random-walk-2d-mobility-model.h

Go to the documentation of this file.

/*
 * Copyright (c) 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 RANDOM_WALK_2D_MOBILITY_MODEL_H
#define RANDOM_WALK_2D_MOBILITY_MODEL_H
 
#include "constant-velocity-helper.h"
#include "mobility-model.h"
#include "rectangle.h"
 
#include "ns3/event-id.h"
#include "ns3/nstime.h"
#include "ns3/object.h"
#include "ns3/random-variable-stream.h"
 
namespace ns3
{
 
/**
 * \ingroup mobility
 * \brief 2D random walk mobility model.
 *
 * Each instance moves with a speed and direction chosen at random
 * with the user-provided random variables until
 * either a fixed distance has been walked or until a fixed amount
 * of time. If we hit one of the boundaries (specified by a rectangle),
 * of the model, we rebound on the boundary with a reflexive angle
 * and speed. This model is often identified as a brownian motion
 * model.
 *
 * The Direction random variable is used for any point strictly
 * inside the boundaries. The points on the boundary have their
 * direction chosen randomly, without considering the Direction
 * Attribute.
 */
class RandomWalk2dMobilityModel : public MobilityModel
{
  public:
    /**
     * Register this type with the TypeId system.
     * \return the object TypeId
     */
    static TypeId GetTypeId();
 
    /** An enum representing the different working modes of this module. */
    enum Mode
    {
        MODE_DISTANCE,
        MODE_TIME
    };
 
  private:
    /**
     * \brief Performs the rebound of the node if it reaches a boundary
     * \param timeLeft The remaining time of the walk
     */
    void Rebound(Time timeLeft);
    /**
     * Walk according to position and velocity, until distance is reached,
     * time is reached, or intersection with the bounding box
     * \param timeLeft The remaining time of the walk
     */
    void DoWalk(Time timeLeft);
    /**
     * Perform initialization of the object before MobilityModel::DoInitialize ()
     */
    void DoInitializePrivate();
    void DoDispose() override;
    void DoInitialize() override;
    Vector DoGetPosition() const override;
    void DoSetPosition(const Vector& position) override;
    Vector DoGetVelocity() const override;
    int64_t DoAssignStreams(int64_t) override;
 
    ConstantVelocityHelper m_helper;       //!< helper for this object
    EventId m_event;                       //!< stored event ID
    Mode m_mode;                           //!< whether in time or distance mode
    double m_modeDistance;                 //!< Change direction and speed after this distance
    Time m_modeTime;                       //!< Change current direction and speed after this delay
    Ptr<RandomVariableStream> m_speed;     //!< rv for picking speed
    Ptr<RandomVariableStream> m_direction; //!< rv for picking direction
    Rectangle m_bounds;                    //!< Bounds of the area to cruise
};
 
} // namespace ns3
 
#endif /* RANDOM_WALK_2D_MOBILITY_MODEL_H */