src/devices/wifi/jakes-propagation-loss-model.cc
changeset 2678 22aa62a108ed
child 2681 9a13f9faf4a5
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/devices/wifi/jakes-propagation-loss-model.cc	Fri Mar 21 04:51:36 2008 +0100
@@ -0,0 +1,235 @@
+/* -*-  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: Federico Maguolo <maguolof@dei.unipd.it>
+ */
+
+#include "ns3/simulator.h"
+#include "ns3/uinteger.h"
+#include "ns3/double.h"
+#include "ns3/random-variable.h"
+#include "ns3/default-value.h"
+#include "ns3/mobility-model.h"
+#include "ns3/log.h"
+#include "jakes-propagation-loss-model.h"
+#include <math.h>
+
+NS_LOG_COMPONENT_DEFINE ("Jakes");
+
+namespace ns3 {
+
+
+
+class JakesPropagationLossModel::PathCoefficients {
+public:
+  PathCoefficients (Ptr<const JakesPropagationLossModel> jakes,
+                    Ptr<MobilityModel> receiver, 
+                    uint8_t nRays, 
+                    uint8_t nOscillators);
+  ~PathCoefficients ();
+  double GetLoss (void);
+  Ptr<MobilityModel> GetReceiver (void);
+private:
+  void DoConstruct (void);
+  Ptr<MobilityModel> m_receiver;
+  uint8_t m_nOscillators;
+  uint8_t m_nRays;
+  double **m_phases;
+  Time m_lastUpdate;
+  Ptr<const JakesPropagationLossModel> m_jakes;
+};
+
+
+JakesPropagationLossModel::PathCoefficients::PathCoefficients (Ptr<const JakesPropagationLossModel> jakes, 
+                                                           Ptr<MobilityModel> receiver, 
+                                                           uint8_t nRays, 
+							   uint8_t nOscillators)
+  : m_receiver (receiver),
+    m_nOscillators (nOscillators),
+    m_nRays (nRays),
+    m_jakes(jakes)
+{
+  DoConstruct ();
+}
+
+JakesPropagationLossModel::PathCoefficients::~PathCoefficients ()
+{
+  for (uint8_t i = 0; i < m_nRays; i++) {
+    delete [] m_phases[i];
+  }
+  delete [] m_phases;
+}
+
+void
+JakesPropagationLossModel::PathCoefficients::DoConstruct ()
+{
+  m_phases = new double*[m_nRays];
+  for (uint8_t i = 0; i < m_nRays; i++) {
+    m_phases[i] = new double[m_nOscillators + 1];
+    for (uint8_t j = 0; j <= m_nOscillators; j++) {
+      m_phases[i][j] = 2.0 * JakesPropagationLossModel::PI * m_jakes->m_variable.GetValue ();
+    }
+  }
+  m_lastUpdate = Simulator::Now ();
+}
+
+Ptr<MobilityModel>
+JakesPropagationLossModel::PathCoefficients::GetReceiver ()
+{
+  return m_receiver;
+}
+
+double
+JakesPropagationLossModel::PathCoefficients::GetLoss (void)
+{
+  uint16_t N = 4 * m_nOscillators + 2;
+  Time interval = Simulator::Now () - m_lastUpdate;
+  ComplexNumber coef= {0.0, 0.0};
+  ComplexNumber fading;
+  double norm = 0.0;
+  for (uint8_t i = 0; i < m_nRays; i++) {
+    fading.real = 0.0;
+    fading.imag = 0.0;
+    for (uint8_t j = 0; j <= m_nOscillators; j++) {
+      m_phases[i][j] += 2.0 * JakesPropagationLossModel::PI * cos (2.0 * JakesPropagationLossModel::PI * j / N) * m_jakes->m_fd * interval.GetSeconds ();
+      m_phases[i][j] -= 2.0 * JakesPropagationLossModel::PI * floor (m_phases[i][j] / 2.0 / JakesPropagationLossModel::PI);
+      fading.real += m_jakes->m_amp[j].real * cos (m_phases[i][j]);
+      fading.imag += m_jakes->m_amp[j].imag * cos (m_phases[i][j]);
+      norm += sqrt(pow (m_jakes->m_amp[j].real, 2) + pow(m_jakes->m_amp[j].imag, 2));
+    }
+    coef.real += fading.real;
+    coef.imag += fading.imag;
+  }
+  m_lastUpdate = Simulator::Now ();
+  double k = sqrt (pow (coef.real, 2) + pow (coef.imag, 2)) / norm;
+  NS_LOG_DEBUG ("Jakes coef "<< k << " (" << 10 * log10 (k) << "dB)");
+  return 10 * log10 (k);
+}
+
+NS_OBJECT_ENSURE_REGISTERED (JakesPropagationLossModel);
+
+const double JakesPropagationLossModel::PI = 3.1415;
+
+TypeId
+JakesPropagationLossModel::GetTypeId (void)
+{
+  static TypeId tid = TypeId ("ns3::JakesPropagationLossModel")
+    .SetParent<PropagationLossModel> ()
+    .AddConstructor<JakesPropagationLossModel> ()
+    .AddAttribute ("NumberOfRaysPerPath",
+                   "The number of rays to use by default for compute the fading coeficent for a given path (default is 1)",
+                   Uinteger (1),
+		   MakeUintegerAccessor (&JakesPropagationLossModel::m_nRays),
+		   MakeUintegerChecker<uint8_t> ())
+    .AddAttribute ("NumberOfOscillatorsPerRay",
+                   "The number of oscillators to use by default for compute the coeficent for a given ray of a given path (default is 4)",
+                   Uinteger (4),
+		   MakeUintegerAccessor (&JakesPropagationLossModel::m_nOscillators),
+		   MakeUintegerChecker<uint8_t> ())
+    .AddAttribute ("DopplerFreq",
+                   "The doppler frequency in Hz (f_d = v / lambda = v * f / c, the defualt is 0)",
+                   Double(0.0),
+		   MakeDoubleAccessor (&JakesPropagationLossModel::m_fd),
+		   MakeDoubleChecker<double> ())
+    .AddAttribute ("Distribution",
+                   "The distribution to choose the initial phases.",
+                   ConstantVariable (1.0),
+                   MakeRandomVariableAccessor (&JakesPropagationLossModel::m_variable),
+                   MakeRandomVariableChecker ())
+    ;
+  return tid;
+}
+
+JakesPropagationLossModel::JakesPropagationLossModel ()
+{
+  DoConstruct ();
+}
+
+JakesPropagationLossModel::~JakesPropagationLossModel ()
+{
+  delete [] m_amp;
+  for (PathsList::iterator i = m_paths.end (); i != m_paths.begin (); i--) {
+    PathsSet *ps = *i;
+    for (DestinationList::iterator r = ps->receivers.begin (); r != ps->receivers.end (); r++) {
+      PathCoefficients *pc = *r;
+      delete pc;
+    }
+    delete ps;
+  }
+}
+
+void
+JakesPropagationLossModel::DoConstruct ()
+{
+  uint16_t N = 4 * m_nOscillators + 2;
+  m_amp = new ComplexNumber[m_nOscillators + 1];
+  m_amp[0].real = 2.0 * sqrt(2.0 / N) * cos (PI / 4.0);
+  m_amp[0].imag = 2.0 * sqrt(2.0 / N) * sin (PI / 4.0);
+  for (uint8_t i = 1; i <= m_nOscillators; i++) {
+    double beta = PI * (double)i / m_nOscillators;
+    m_amp[i].real = 4.0 * cos (beta) / sqrt(N);
+    m_amp[i].imag = 4.0 * sin (beta) / sqrt(N);
+  }
+}
+
+void
+JakesPropagationLossModel::SetNRays (uint8_t nRays)
+{
+  m_nRays = nRays;
+}
+
+void
+JakesPropagationLossModel::SetNOscillators (uint8_t nOscillators)
+{
+  m_nOscillators = nOscillators;
+}
+
+double
+JakesPropagationLossModel::GetLoss (Ptr<MobilityModel> a,
+				    Ptr<MobilityModel> b) const
+{
+  PathsList::iterator i = m_paths.end ();
+  while (i != m_paths.begin ()) {
+    i--;
+    PathsSet *ps = *i;
+    if (PeekPointer (ps->sender) == PeekPointer(a)) {
+      m_paths.erase (i);
+      m_paths.push_back (ps);
+      for (DestinationList::iterator r = ps->receivers.begin (); r != ps->receivers.end (); r++) {
+        PathCoefficients *pc = *r;
+      	if (PeekPointer (pc->GetReceiver ()) == PeekPointer (b)) {
+          ps->receivers.erase (r);
+	  ps->receivers.push_back (pc);
+	  return pc->GetLoss ();
+	}
+      }
+      PathCoefficients *pc = new PathCoefficients (this, b, m_nRays, m_nOscillators);
+      ps->receivers.push_back (pc);
+      return pc->GetLoss ();
+    }
+  }
+  PathsSet *ps = new PathsSet;
+  ps->sender = a;
+  PathCoefficients *pc = new PathCoefficients (this, b, m_nRays, m_nOscillators);
+  ps->receivers.push_back (pc);
+  m_paths.push_back (ps);
+  return pc->GetLoss ();
+}
+
+
+} // namespace ns3
+