_ _9"> </span>complexity<span class="_ _4"></span>.<span class="_ _9"> </span>Several</div><div class="t m0 x10 h6 y48 ff1 fs4 fc0 sc0 ls0 ws0">reduction<span class="_ _7"> </span>methods<span class="_ _7"> </span>have<span class="_ _8"> </span>been<span class="_ _b"> </span>already<span class="_ _7"> </span>proposed<span class="_ _b"> </span>[4],<span class="_ _7"> </span>[6]<span class="_ _7"> </span>and</div><div class="t m0 x10 h6 y49 ff1 fs4 fc0 sc0 ls0 ws0">[7].<span class="_"> </span>Howe<span class="_ _4"></span>ver<span class="_ _4"></span>,<span class="_"> </span>none<span class="_ _9"> </span>of<span class="_"> </span>these<span class="_"> </span>can<span class="_ _9"> </span>simultaneously<span class="_"> </span>propose<span class="_"> </span>a<span class="_ _9"> </span>high</div><div class="t m0 x10 h6 y4a ff1 fs4 fc0 sc0 ls0 ws0">performance<span class="_ _10"> </span>and<span class="_ _a"> </span>low<span class="_ _a"> </span>complexity<span class="_ _10"> </span>result,<span class="_ _a"> </span>which<span class="_ _10"> </span>find<span class="_ _a"> </span>optimum</div><div class="t m0 x10 h6 y4b ff1 fs4 fc0 sc0 ls0 ws0">weighting<span class="_ _10"> </span>factors.<span class="_ _10"> </span>The<span class="_ _10"> </span>sub-optimal<span class="_ _10"> </span>PTS<span class="_ _10"> </span>method<span class="_ _10"> </span>proposed<span class="_ _10"> </span>in</div><div class="t m0 x10 h6 y4c ff1 fs4 fc0 sc0 ls0 ws0">the<span class="_ _a"> </span>current<span class="_ _5"> </span>study<span class="_ _a"> </span>emphasizes<span class="_ _a"> </span>specific<span class="_ _a"> </span>bits<span class="_ _a"> </span>in<span class="_ _5"> </span>weighting<span class="_ _a"> </span>factor</div><div class="t m0 x10 h6 y4d ff1 fs4 fc0 sc0 ls0 ws0">that<span class="_ _1"> </span>leads<span class="_ _1"> </span>to<span class="_"> </span>a<span class="_ _12"> </span>smaller</div><div class="t m0 x15 h6 y4e ff1 fs4 fc0 sc0 ls0 ws0">and<span class="_ _1"> </span>a<span class="_ _1"> </span>threshold,<span class="_ _1"> </span>which<span class="_"> </span>comes<span class="_ _12"> </span>from</div><div class="t m0 x10 h6 y4f ff1 fs4 fc0 sc0 ls0 ws0">Complementary<span class="_ _15"> </span>Cumulativ<span class="_ _4"></span>e<span class="_ _15"> </span>Distribution<span class="_ _15"> </span>Function<span class="_ _15"> </span>(CCDF)</div><div class="t m0 x10 h6 y50 ff1 fs4 fc0 sc0 ls0 ws0">and<span class="_ _8"> </span>terminates<span class="_ _8"> </span>weighting<span class="_ _7"> </span>factor<span class="_ _8"> </span>optimization<span class="_ _8"> </span>as<span class="_ _7"> </span>soon<span class="_ _8"> </span>as<span class="_ _7"> </span>the</div><div class="t m0 x16 h6 y51 ff1 fs4 fc0 sc0 ls0 ws0">of<span class="_"> </span>an<span class="_ _9"> </span>OFDM<span class="_ _9"> </span>frame<span class="_"> </span>is<span class="_ _9"> </span>below<span class="_"> </span>threshold.</div><div class="t m0 x13 h6 y52 ff1 fs4 fc0 sc0 ls0 ws0">This<span class="_ _11"> </span>paper<span class="_ _15"> </span>is<span class="_ _11"> </span>organized<span class="_ _11"> </span>as<span class="_ _15"> </span>follo<span class="_ _2"></span>ws:<span class="_ _11"> </span>Section<span class="_ _15"> </span>II<span class="_ _11"> </span>reviews</div><div class="t m0 x10 h6 y53 ff1 fs4 fc0 sc0 ls0 ws0">characteristics<span class="_ _5"> </span>of<span class="_ _a"> </span>OFDM<span class="_ _5"> </span>signals<span class="_ _a"> </span>and<span class="_ _5"> </span>existing</div><div class="t m0 x17 h6 y54 ff1 fs4 fc0 sc0 ls0 ws0">reduction</div><div class="t m0 x10 h6 y55 ff1 fs4 fc0 sc0 ls0 ws0">methods.<span class="_ _9"> </span>Section<span class="_ _9"> </span>III,<span class="_ _9"> </span>introduces<span class="_ _9"> </span>the<span class="_ _9"> </span>proposed<span class="_ _5"> </span>weighting<span class="_"> </span>factor</div><div class="t m0 x10 h6 y56 ff1 fs4 fc0 sc0 ls0 ws0">method<span class="_ _f"> </span>using<span class="_ _f"> </span>threshold<span class="_ _f"> </span>operation.<span class="_ _f"> </span>Section<span class="_ _f"> </span>IV<span class="_ _f"> </span>presents<span class="_ _f"> </span>the</div><div class="t m0 x10 h6 y57 ff1 fs4 fc0 sc0 ls0 ws0">experimental<span class="_ _9"> </span>results.</div><div class="t m0 x18 h6 y58 ff1 fs4 fc0 sc0 ls0 ws0">II.</div><div class="t m0 x19 h6 y59 ff1 fs4 fc0 sc0 ls0 ws0">R<span class="fs5">EDUCTION<span class="_ _9"> </span></span>M<span class="fs5">ETHOD</span></div><div class="t m0 x10 h9 y5a ff2 fs4 fc0 sc0 ls0 ws0">A.<span class="_ _b"> </span>Characteristics<span class="_ _9"> </span>of<span class="_ _9"> </span>OFDM<span class="_ _9"> </span>Signal</div><div class="t m0 x13 h6 y5b ff1 fs4 fc0 sc0 ls0 ws0">The<span class="_ _10"> </span>characteristic<span class="_ _10"> </span>of<span class="_ _10"> </span>the<span class="_ _10"> </span>OFDM<span class="_ _10"> </span>signal<span class="_ _10"> </span>is<span class="_ _8"> </span>important<span class="_ _10"> </span>infor-</div><div class="t m0 x10 h6 y5c ff1 fs4 fc0 sc0 ls0 ws0">mation<span class="_ _10"> </span>to<span class="_ _7"> </span>minimize</div><div class="t m0 x1a h6 y5d ff1 fs4 fc0 sc0 ls0 ws0">.<span class="_ _8"> </span>Because<span class="_ _8"> </span>the<span class="_ _16"> </span>of<span class="_ _10"> </span>an<span class="_ _8"> </span>OFDM</div><div class="t m0 x10 h6 y5e ff1 fs4 fc0 sc0 ls0 ws0">system<span class="_ _a"> </span>varies<span class="_ _a"> </span>symbol<span class="_ _10"> </span>by<span class="_ _a"> </span>symbol,<span class="_ _10"> </span>the</div><div class="t m0 x1b h6 y5f ff1 fs4 fc0 sc0 ls0 ws0">performance<span class="_ _a"> </span>can</div><div class="t m0 x10 h6 y60 ff1 fs4 fc0 sc0 ls0 ws0">be<span class="_ _5"> </span>expressed<span class="_ _5"> </span>by<span class="_ _a"> </span>the<span class="_ _5"> </span>probability<span class="_ _4"></span>,<span class="_ _5"> </span>i.e.,<span class="_ _a"> </span>a<span class="_ _5"> </span>cumulative<span class="_ _5"> </span>distribution</div><div class="t m0 x10 h6 y61 ff1 fs4 fc0 sc0 ls0 ws0">function<span class="_ _9"> </span>(CDF),<span class="_ _9"> </span>that<span class="_ _9"> </span>the</div><div class="t m0 x1c h6 y62 ff1 fs4 fc0 sc0 ls0 ws0">will<span class="_ _9"> </span>exceed<span class="_"> </span>a<span class="_ _5"> </span>certain<span class="_"> </span>threshold.</div><div class="t m0 x10 h6 y63 ff1 fs4 fc0 sc0 ls0 ws0">The<span class="_ _12"> </span>OFDM<span class="_ _1"> </span>complex<span class="_ _12"> </span>base-band<span class="_ _12"> </span>signal<span class="_ _1"> </span>for</div><div class="t m0 x1d h6 y64 ff1 fs4 fc0 sc0 ls0 ws0">sub-carriers<span class="_ _12"> </span>can<span class="_ _1"> </span>be</div><div class="t m0 x10 h6 y65 ff1 fs4 fc0 sc0 ls0 ws0">written<span class="_ _5"> </span>as:</div><div class="t m0 x1e h6 y66 ff1 fs4 fc0 sc0 ls0 ws0">(1)</div><div class="t m0 x10 h6 y67 ff1 fs4 fc0 sc0 ls0 ws0">where</div><div class="t m0 x1f h6 y68 ff1 fs4 fc0 sc0 ls0 ws0">and<span class="_ _17"> </span>are<span class="_ _10"> </span>the<span class="_ _10"> </span>in-phase<span class="_ _a"> </span>and<span class="_ _10"> </span>amplitude<span class="_ _10"> </span>modulating</div><div class="t m0 x10 h6 y69 ff1 fs4 fc0 sc0 ls0 ws0">symbols.<span class="_ _1"> </span>From<span class="_"> </span>the<span class="_ _12"> </span>central<span class="_"> </span>limit<span class="_ _12"> </span>theorem<span class="_"> </span>it<span class="_ _12"> </span>follows<span class="_ _1"> </span>that<span class="_ _1"> </span>for<span class="_"> </span>lar<span class="_ _4"></span>ge</div><div class="t m0 x10 h6 y6a ff1 fs4 fc0 sc0 ls0 ws0">values<span class="_ _10"> </span>of</div><div class="t m0 x20 h6 y6b ff1 fs4 fc0 sc0 ls0 ws0">,<span class="_ _8"> </span>the<span class="_ _8"> </span>real<span class="_ _8"> </span>and<span class="_ _7"> </span>imaginary<span class="_ _8"> </span>values<span class="_ _10"> </span>of<span class="_ _18"> </span>become</div><div class="t m0 x10 h6 y6c ff1 fs4 fc0 sc0 ls0 ws0">Gaussian<span class="_ _9"> </span>distributed.</div><div class="t m0 x13 h6 y6d ff1 fs4 fc0 sc0 ls0 ws0">The<span class="_ _9"> </span>power<span class="_ _9"> </span>distribution<span class="_ _9"> </span>of<span class="_ _5"> </span>the<span class="_ _9"> </span>OFDM<span class="_ _5"> </span>signal<span class="_ _5"> </span>is<span class="_ _9"> </span>expressed<span class="_ _9"> </span>by</div><div class="t m0 x21 h6 y6e ff1 fs4 fc0 sc0 ls0 ws0">,<span class="_ _a"> </span>where<span class="_ _19"> </span>and<span class="_ _19"> </span>are<span class="_ _a"> </span>the<span class="_ _a"> </span>statistically<span class="_ _10"> </span>inde-</div><div class="t m0 x10 h6 y6f ff1 fs4 fc0 sc0 ls0 ws0">pendent<span class="_ _5"> </span>Gaussian<span class="_ _a"> </span>random<span class="_ _a"> </span>variables<span class="_ _5"> </span>of<span class="_ _5"> </span>the<span class="_ _a"> </span>real<span class="_ _a"> </span>and<span class="_ _5"> </span>imaginary</div><div class="t m0 x10 h6 y70 ff1 fs4 fc0 sc0 ls0 ws0">values<span class="_ _5"> </span>of<span class="_ _5"> </span>the<span class="_ _5"> </span>OFDM<span class="_ _5"> </span>signal,<span class="_ _a"> </span>respectiv<span class="_ _4"></span>ely<span class="_ _4"></span>,<span class="_ _a"> </span>and</div><div class="t m0 x22 h6 y71 ff1 fs4 fc0 sc0 ls0 ws0">is<span class="_ _5"> </span>the<span class="_ _5"> </span>central</div><div class="t m0 x10 h6 y72 ff1 fs4 fc0 sc0 ls0 ws0">chi-square<span class="_ _a"> </span>distribution<span class="_ _5"> </span>with<span class="_ _10"> </span>tw<span class="_ _2"></span>o<span class="_ _a"> </span>degrees<span class="_ _a"> </span>of<span class="_ _a"> </span>freedom<span class="_ _a"> </span>and<span class="_ _a"> </span>zero</div><div class="t m0 x10 h6 y73 ff1 fs4 fc0 sc0 ls0 ws0">mean.<span class="_ _5"> </span>Hence,<span class="_ _5"> </span>the<span class="_ _a"> </span>corresponding<span class="_ _5"> </span>cumulativ<span class="_ _2"></span>e<span class="_ _5"> </span>distribution<span class="_ _5"> </span>func-</div><div class="t m0 x10 h6 y74 ff1 fs4 fc0 sc0 ls0 ws0">tion<span class="_ _9"> </span>of</div><div class="t m0 x23 h6 y75 ff1 fs4 fc0 sc0 ls0 ws0">can<span class="_ _9"> </span>be<span class="_ _5"> </span>written<span class="_"> </span>as:</div><div class="t m0 x1e h6 y76 ff1 fs4 fc0 sc0 ls0 ws0">(2)</div><div class="t m0 x24 h8 y77 ff1 fs5 fc0 sc0 ls0 ws0">0018-9316/03$17.00<span class="_ _1a"> </span>&#169;<span class="_ _1a"> </span>2003<span class="_ _1"> </span>IEEE</div><div class="t m0 x25 ha y78 ff5 fs7 fc0 sc0 ls0 ws0"><span class="fc1 sc0">Authorized licensed use limited to: Xian Jiaotong University. Downloaded on March 13,2010 at 21:37:41 EST from IEEE Xplore. Restrictions apply. </span></div><div class="d m1"></div><div class="d m1"></div><div class="d m1"></div><div class="d m1"></div><div class="d m1"></div><div class="d m1"></div><div class="d m1"></div><div class="d m1"></div><div class="d m1"></div><div class="d m1"></div></div><div class="pi" data-data='{"ctm":[1.568627,0.000000,0.000000,1.568627,0.000000,0.000000]}'></div></div> </body> </html>
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