1 /* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */

     2 /*

     3  * Copyright (c) 2005,2006,2007 INRIA

     4  *

     5  * This program is free software; you can redistribute it and/or modify

     6  * it under the terms of the GNU General Public License version 2 as 

     7  * published by the Free Software Foundation;

     8  *

     9  * This program is distributed in the hope that it will be useful,

    10  * but WITHOUT ANY WARRANTY; without even the implied warranty of

    11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    12  * GNU General Public License for more details.

    13  *

    14  * You should have received a copy of the GNU General Public License

    15  * along with this program; if not, write to the Free Software

    16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    17  *

    18  * Author: Federico Maguolo <maguolof@dei.unipd.it>

    19  */

    20 

    21 #include "ns3/simulator.h"

    22 #include "ns3/uinteger.h"

    23 #include "ns3/double.h"

    24 #include "ns3/random-variable.h"

    25 #include "ns3/mobility-model.h"

    26 #include "ns3/log.h"

    27 #include "jakes-propagation-loss-model.h"

    28 #include <math.h>

    29 

    30 NS_LOG_COMPONENT_DEFINE ("Jakes");

    31 

    32 namespace ns3 {

    33 

    34 class JakesPropagationLossModel::PathCoefficients 

    35 {

    36 public:

    37   PathCoefficients (Ptr<const JakesPropagationLossModel> jakes,

    38                     Ptr<MobilityModel> receiver, 

    39                     uint8_t nRays, 

    40                     uint8_t nOscillators);

    41   ~PathCoefficients ();

    42   double GetLoss (void);

    43   Ptr<MobilityModel> GetReceiver (void);

    44 private:

    45   void DoConstruct (void);

    46   Ptr<MobilityModel> m_receiver;

    47   uint8_t m_nOscillators;

    48   uint8_t m_nRays;

    49   double **m_phases;

    50   Time m_lastUpdate;

    51   Ptr<const JakesPropagationLossModel> m_jakes;

    52 };

    53 

    54 

    55 JakesPropagationLossModel::PathCoefficients::PathCoefficients (Ptr<const JakesPropagationLossModel> jakes, 

    56                                                            Ptr<MobilityModel> receiver, 

    57                                                            uint8_t nRays, 

    58 							   uint8_t nOscillators)

    59   : m_receiver (receiver),

    60     m_nOscillators (nOscillators),

    61     m_nRays (nRays),

    62     m_jakes(jakes)

    63 {

    64   DoConstruct ();

    65 }

    66 

    67 JakesPropagationLossModel::PathCoefficients::~PathCoefficients ()

    68 {

    69   for (uint8_t i = 0; i < m_nRays; i++) 

    70     {

    71       delete [] m_phases[i];

    72     }

    73   delete [] m_phases;

    74 }

    75 

    76 void

    77 JakesPropagationLossModel::PathCoefficients::DoConstruct ()

    78 {

    79   m_phases = new double*[m_nRays];

    80   for (uint8_t i = 0; i < m_nRays; i++) 

    81     {

    82       m_phases[i] = new double[m_nOscillators + 1];

    83       for (uint8_t j = 0; j <= m_nOscillators; j++) 

    84         {

    85           m_phases[i][j] = 2.0 * JakesPropagationLossModel::PI * m_jakes->m_variable.GetValue ();

    86         }

    87     }

    88   m_lastUpdate = Simulator::Now ();

    89 }

    90 

    91 Ptr<MobilityModel>

    92 JakesPropagationLossModel::PathCoefficients::GetReceiver ()

    93 {

    94   return m_receiver;

    95 }

    96 

    97 double

    98 JakesPropagationLossModel::PathCoefficients::GetLoss (void)

    99 {

   100   uint16_t N = 4 * m_nOscillators + 2;

   101   Time interval = Simulator::Now () - m_lastUpdate;

   102   ComplexNumber coef= {0.0, 0.0};

   103   ComplexNumber fading;

   104   double norm = 0.0;

   105   for (uint8_t i = 0; i < m_nRays; i++) 

   106     {

   107       fading.real = 0.0;

   108       fading.imag = 0.0;

   109       for (uint8_t j = 0; j <= m_nOscillators; j++) 

   110         {

   111           m_phases[i][j] += 2.0 * JakesPropagationLossModel::PI * 

   112             cos (2.0 * JakesPropagationLossModel::PI * j / N) * m_jakes->m_fd * interval.GetSeconds ();

   113           m_phases[i][j] -= 2.0 * JakesPropagationLossModel::PI * 

   114             floor (m_phases[i][j] / 2.0 / JakesPropagationLossModel::PI);

   115           fading.real += m_jakes->m_amp[j].real * cos (m_phases[i][j]);

   116           fading.imag += m_jakes->m_amp[j].imag * cos (m_phases[i][j]);

   117           norm += sqrt(pow (m_jakes->m_amp[j].real, 2) + pow(m_jakes->m_amp[j].imag, 2));

   118         }

   119     coef.real += fading.real;

   120     coef.imag += fading.imag;

   121     }

   122   m_lastUpdate = Simulator::Now ();

   123   double k = sqrt (pow (coef.real, 2) + pow (coef.imag, 2)) / norm;

   124   NS_LOG_DEBUG ("Jakes coef "<< k << " (" << 10 * log10 (k) << "dB)");

   125   return 10 * log10 (k);

   126 }

   127 

   128 NS_OBJECT_ENSURE_REGISTERED (JakesPropagationLossModel);

   129 

   130 const double JakesPropagationLossModel::PI = 3.14159265358979323846;

   131 

   132 TypeId

   133 JakesPropagationLossModel::GetTypeId (void)

   134 {

   135   static TypeId tid = TypeId ("ns3::JakesPropagationLossModel")

   136     .SetParent<PropagationLossModel> ()

   137     .AddConstructor<JakesPropagationLossModel> ()

   138     .AddAttribute ("NumberOfRaysPerPath",

   139                    "The number of rays to use by default for compute the fading coeficent for a given path (default is 1)",

   140                    UintegerValue (1),

   141 		   MakeUintegerAccessor (&JakesPropagationLossModel::SetNRays,

   142                                          &JakesPropagationLossModel::GetNRays),

   143 		   MakeUintegerChecker<uint8_t> ())

   144     .AddAttribute ("NumberOfOscillatorsPerRay",

   145                    "The number of oscillators to use by default for compute the coeficent for a given ray of a given "

   146                    "path (default is 4)",

   147                    UintegerValue (4),

   148 		   MakeUintegerAccessor (&JakesPropagationLossModel::SetNOscillators,

   149                                          &JakesPropagationLossModel::GetNOscillators),

   150 		   MakeUintegerChecker<uint8_t> ())

   151     .AddAttribute ("DopplerFreq",

   152                    "The doppler frequency in Hz (f_d = v / lambda = v * f / c), the default is 0)",

   153                    DoubleValue (0.0),

   154 		   MakeDoubleAccessor (&JakesPropagationLossModel::m_fd),

   155 		   MakeDoubleChecker<double> ())

   156     .AddAttribute ("Distribution",

   157                    "The distribution to choose the initial phases.",

   158                    RandomVariableValue (ConstantVariable (1.0)),

   159                    MakeRandomVariableAccessor (&JakesPropagationLossModel::m_variable),

   160                    MakeRandomVariableChecker ())

   161     ;

   162   return tid;

   163 }

   164 

   165 JakesPropagationLossModel::JakesPropagationLossModel ()

   166   : m_amp (0),

   167     m_nRays (0),

   168     m_nOscillators (0)

   169 {}

   170 

   171 JakesPropagationLossModel::~JakesPropagationLossModel ()

   172 {

   173   delete [] m_amp;

   174   for (PathsList::iterator i = m_paths.end (); i != m_paths.begin (); i--) 

   175     {

   176       PathsSet *ps = *i;

   177       for (DestinationList::iterator r = ps->receivers.begin (); r != ps->receivers.end (); r++) 

   178         {

   179           PathCoefficients *pc = *r;

   180           delete pc;

   181         }

   182       delete ps;

   183     }

   184 }

   185 

   186 void

   187 JakesPropagationLossModel::SetNRays (uint8_t nRays)

   188 {

   189   m_nRays = nRays;

   190 }

   191 

   192 void

   193 JakesPropagationLossModel::SetNOscillators (uint8_t nOscillators)

   194 {

   195   m_nOscillators = nOscillators;

   196   delete [] m_amp;

   197   uint16_t N = 4 * m_nOscillators + 2;

   198   m_amp = new ComplexNumber[m_nOscillators + 1];

   199   m_amp[0].real = 2.0 * sqrt(2.0 / N) * cos (PI / 4.0);

   200   m_amp[0].imag = 2.0 * sqrt(2.0 / N) * sin (PI / 4.0);

   201   for (uint8_t i = 1; i <= m_nOscillators; i++) 

   202     {

   203       double beta = PI * (double)i / m_nOscillators;

   204       m_amp[i].real = 4.0 * cos (beta) / sqrt(N);

   205       m_amp[i].imag = 4.0 * sin (beta) / sqrt(N);

   206     }

   207 }

   208 

   209 uint8_t 

   210 JakesPropagationLossModel::GetNRays (void) const

   211 {

   212   return m_nRays;

   213 }

   214 uint8_t 

   215 JakesPropagationLossModel::GetNOscillators (void) const

   216 {

   217   return m_nOscillators;

   218 }

   219 

   220 

   221 double 

   222 JakesPropagationLossModel::DoCalcRxPower (double txPowerDbm,

   223                                           Ptr<MobilityModel> a,

   224                                           Ptr<MobilityModel> b) const

   225 {

   226   PathsList::iterator i = m_paths.end ();

   227   while (i != m_paths.begin ()) 

   228     {

   229       i--;

   230       PathsSet *ps = *i;

   231       if (ps->sender == a) 

   232         {

   233           m_paths.erase (i);

   234           m_paths.push_back (ps);

   235           for (DestinationList::iterator r = ps->receivers.begin (); r != ps->receivers.end (); r++) 

   236             {

   237               PathCoefficients *pc = *r;

   238               if (pc->GetReceiver () == b) 

   239                 {

   240                   ps->receivers.erase (r);

   241                   ps->receivers.push_back (pc);

   242                   return txPowerDbm + pc->GetLoss ();

   243                 }

   244             }

   245           PathCoefficients *pc = new PathCoefficients (this, b, m_nRays, m_nOscillators);

   246           ps->receivers.push_back (pc);

   247           return txPowerDbm + pc->GetLoss ();

   248         }

   249     }

   250   PathsSet *ps = new PathsSet;

   251   ps->sender = a;

   252   PathCoefficients *pc = new PathCoefficients (this, b, m_nRays, m_nOscillators);

   253   ps->receivers.push_back (pc);

   254   m_paths.push_back (ps);

   255   return txPowerDbm + pc->GetLoss ();

   256 }

   257 

   258 } // namespace ns3

   259