fading.cpp

RFID reader 语 tag 模拟器

#include "fading.hpp"
#include "wireless_comm_signal.hpp"
#include "physical_layer.hpp"
#include "simulator.hpp"
#include "rand_num_generator.hpp"

const double Ricean::m_DEFAULT_MAX_VELOCITY = 6.5;
const double Ricean::m_DEFAULT_K = 6.0;
const t_uint Ricean::m_NUMBER_OF_POINTS = 16384;
const double Ricean::m_MAX_DOPPLER_FREQUENCY = 30.0;
const double Ricean::m_MAX_SAMPLE_RATE = 1000.0;

Fading::Fading()
{

}

Fading::Fading(const Fading& rhs)
{

}

Fading::~Fading()
{

}

Ricean::Ricean()
   : m_maxVelocity(m_DEFAULT_MAX_VELOCITY), m_kParameter(m_DEFAULT_K)
{

}

Ricean::Ricean(double maxVelocity, double k)
   : m_maxVelocity(maxVelocity), m_kParameter(k)
{

}

Ricean::Ricean(const Ricean& rhs)
   : m_maxVelocity(rhs.m_maxVelocity), m_kParameter(rhs.m_kParameter)
{

}

Rayleigh::Rayleigh()
   : Ricean(m_DEFAULT_MAX_VELOCITY, 0)
{

}

Rayleigh::Rayleigh(double maxVelocity)
   : Ricean(maxVelocity, 0)
{

}

Rayleigh::Rayleigh(const Rayleigh& rhs)
   : Ricean(rhs)
{

}

double Ricean::fadingFactor(const WirelessCommSignal& signal,
   const NodeId& nodeId)
{
   // This code is from the ns-2 module by Punnoose et al.
   // See their code and paper for details of the model.

   // MJM: I modified the model to compute a different fading
   // factor for each receiver to avoid having the same
   // fading factor globally for a given time instance.

   double maxFrequency = m_maxVelocity / signal.getWavelength();
   SimTime currentTime = Simulator::instance()->currentTime();
   double timeIndex = (currentTime.getTimeInSeconds() *
      m_MAX_SAMPLE_RATE * (maxFrequency / m_MAX_DOPPLER_FREQUENCY));
   timeIndex = timeIndex - (m_NUMBER_OF_POINTS *
      floor(timeIndex / m_NUMBER_OF_POINTS));

   // Envelope interpolation using Legendre polynomials
   int idx1 = static_cast<int>(floor(timeIndex));
   assert(idx1 >= 0 && idx1 < static_cast<int>(m_NUMBER_OF_POINTS));

   map<NodeId,int>::const_iterator p = m_nodeOffset.find(nodeId);
   if(p == m_nodeOffset.end()) {
      RandNumGeneratorPtr rand =
         Simulator::instance()->getRandNumGenerator();
      m_nodeOffset[nodeId] =
         rand->uniformInt(0, (m_NUMBER_OF_POINTS - 1));;
   }
   idx1 = (idx1 + m_nodeOffset[nodeId]) % m_NUMBER_OF_POINTS;

   int idx0 = (idx1 - 1 + m_NUMBER_OF_POINTS) % m_NUMBER_OF_POINTS;
   int idx2 = (idx1 + 1) % m_NUMBER_OF_POINTS;
   int idx3 = (idx1 + 2) % m_NUMBER_OF_POINTS;

   //double X1 = timeIndex - idx1;
   double X1 = timeIndex - floor(timeIndex);
   double X0 = X1 + 1.0;
   double X2 = X1 - 1.0;
   double X3 = X1 - 2.0;

   double interpolation1 =
      (m_GAUSSIAN_DATA1[idx0] * X1 * X2 * X3 / -6.0) +
      (m_GAUSSIAN_DATA1[idx1] * X0 * X2 * X3 * 0.5) +
      (m_GAUSSIAN_DATA1[idx2] * X0 * X1 * X3 * -0.5) +
      (m_GAUSSIAN_DATA1[idx3] * X0 * X1 * X2 / 6.0);

   double interpolation2 =
      (m_GAUSSIAN_DATA2[idx0] * X1 * X2 * X3 / -6.0) +
      (m_GAUSSIAN_DATA2[idx1] * X0 * X2 * X3 * 0.5) +
      (m_GAUSSIAN_DATA2[idx2] * X0 * X1 * X3 * -0.5) +
      (m_GAUSSIAN_DATA2[idx3] * X0 * X1 * X2 / 6.0);

   // The envelope multiplicative factor
   double numeratorTerm1 = interpolation1 + sqrt(2.0 * m_kParameter);
   double envelopeFactor =
      (pow(numeratorTerm1, 2) + pow(interpolation2, 2)) /
      (2.0 * (m_kParameter + 1));

   return envelopeFactor;
}

// These are generated values from the Punnoose et al.
// implementation.  I've hard-coded them rather than load
// from a file.
const double Ricean::m_GAUSSIAN_DATA1[m_NUMBER_OF_POINTS] =
{
-1.059166,
-1.230047,
-1.372025,
-1.485196,
-1.570531,
-1.629788,
-1.665405,
-1.680371,
-1.678082,
-1.662188,
-1.636435,
-1.604505,
-1.569873,
-1.535666,
-1.504541,
-1.478590,
-1.459267,
-1.447334,
-1.442852,
-1.445183,
-1.453035,
-1.464527,
-1.477274,
-1.488506,
-1.495187,
-1.494163,
-1.482299,
-1.456634,
-1.414520,
-1.353755,
-1.272704,
-1.170396,
-1.046604,
-0.901891,
-0.737635,
-0.556020,
-0.359999,
-0.153229,
0.060025,
0.275005,
0.486598,
0.689491,
0.878337,
1.047926,
1.193353,
1.310188,
1.394627,
1.443630,
1.455042,
1.427677,
1.361389,
1.257095,
1.116782,
0.943470,
0.741147,
0.514675,
0.269661,
0.012320,
-0.250705,
-0.512512,
-0.766141,
-1.004764,
-1.221875,
-1.411477,
-1.568253,
-1.687713,
-1.766322,
-1.801603,
-1.792207,
-1.737947,
-1.639808,
-1.499914,
-1.321473,
-1.108681,
-0.866610,
-0.601065,
-0.318423,
-0.025461,
0.270826,
0.563413,
0.845426,
1.110321,
1.352048,
1.565195,
1.745117,
1.888036,
1.991117,
2.052518,
2.071404,
2.047944,
1.983267,
1.879407,
1.739217,
1.566263,
1.364708,
1.139182,
0.894645,
0.636247,
0.369192,
0.098608,
-0.170577,
-0.433741,
-0.686662,
-0.925591,
-1.147308,
-1.349160,
-1.529074,
-1.685556,
-1.817671,
-1.925007,
-2.007627,
-2.066009,
-2.100982,
-2.113653,
-2.105338,
-2.077492,
-2.031647,
-1.969349,
-1.892118,
-1.801403,
-1.698561,
-1.584841,
-1.461382,
-1.329218,
-1.189303,
-1.042530,
-0.889764,
-0.731879,
-0.569794,
-0.404505,
-0.237118,
-0.068871,
0.098844,
0.264483,
0.426344,
0.582591,
0.731276,
0.870378,
0.997854,
1.111691,
1.209974,
1.290951,
1.353103,
1.395211,
1.416422,
1.416302,
1.394887,
1.352713,
1.290836,
1.210840,
1.114817,
1.005339,
0.885408,
0.758389,
0.627931,
0.497871,
0.372128,
0.254591,
0.149006,
0.058854,
-0.012756,
-0.063196,
-0.090411,
-0.092995,
-0.070257,
-0.022252,
0.050193,
0.145491,
0.261324,
0.394699,
0.542022,
0.699199,
0.861751,
1.024943,
1.183926,
1.333883,
1.470180,
1.588510,
1.685032,
1.756493,
1.800342,
1.814813,
1.798990,
1.752847,
1.677257,
1.573973,
1.445582,
1.295433,
1.127536,
0.946439,
0.757097,
0.564711,
0.374565,
0.191866,
0.021573,
-0.131762,
-0.264139,
-0.372239,
-0.453537,
-0.506382,
-0.530056,
-0.524799,
-0.491806,
-0.433187,
-0.351909,
-0.251693,
-0.136903,
-0.012400,
0.116612,
0.244760,
0.366672,
0.477159,
0.571383,
0.645020,
0.694405,
0.716655,
0.709765,
0.672686,
0.605356,
0.508711,
0.384662,
0.236032,
0.066473,
-0.119653,
-0.317409,
-0.521444,
-0.726162,
-0.925906,
-1.115138,
-1.288620,
-1.441581,
-1.569876,
-1.670115,
-1.739775,
-1.777283,
-1.782060,
-1.754542,
-1.696160,
-1.609292,
-1.497180,
-1.363819,
-1.213823,
-1.052267,
-0.884516,
-0.716044,
-0.552247,
-0.398263,
-0.258796,
-0.137958,
-0.039130,
0.035152,
0.083286,
0.104651,
0.099633,
0.069609,
0.016897,
-0.055324,
-0.143124,
-0.241961,
-0.346842,
-0.452495,
-0.553560,
-0.644775,
-0.721171,
-0.778249,
-0.812147,
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-0.748581,
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-0.559476,
-0.423737,
-0.264234,
-0.084918,
0.109447,
0.313427,
0.521087,
0.726180,
0.922347,
1.103319,
1.263128,
1.396300,
1.498042,
1.564407,
1.592430,
1.580239,
1.527129,
1.433602,
1.301363,
1.133286,
0.933338,
0.706467,
0.458460,
0.195777,
-0.074645,
-0.345599,
-0.609821,
-0.860216,
-1.090068,
-1.293247,
-1.464395,
-1.599091,
-1.693982,
-1.746885,
-1.756855,
-1.724206,
-1.650504,
-1.538512,
-1.392103,
-1.216136,
-1.016307,
-0.798965,
-0.570919,
-0.339224,
-0.110964,
0.106963,
0.308059,
0.486421,
0.636915,
0.755329,
0.838490,
0.884356,
0.892061,
0.861927,
0.795442,
0.695194,
0.564775,
0.408655,
0.232021,
0.040607,
-0.159502,
-0.362070,
-0.560912,
-0.750100,
-0.924141,
-1.078161,
-1.208046,
-1.310568,
-1.383477,
-1.425559,
-1.436656,
-1.417656,
-1.370442,
-1.297811,
-1.203364,
-1.091363,
-0.966576,
-0.834100,
-0.699174,
-0.566993,
-0.442519,
-0.330308,
-0.234347,
-0.157914,
-0.103464,
-0.072542,
-0.065733,
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-0.257531,
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-0.547148,
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-0.742418,
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-0.961470,
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-0.861589,
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-0.648667,
-0.501705,
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0.061025,
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0.488537,
0.700506,
0.902961,
1.089761,
1.255084,
1.393620,
1.500745,
1.572683,
1.606632,
1.600869,
1.554819,
1.469085,
1.345445,
1.186810,
0.997150,
0.781379,
0.545215,
0.295013,
0.037579,
-0.220038,
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-0.924256,
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0.089288,
0.195705,
0.280506,
0.342724,
0.382089,
0.399018,
0.394593,
0.370509,
0.329016,
0.272832,
0.205056,
0.129058,
0.048378,
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0.557531,
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0.794878,
0.845293,
0.878430,
0.893243,
0.889194,
0.866271,
0.824974,
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0.691680,
0.602981,
0.502397,
0.392397,
0.275651,
0.154948,
0.033107,
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1.894617,
2.034791,
2.140500,
2.209990,
2.242392,
2.237731,
2.196913,
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