A Discrete-Event Network Simulator
API
nist-error-rate-model.cc
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2010 The Boeing Company
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation;
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11  * GNU General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public License
14  * along with this program; if not, write to the Free Software
15  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
16  *
17  * Authors: Gary Pei <guangyu.pei@boeing.com>
18  * Sébastien Deronne <sebastien.deronne@gmail.com>
19  */
20 
21 #include "nist-error-rate-model.h"
22 
23 #include "wifi-tx-vector.h"
24 
25 #include "ns3/log.h"
26 
27 #include <bitset>
28 #include <cmath>
29 
30 namespace ns3
31 {
32 
33 NS_LOG_COMPONENT_DEFINE("NistErrorRateModel");
34 
35 NS_OBJECT_ENSURE_REGISTERED(NistErrorRateModel);
36 
37 TypeId
39 {
40  static TypeId tid = TypeId("ns3::NistErrorRateModel")
42  .SetGroupName("Wifi")
43  .AddConstructor<NistErrorRateModel>();
44  return tid;
45 }
46 
48 {
49 }
50 
51 double
53 {
54  NS_LOG_FUNCTION(this << snr);
55  double z = std::sqrt(snr);
56  double ber = 0.5 * erfc(z);
57  NS_LOG_INFO("bpsk snr=" << snr << " ber=" << ber);
58  return ber;
59 }
60 
61 double
63 {
64  NS_LOG_FUNCTION(this << snr);
65  double z = std::sqrt(snr / 2.0);
66  double ber = 0.5 * erfc(z);
67  NS_LOG_INFO("qpsk snr=" << snr << " ber=" << ber);
68  return ber;
69 }
70 
71 double
72 NistErrorRateModel::GetQamBer(uint16_t constellationSize, double snr) const
73 {
74  NS_LOG_FUNCTION(this << constellationSize << snr);
75  NS_ASSERT(std::bitset<16>(constellationSize).count() ==
76  1); // constellationSize has to be a power of 2
77  double z = std::sqrt(snr / ((2 * (constellationSize - 1)) / 3));
78  uint8_t bitsPerSymbol = std::sqrt(constellationSize);
79  double ber = ((bitsPerSymbol - 1) / (bitsPerSymbol * std::log2(bitsPerSymbol))) * erfc(z);
80  NS_LOG_INFO(constellationSize << "-QAM: snr=" << snr << " ber=" << ber);
81  return ber;
82 }
83 
84 double
85 NistErrorRateModel::GetFecBpskBer(double snr, uint64_t nbits, uint8_t bValue) const
86 {
87  NS_LOG_FUNCTION(this << snr << nbits << +bValue);
88  double ber = GetBpskBer(snr);
89  if (ber == 0.0)
90  {
91  return 1.0;
92  }
93  double pe = CalculatePe(ber, bValue);
94  pe = std::min(pe, 1.0);
95  double pms = std::pow(1 - pe, nbits);
96  return pms;
97 }
98 
99 double
100 NistErrorRateModel::GetFecQpskBer(double snr, uint64_t nbits, uint8_t bValue) const
101 {
102  NS_LOG_FUNCTION(this << snr << nbits << +bValue);
103  double ber = GetQpskBer(snr);
104  if (ber == 0.0)
105  {
106  return 1.0;
107  }
108  double pe = CalculatePe(ber, bValue);
109  pe = std::min(pe, 1.0);
110  double pms = std::pow(1 - pe, nbits);
111  return pms;
112 }
113 
114 double
115 NistErrorRateModel::CalculatePe(double p, uint8_t bValue) const
116 {
117  NS_LOG_FUNCTION(this << p << +bValue);
118  double D = std::sqrt(4.0 * p * (1.0 - p));
119  double pe = 1.0;
120  if (bValue == 1)
121  {
122  // code rate 1/2, use table 3.1.1
123  pe = 0.5 * (36.0 * std::pow(D, 10) + 211.0 * std::pow(D, 12) + 1404.0 * std::pow(D, 14) +
124  11633.0 * std::pow(D, 16) + 77433.0 * std::pow(D, 18) +
125  502690.0 * std::pow(D, 20) + 3322763.0 * std::pow(D, 22) +
126  21292910.0 * std::pow(D, 24) + 134365911.0 * std::pow(D, 26));
127  }
128  else if (bValue == 2)
129  {
130  // code rate 2/3, use table 3.1.2
131  pe = 1.0 / (2.0 * bValue) *
132  (3.0 * std::pow(D, 6) + 70.0 * std::pow(D, 7) + 285.0 * std::pow(D, 8) +
133  1276.0 * std::pow(D, 9) + 6160.0 * std::pow(D, 10) + 27128.0 * std::pow(D, 11) +
134  117019.0 * std::pow(D, 12) + 498860.0 * std::pow(D, 13) +
135  2103891.0 * std::pow(D, 14) + 8784123.0 * std::pow(D, 15));
136  }
137  else if (bValue == 3)
138  {
139  // code rate 3/4, use table 3.1.2
140  pe = 1.0 / (2.0 * bValue) *
141  (42.0 * std::pow(D, 5) + 201.0 * std::pow(D, 6) + 1492.0 * std::pow(D, 7) +
142  10469.0 * std::pow(D, 8) + 62935.0 * std::pow(D, 9) + 379644.0 * std::pow(D, 10) +
143  2253373.0 * std::pow(D, 11) + 13073811.0 * std::pow(D, 12) +
144  75152755.0 * std::pow(D, 13) + 428005675.0 * std::pow(D, 14));
145  }
146  else if (bValue == 5)
147  {
148  // code rate 5/6, use table V from D. Haccoun and G. Begin, "High-Rate Punctured
149  // Convolutional Codes for Viterbi Sequential Decoding", IEEE Transactions on
150  // Communications, Vol. 32, Issue 3, pp.315-319.
151  pe = 1.0 / (2.0 * bValue) *
152  (92.0 * std::pow(D, 4.0) + 528.0 * std::pow(D, 5.0) + 8694.0 * std::pow(D, 6.0) +
153  79453.0 * std::pow(D, 7.0) + 792114.0 * std::pow(D, 8.0) +
154  7375573.0 * std::pow(D, 9.0) + 67884974.0 * std::pow(D, 10.0) +
155  610875423.0 * std::pow(D, 11.0) + 5427275376.0 * std::pow(D, 12.0) +
156  47664215639.0 * std::pow(D, 13.0));
157  }
158  else
159  {
160  NS_ASSERT(false);
161  }
162  return pe;
163 }
164 
165 double
166 NistErrorRateModel::GetFecQamBer(uint16_t constellationSize,
167  double snr,
168  uint64_t nbits,
169  uint8_t bValue) const
170 {
171  NS_LOG_FUNCTION(this << constellationSize << snr << nbits << +bValue);
172  double ber = GetQamBer(constellationSize, snr);
173  if (ber == 0.0)
174  {
175  return 1.0;
176  }
177  double pe = CalculatePe(ber, bValue);
178  pe = std::min(pe, 1.0);
179  double pms = std::pow(1 - pe, nbits);
180  return pms;
181 }
182 
183 uint8_t
185 {
186  switch (codeRate)
187  {
188  case WIFI_CODE_RATE_3_4:
189  return 3;
190  case WIFI_CODE_RATE_2_3:
191  return 2;
192  case WIFI_CODE_RATE_1_2:
193  return 1;
194  case WIFI_CODE_RATE_5_6:
195  return 5;
197  default:
198  NS_FATAL_ERROR("Unknown code rate");
199  break;
200  }
201  return 0;
202 }
203 
204 double
206  const WifiTxVector& txVector,
207  double snr,
208  uint64_t nbits,
209  uint8_t numRxAntennas,
210  WifiPpduField field,
211  uint16_t staId) const
212 {
213  NS_LOG_FUNCTION(this << mode << snr << nbits << +numRxAntennas << field << staId);
215  {
216  if (mode.GetConstellationSize() == 2)
217  {
218  return GetFecBpskBer(snr, nbits, GetBValue(mode.GetCodeRate()));
219  }
220  else if (mode.GetConstellationSize() == 4)
221  {
222  return GetFecQpskBer(snr, nbits, GetBValue(mode.GetCodeRate()));
223  }
224  else
225  {
226  return GetFecQamBer(mode.GetConstellationSize(),
227  snr,
228  nbits,
229  GetBValue(mode.GetCodeRate()));
230  }
231  }
232  return 0;
233 }
234 
235 } // namespace ns3
#define min(a, b)
Definition: 80211b.c:41
the interface for Wifi's error models
A model for the error rate for different modulations.
static TypeId GetTypeId()
Get the type ID.
double GetQamBer(uint16_t constellationSize, double snr) const
Return BER of QAM for a given constellation size at the given SNR.
double GetBpskBer(double snr) const
Return BER of BPSK at the given SNR.
double GetFecBpskBer(double snr, uint64_t nbits, uint8_t bValue) const
Return BER of BPSK at the given SNR after applying FEC.
double CalculatePe(double p, uint8_t bValue) const
Return the coded BER for the given p and b.
double GetFecQpskBer(double snr, uint64_t nbits, uint8_t bValue) const
Return BER of QPSK at the given SNR after applying FEC.
double GetFecQamBer(uint16_t constellationSize, double snr, uint64_t nbits, uint8_t bValue) const
Return BER of QAM for a given constellation size at the given SNR after applying FEC.
uint8_t GetBValue(WifiCodeRate codeRate) const
Return the bValue such that coding rate = bValue / (bValue + 1).
double DoGetChunkSuccessRate(WifiMode mode, const WifiTxVector &txVector, double snr, uint64_t nbits, uint8_t numRxAntennas, WifiPpduField field, uint16_t staId) const override
A pure virtual method that must be implemented in the subclass.
double GetQpskBer(double snr) const
Return BER of QPSK at the given SNR.
a unique identifier for an interface.
Definition: type-id.h:59
TypeId SetParent(TypeId tid)
Set the parent TypeId.
Definition: type-id.cc:931
represent a single transmission mode
Definition: wifi-mode.h:51
uint16_t GetConstellationSize() const
Definition: wifi-mode.cc:141
WifiModulationClass GetModulationClass() const
Definition: wifi-mode.cc:185
WifiCodeRate GetCodeRate() const
Definition: wifi-mode.cc:134
This class mimics the TXVECTOR which is to be passed to the PHY in order to define the parameters whi...
#define NS_ASSERT(condition)
At runtime, in debugging builds, if this condition is not true, the program prints the source file,...
Definition: assert.h:66
#define NS_FATAL_ERROR(msg)
Report a fatal error with a message and terminate.
Definition: fatal-error.h:179
#define NS_LOG_COMPONENT_DEFINE(name)
Define a Log component with a specific name.
Definition: log.h:202
#define NS_LOG_FUNCTION(parameters)
If log level LOG_FUNCTION is enabled, this macro will output all input parameters separated by ",...
#define NS_LOG_INFO(msg)
Use NS_LOG to output a message of level LOG_INFO.
Definition: log.h:275
#define NS_OBJECT_ENSURE_REGISTERED(type)
Register an Object subclass with the TypeId system.
Definition: object-base.h:46
WifiPpduField
The type of PPDU field (grouped for convenience)
@ WIFI_MOD_CLASS_ERP_OFDM
ERP-OFDM (18.4)
Every class exported by the ns3 library is enclosed in the ns3 namespace.
WifiCodeRate
These constants define the various convolutional coding rates used for the OFDM transmission modes in...
@ WIFI_CODE_RATE_2_3
2/3 coding rate
@ WIFI_CODE_RATE_1_2
1/2 coding rate
@ WIFI_CODE_RATE_3_4
3/4 coding rate
@ WIFI_CODE_RATE_UNDEFINED
undefined coding rate
@ WIFI_CODE_RATE_5_6
5/6 coding rate