propagation.cc

fso antenna model for ns2

/* -*-	Mode:C++; c-basic-offset:8; tab-width:8; indent-tabs-mode:t -*- */
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 *    must display the following acknowledgement:
 *	This product includes software developed by the Computer Systems
 *	Engineering Group at Lawrence Berkeley Laboratory.
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 propagation.cc
 $Id: propagation.cc,v 1.7 2005/02/03 20:15:00 haldar Exp $
*/

#include <stdio.h>

#include <topography.h>
#include <propagation.h>
#include <wireless-phy.h>
#include <fso/fso-antenna.h>

class PacketStamp;
int
Propagation::command(int argc, const char*const* argv)
{
  TclObject *obj;  

  if(argc == 3) 
    {
      if( (obj = TclObject::lookup(argv[2])) == 0) 
	{
	  fprintf(stderr, "Propagation: %s lookup of %s failed\n", argv[1],
		  argv[2]);
	  return TCL_ERROR;
	}

      if (strcasecmp(argv[1], "topography") == 0) 
	{
	  topo = (Topography*) obj;
	  return TCL_OK;
	}
    }
  return TclObject::command(argc,argv);
}
 

/* As new network-intefaces are added, add a default method here */

double
Propagation::Pr(PacketStamp *, PacketStamp *, Phy *)
{
	fprintf(stderr,"Propagation model %s not implemented for generic NetIF\n",
	  name);
	abort();
	return 0; // Make msvc happy
}


double
Propagation::Pr(PacketStamp *, PacketStamp *, WirelessPhy *)
{
	fprintf(stderr,
		"Propagation model %s not implemented for SharedMedia interface\n",
		name);
	abort();
	return 0; // Make msvc happy
}

double
Propagation::getDist(double Pr, double Pt, double Gt, double Gr, double hr,
		     double ht, double L, double lambda)
{
	fprintf(stderr,
		"Propagtion model %s not implemented for generic use\n", name);
	abort();
	return 0;
}

double
Propagation::Friis(double Pt, double Gt, double Gr, double lambda, double L, double d)
{
        /*
         * Friis free space equation:
         *
         *       Pt * Gt * Gr * (lambda^2)
         *   P = --------------------------
         *       (4 * pi * d)^2 * L
         */
	if (d == 0.0) //XXX probably better check < MIN_DISTANCE or some such
		return Pt;
  double M = lambda / (4 * PI * d);
  return (Pt * Gt * Gr * (M * M)) / L;
}


// methods for free space model
static class FreeSpaceClass: public TclClass {
public:
	FreeSpaceClass() : TclClass("Propagation/FreeSpace") {}
	TclObject* create(int, const char*const*) {
		return (new FreeSpace);
	}
} class_freespace;


double FreeSpace::Pr(PacketStamp *t, PacketStamp *r, WirelessPhy *ifp)
{
	double L = ifp->getL();		// system loss
	double lambda = ifp->getLambda();   // wavelength

	double Xt, Yt, Zt;		// location of transmitter
	double Xr, Yr, Zr;		// location of receiver

	t->getNode()->getLoc(&Xt, &Yt, &Zt);
	r->getNode()->getLoc(&Xr, &Yr, &Zr);

	// Is antenna position relative to node position?
	Xr += r->getAntenna()->getX();
	Yr += r->getAntenna()->getY();
	Zr += r->getAntenna()->getZ();
	Xt += t->getAntenna()->getX();
	Yt += t->getAntenna()->getY();
	Zt += t->getAntenna()->getZ();

	double dX = Xr - Xt;
	double dY = Yr - Yt;
	double dZ = Zr - Zt;
	double d = sqrt(dX * dX + dY * dY + dZ * dZ);

	// get antenna gain
	double Gt = t->getAntenna()->getTxGain(dX, dY, dZ, lambda);
	double Gr = r->getAntenna()->getRxGain(dX, dY, dZ, lambda);

	// calculate receiving power at distance
	double Pr = Friis(t->getTxPr(), Gt, Gr, lambda, L, d);
	printf("%lf: d: %lf, Pr: %e\n", Scheduler::instance().clock(), d, Pr);

	return Pr;
}

double
FreeSpace::getDist(double Pr, double Pt, double Gt, double Gr, double hr, double ht, double L, double lambda)
{
        return sqrt((Pt * Gt * Gr * lambda * lambda) / (L * Pr)) /
                (4 * PI);
}

// begin RPI FSO Extensions

// methods for free space model
static class FreeSpaceOpticalClass: public TclClass {
public:
	FreeSpaceOpticalClass() : TclClass("Propagation/FreeSpaceOptical") {}
	TclObject* create(int, const char*const*) {
		return (new FreeSpaceOptical);
	}
} class_freespaceoptical;


double FreeSpaceOptical::Pr(PacketStamp *t, PacketStamp *r, WirelessPhy *ifp)
{
	long double Visibility; /* Visibility of the weather in KM*/
	long double Lambda; /*The wavelength of the light transmitted in Nano meters*/

	double power_from_node = 0.0;
	
	FSOAntenna * Current_Receiver =  (FSOAntenna *)r->getAntenna();
	FSOAntenna * Current_Transmitter = (FSOAntenna *)t->getAntenna();
	
	Visibility =  ifp->getVisibility();
	
	Lambda =  ifp->getLambda();
	
	power_from_node = Power(
				Current_Receiver, Current_Transmitter, 
				Visibility, 
				Lambda
				);
	
	
	return power_from_node;
}

double FreeSpaceOptical::Power(FSOAntenna * CurrentAntenna, FSOAntenna * OtherAntenna, double visibility, double lambda)
   {

     
	/* This is the propagation model for the FSO link Here we calculate the loss due to propagaton,*/ 
	/*and find the power at the recevier based on the distance and visibility*/
	
	/* Transmitter parameters*/
	long double Tx_Power; /* The transmitted power in Decibels*/
	long double Tx_Angle; /* half included angle in milliradians*/
	//long double Area_transmitter; /* Area of the transmitter/LED*/
	long double Dia_Transmitter; /* Diameter of the transmitter/LED in Centimeters*/
	
	/*Receiver Parameters*/
	long double Rc_Sensitivity; /* In decibels*/
	long double Dia_Receiver; /*In Centimeters*/ 
	long double Rx_Angle;
	long double Roe;
	
	/* Received Power */
	long double Rx_Power_ = 0.0 ;
	/* Geometrical loss parameters*/
	long double Geometrical_Loss;
	long double Loss_Angle;
	
	/*Atmospheric loss paramters*/
	
	long double particle_size; /*Calc:The size distribution of the scattering particles*/
	long double Atmospheric_Loss;//calc
	long double sigma;//calc
	
	/*Total Loss*/
	long double Loss;
	
	/* The angular orientation of the receiver */
	long double theta; /*Angle between NLOS of antenna1 and R (To be found out)*/
	long double phi;/*Angle between NLOS of antenna2 and R (To be found out)*/
	/*R is the Vector between the receiver from the transmitter*/
	long double Mod_R; /*Absolute distance between Tx and Rx*/
	long double Mod_NLOS1; /*Absolute length of the NLOS1*/
	long double Mod_NLOS2; /*Absolute length of NLOS2*/
	long double Z; /* Distance of the receiver from transmitter if theta were zero (0)*/
	
	
	/* Co-ordinates of both the communicating antennas and their NLOS's*/
	long double XAntenna1_CoOrd;
	long double YAntenna1_CoOrd;
	long double ZAntenna1_CoOrd; 
	long double XAntenna2_CoOrd; 
	long double YAntenna2_CoOrd; 
	long double ZAntenna2_CoOrd; 
	long double X_NLOS1;
	long double Y_NLOS1;
	long double Z_NLOS1;
	long double X_NLOS2;
	long double Y_NLOS2; 
	long double Z_NLOS2;
	
	XAntenna1_CoOrd = CurrentAntenna->getX();
	YAntenna1_CoOrd = CurrentAntenna->getY();
	ZAntenna1_CoOrd = CurrentAntenna->getZ();
	XAntenna2_CoOrd = OtherAntenna->getX();
	YAntenna2_CoOrd = OtherAntenna->getY();
	ZAntenna2_CoOrd = OtherAntenna->getZ();
	X_NLOS1 = CurrentAntenna->getXNormal();
	Y_NLOS1 = CurrentAntenna->getYNormal();
	Z_NLOS1 = CurrentAntenna->getZNormal();
	X_NLOS2 = OtherAntenna->getXNormal();
	Y_NLOS2 = OtherAntenna->getYNormal();
	Z_NLOS2 = OtherAntenna->getZNormal();
	
	Tx_Power = OtherAntenna->getTx_Power();
	Tx_Angle = OtherAntenna->getTx_Angle();
	Dia_Transmitter = OtherAntenna->getTx_Dia();
	
	Rc_Sensitivity =  CurrentAntenna->getRx_Sensitivity();
	Rx_Angle = CurrentAntenna->getRx_Angle();
	Dia_Receiver = CurrentAntenna->getRx_Dia();
	
	/*Get the LOS distance from the co-orinates*/
	
	Mod_R = sqrt(square(XAntenna2_CoOrd - XAntenna1_CoOrd) + square(YAntenna2_CoOrd - YAntenna1_CoOrd) + square(ZAntenna2_CoOrd - ZAntenna1_CoOrd));
	
	Mod_NLOS1 =  sqrt(square(X_NLOS1) + square(Y_NLOS1) + square(Z_NLOS1));
	Mod_NLOS2 =  sqrt(square(X_NLOS2) + square(Y_NLOS2) + square(Z_NLOS2));

	Roe = ((XAntenna2_CoOrd - XAntenna1_CoOrd)*X_NLOS1 + (YAntenna2_CoOrd - YAntenna1_CoOrd)*Y_NLOS1 + (ZAntenna2_CoOrd - ZAntenna1_CoOrd)*Z_NLOS1)/(Mod_R * Mod_NLOS1);

	if(Roe < -1)
	{
		theta = PI;
	}
	else if(Roe > 1)
	{
		theta = 0.0;
	}
	else
	{
		theta = acos(Roe);
	}
	
	Z = Mod_R/cos(theta);

	/* R taken in the opposite direction*/

	Roe = ((XAntenna1_CoOrd - XAntenna2_CoOrd)*X_NLOS2 + (YAntenna1_CoOrd - YAntenna2_CoOrd)*Y_NLOS2 + (ZAntenna1_CoOrd - ZAntenna2_CoOrd)*Z_NLOS2)/(Mod_R * Mod_NLOS2);

	if(Roe < -1)
	{
		phi = PI;
	}
	else if(Roe > 1)
	{
		phi = 0.0;
	}
	else
	{
		phi = acos(Roe);
	}

	Loss_Angle = pow(cos(phi), 10);
	
	/* Now check for the angular orientation of the receiver*/  
	/* If the receiver is exacly in line of sight, then the received power is the above*/
	
	/*DAVID: This code is to be used once the co-ordinates of both antennas (recevier and sender): AJ*/

	if(theta < (Rx_Angle/2.0) && phi < (Tx_Angle/2.0))
	{
		/*Antennas are aligned*/
		/* Geometricla Loss*/
		Geometrical_Loss = Dia_Receiver/(Dia_Transmitter + 100*Mod_R*Tx_Angle);
		
		/* The SECOND component is due to the atmospheric attenuation*/
		/* The size distribution of the scattering particles*/
		if(visibility > 50)
			particle_size = 1.6;
		if((visibility <= 50) && (visibility > 6))
			particle_size = 1.3;
		if(visibility <= 6)
			particle_size = 0.585*pow(visibility, 1/3);
		
		/* The attenuation co-efficient  sigma*/
		sigma = (3.91/visibility)*pow((long double)lambda/550e-9, -(particle_size));
		
		Atmospheric_Loss = exp(-(sigma*(Mod_R)));
		/*Total Loss is the sum of both losses*/
		Loss =  Geometrical_Loss;
		
		/* The power at the receiver*/
		Rx_Power_ = (Tx_Power + Loss) * pow(cos(theta),15) * pow(cos(phi),15);

		return Rx_Power_;
	}
	else
	{
		return 0.0;
	}
}

double
FreeSpaceOptical::getDist(double Pr, double Pt, double Gt, double Gr, double hr, double ht, double L, double lambda)
{
        return sqrt((Pt * Gt * Gr * lambda * lambda) / (L * Pr)) /
                (4 * PI);
}

// end RPI FSO Extensions