/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
/*
* Copyright (c) 2005,2006,2007 INRIA
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation;
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
*/
#ifndef PROPAGATION_LOSS_MODEL_H
#define PROPAGATION_LOSS_MODEL_H
#include "ns3/object.h"
#include "ns3/random-variable.h"
namespace ns3 {
class MobilityModel;
/**
* \brief Modelize the propagation loss through a transmission medium
*
* Calculate the receive power (dbm) from a transmit power (dbm),
* and, a mobility model for the source and destination positions.
*/
class PropagationLossModel : public Object
{
public:
static TypeId GetTypeId (void);
virtual ~PropagationLossModel ();
/**
* \param a the mobility model of the source
* \param b the mobility model of the destination
* \returns the attenuation coefficient (dB)
*/
virtual double GetLoss (Ptr<MobilityModel> a,
Ptr<MobilityModel> b) const = 0;
};
/**
* \brief The propagation loss is random
*/
class RandomPropagationLossModel : public PropagationLossModel
{
public:
static TypeId GetTypeId (void);
RandomPropagationLossModel ();
virtual ~RandomPropagationLossModel ();
virtual double GetLoss (Ptr<MobilityModel> a,
Ptr<MobilityModel> b) const;
private:
RandomVariable m_variable;
};
/**
* \brief a Friis propagation loss model
*
* The Friis propagation loss model was first described in
* "A Note on a Simple Transmission Formula", by
* "Harald T. Friis".
*
* The original equation was described as:
* \f$ \frac{P_r}{P_t} = \frac{A_r A_t}{d^2\lambda^2} \f$
* with the following equation for the case of an
* isotropic antenna with no heat loss:
* \f$ A_{isotr.} = \frac{\lambda^2}{4\pi} \f$
*
* The final equation becomes:
* \f$ \frac{P_r}{P_t} = \frac{\lambda^2}{(4 \pi d)^2} \f$
*
* Modern extensions to this original equation are:
* \f$ P_r = \frac{P_t G_t G_r \lambda^2}{(4 \pi d)^2 L}\f$
*
* With:
* - \f$ P_r \f$ : reception power (W)
* - \f$ P_t \f$ : transmission power (W)
* - \f$ G_t \f$ : transmission gain (unit-less)
* - \f$ G_r \f$ : reception gain (unit-less)
* - \f$ \lambda \f$ : wavelength (m)
* - \f$ d \f$ : distance (m)
* - \f$ L \f$ : system loss (unit-less)
*
*
* This model is invalid for small distance values.
* The current implementation returns the txpower as the rxpower
* for any distance smaller than MinDistance.
*/
class FriisPropagationLossModel : public PropagationLossModel
{
public:
static TypeId GetTypeId (void);
FriisPropagationLossModel ();
/**
* \param frequency (Hz)
* \param speed (m/s)
*
* Set the main wavelength used in the Friis model
* calculation.
*/
void SetLambda (double frequency, double speed);
/**
* \param lambda (m) the wavelength
*
* Set the main wavelength used in the Friis model
* calculation.
*/
void SetLambda (double lambda);
/**
* \param systemLoss (dimension-less)
*
* Set the system loss used by the Friis propagation model.
*/
void SetSystemLoss (double systemLoss);
/**
* \param minDistance the minimum distance
*
* Below this distance, the txpower is returned
* unmodified as the rxpower.
*/
void SetMinDistance (double minDistance);
/**
* \returns the current wavelength (m)
*/
double GetLambda (void) const;
/**
* \returns the current system loss (dimention-less)
*/
double GetSystemLoss (void) const;
virtual double GetLoss (Ptr<MobilityModel> a,
Ptr<MobilityModel> b) const;
private:
double DbmToW (double dbm) const;
double DbmFromW (double w) const;
static const double PI;
double m_lambda;
double m_systemLoss;
double m_minDistance;
};
/**
* \brief a log distance propagation model.
*
* This model calculates the reception power with a so-called
* log-distance propagation model:
* \f$ L = L_0 + 10 n log_{10}(\frac{d}{d_0})\f$
*
* where:
* - \f$ n \f$ : the path loss distance exponent
* - \f$ d_0 \f$ : reference distance (m)
* - \f$ L_0 \f$ : path loss at reference distance (dB)
* - \f$ d \f$ : distance (m)
* - \f$ L \f$ : path loss (dB)
*
* When the path loss is requested at a distance smaller than
* the reference distance, the tx power is returned.
*
*/
class LogDistancePropagationLossModel : public PropagationLossModel
{
public:
static TypeId GetTypeId (void);
LogDistancePropagationLossModel ();
/**
* \param n the path loss exponent.
* Set the path loss exponent.
*/
void SetPathLossExponent (double n);
/**
* \returns the current path loss exponent.
*/
double GetPathLossExponent (void) const;
/**
* \param model the reference propagation model
*/
void SetReferenceModel (Ptr<PropagationLossModel> model);
void SetReferenceDistance (double referenceDistance);
virtual double GetLoss (Ptr<MobilityModel> a,
Ptr<MobilityModel> b) const;
private:
static Ptr<PropagationLossModel> CreateDefaultReference (void);
double m_exponent;
double m_referenceDistance;
Ptr<PropagationLossModel> m_reference;
};
} // namespace ns3
#endif /* PROPAGATION_LOSS_MODEL_H */