[31] | 1 | /************************************************************************************ |
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| 2 | * Copyright (C) 2008 by Politehnica University of Bucharest and Rutgers University |
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| 3 | * All rights reserved. |
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| 4 | * Refer to LICENSE for terms and conditions of use. |
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| 5 | ***********************************************************************************/ |
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| 6 | //Petroaca - two ray propagation model |
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| 7 | package vnsim.network.propagation; |
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| 8 | |
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| 9 | import vnsim.map.object.Globals; |
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| 10 | import vnsim.network.propagation.FreeSpace; |
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| 11 | |
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| 12 | public class TwoRay |
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| 13 | { |
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| 14 | private static double Hr=Globals.AH; |
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| 15 | private static double Ht=Globals.AH; |
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| 16 | private static double crossoverDistance=(4*Math.PI*Ht*Hr)/Globals.DSRC_LAMBDA; |
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| 17 | |
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| 18 | public static double getPr(double Pt,double R) |
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| 19 | { |
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| 20 | if(Pt<=0.0 || R<=0.0) |
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| 21 | return -1; |
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| 22 | |
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| 23 | if(R<=crossoverDistance) |
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| 24 | { |
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| 25 | return FreeSpace.getPr(Pt,R); |
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| 26 | } |
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| 27 | else |
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| 28 | { |
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| 29 | double aux=Math.pow(Ht,2)*Math.pow(Hr,2); |
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| 30 | double R4=Math.pow(R,4); |
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| 31 | |
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| 32 | return (Pt*Math.pow(Globals.ANTENNA_GAIN,2)*aux)/(R4*Globals.SYSTEM_LOSS); |
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| 33 | } |
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| 34 | } |
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| 35 | |
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| 36 | public static double getPrAlt(double Pt,double R) |
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| 37 | { |
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| 38 | if(Pt<=0 || R<=0) |
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| 39 | return -1; |
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| 40 | |
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| 41 | double pathloss = -(2*Globals.ANTENNA_GAIN); |
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| 42 | double freeSpace = (4.0 * Math.PI * R) / Globals.DSRC_LAMBDA; |
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| 43 | double planeEarth = (R * R) / (Hr*Ht); |
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| 44 | |
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| 45 | if (planeEarth > freeSpace){ |
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| 46 | pathloss += 20.0 * Math.log10(planeEarth); |
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| 47 | }else{ |
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| 48 | pathloss += 20.0 * Math.log10(freeSpace); |
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| 49 | } |
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| 50 | |
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| 51 | return Pt-pathloss; |
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| 52 | } |
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| 53 | } |
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