A Discrete-Event Network Simulator
API
lr-wpan-spectrum-value-helper.cc
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1 /* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
2 /*
3  * Copyright (c) 2011 The Boeing Company
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
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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: Gary Pei <guangyu.pei@boeing.com>
19  */
21 #include <ns3/log.h>
22 #include <ns3/spectrum-value.h>
23 
24 #include <cmath>
25 
26 namespace ns3 {
27 
28 NS_LOG_COMPONENT_DEFINE ("LrWpanSpectrumValueHelper");
29 
31 
37 {
38 public:
40  {
41  NS_LOG_FUNCTION (this);
42 
43  Bands bands;
44  // 1 MHz resolution, with center frequency of 2400, 2401, ... 2483
45  // overall frequency span of 2399.5 MHz through 2483.5 MHz (83 bands)
46  for (int i = -1; i < 83; i++)
47  {
48  BandInfo bi;
49  bi.fl = 2400.5e6 + i * 1.0e6;
50  bi.fh = 2400.5e6 + (i + 1) * 1.0e6;
51  bi.fc = (bi.fl + bi.fh) / 2;
52  bands.push_back (bi);
53  }
54  g_LrWpanSpectrumModel = Create<SpectrumModel> (bands);
55  }
56 
58 
60 {
61  NS_LOG_FUNCTION (this);
62  m_noiseFactor = 1.0;
63 }
64 
66 {
67  NS_LOG_FUNCTION (this);
68 }
69 
72 {
73  NS_LOG_FUNCTION (this);
74  Ptr<SpectrumValue> txPsd = Create <SpectrumValue> (g_LrWpanSpectrumModel);
75 
76  // txPower is expressed in dBm. We must convert it into natural unit (W).
77  txPower = pow (10., (txPower - 30) / 10);
78 
79  // The effective occupied bandwidth of the signal is modelled to be 2 MHz.
80  // 99.5% of power is within +/- 1MHz of center frequency, and 0.5% is outside.
81  // There are 5 bands containing signal power. The middle (center) band
82  // contains half of the power. The two inner side bands contain 49.5%.
83  // The two outer side bands contain roughly 0.5%.
84  double txPowerDensity = txPower / 2.0e6;
85 
86  NS_ASSERT_MSG ((channel >= 11 && channel <= 26), "Invalid channel numbers");
87 
88  // The channel assignment is in section 6.1.2.1
89  // Channel 11 centered at 2.405 GHz, 12 at 2.410 GHz, ... 26 at 2.480 GHz
90  (*txPsd)[2405 + 5 * (channel - 11) - 2400 - 2] = txPowerDensity * 0.005;
91  (*txPsd)[2405 + 5 * (channel - 11) - 2400 - 1] = txPowerDensity * 0.495;
92  (*txPsd)[2405 + 5 * (channel - 11) - 2400] = txPowerDensity; // center
93  (*txPsd)[2405 + 5 * (channel - 11) - 2400 + 1 ] = txPowerDensity * 0.495;
94  (*txPsd)[2405 + 5 * (channel - 11) - 2400 + 2 ] = txPowerDensity * 0.005;
95 
96  // If more power is allocated to more subbands in future revisions of
97  // this model, make sure to renormalize so that the integral of the
98  // txPsd still equals txPower
99 
100  return txPsd;
101 }
102 
105 {
106  NS_LOG_FUNCTION (this);
107  Ptr<SpectrumValue> noisePsd = Create <SpectrumValue> (g_LrWpanSpectrumModel);
108 
109  static const double BOLTZMANN = 1.3803e-23;
110  // Nt is the power of thermal noise in W
111  double Nt = BOLTZMANN * 290.0;
112  // noise Floor (W) which accounts for thermal noise and non-idealities of the receiver
113  double noisePowerDensity = m_noiseFactor * Nt;
114 
115  NS_ASSERT_MSG ((channel >= 11 && channel <= 26), "Invalid channel numbers");
116 
117  (*noisePsd)[2405 + 5 * (channel - 11) - 2400 - 2] = noisePowerDensity;
118  (*noisePsd)[2405 + 5 * (channel - 11) - 2400 - 1] = noisePowerDensity;
119  (*noisePsd)[2405 + 5 * (channel - 11) - 2400] = noisePowerDensity;
120  (*noisePsd)[2405 + 5 * (channel - 11) - 2400 + 1] = noisePowerDensity;
121  (*noisePsd)[2405 + 5 * (channel - 11) - 2400 + 2] = noisePowerDensity;
122 
123  return noisePsd;
124 }
125 
126 double
128 {
129  NS_LOG_FUNCTION (psd);
130  double totalAvgPower = 0.0;
131 
132  NS_ASSERT (psd->GetSpectrumModel () == g_LrWpanSpectrumModel);
133 
134  // numerically integrate to get area under psd using 1 MHz resolution
135 
136  totalAvgPower += (*psd)[2405 + 5 * (channel - 11) - 2400 - 2];
137  totalAvgPower += (*psd)[2405 + 5 * (channel - 11) - 2400 - 1];
138  totalAvgPower += (*psd)[2405 + 5 * (channel - 11) - 2400];
139  totalAvgPower += (*psd)[2405 + 5 * (channel - 11) - 2400 + 1];
140  totalAvgPower += (*psd)[2405 + 5 * (channel - 11) - 2400 + 2];
141  totalAvgPower *= 1.0e6;
142 
143  return totalAvgPower;
144 }
145 
146 } // namespace ns3
Helper class used to automatically initialize the LrWpan Spectrum Model objects.
#define NS_LOG_FUNCTION(parameters)
If log level LOG_FUNCTION is enabled, this macro will output all input parameters separated by "...
NS_ASSERT_MSG(false, "Ipv4AddressGenerator::MaskToIndex(): Impossible")
#define NS_ASSERT(condition)
At runtime, in debugging builds, if this condition is not true, the program prints the source file...
Definition: assert.h:67
#define NS_LOG_COMPONENT_DEFINE(name)
Define a Log component with a specific name.
Definition: log.h:204
double m_noiseFactor
A scaling factor for the noise power.
std::vector< BandInfo > Bands
Container of BandInfo.
channel
Definition: third.py:92
Ptr< SpectrumModel > g_LrWpanSpectrumModel
Global object used to initialize the LrWpan Spectrum Model.
double fc
center frequency
Every class exported by the ns3 library is enclosed in the ns3 namespace.
double fl
lower limit of subband
Ptr< SpectrumValue > CreateNoisePowerSpectralDensity(uint32_t channel)
create spectrum value for noise
Ptr< SpectrumValue > CreateTxPowerSpectralDensity(double txPower, uint32_t channel)
create spectrum value
class ns3::LrWpanSpectrumModelInitializer g_LrWpanSpectrumModelInitializerInstance
Global object used to initialize the LrWpan Spectrum Model.
static double TotalAvgPower(Ptr< const SpectrumValue > psd, uint32_t channel)
total average power of the signal is the integral of the PSD using the limits of the given channel ...
double fh
upper limit of subband
The building block of a SpectrumModel.