A Discrete-Event Network Simulator
API
dsss-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 * Author: Gary Pei <guangyu.pei@boeing.com>
18 */
19
21
22#include "ns3/log.h"
23
24#include <cmath>
25
26namespace ns3
27{
28
29NS_LOG_COMPONENT_DEFINE("DsssErrorRateModel");
30
31#ifndef HAVE_GSL
32const double DsssErrorRateModel::WLAN_SIR_PERFECT = 10.0;
34#endif
35
36double
38{
40 return ((std::sqrt(2.0) + 1.0) / std::sqrt(8.0 * M_PI * std::sqrt(2.0))) *
41 (1.0 / std::sqrt(x)) * std::exp(-(2.0 - std::sqrt(2.0)) * x);
42}
43
44double
46{
48 double EbN0 = sinr * 22000000.0 / 1000000.0; // 1 bit per symbol with 1 MSPS
49 double ber = 0.5 * std::exp(-EbN0);
50 return std::pow((1.0 - ber), static_cast<double>(nbits));
51}
52
53double
55{
57 double EbN0 = sinr * 22000000.0 / 1000000.0 / 2.0; // 2 bits per symbol, 1 MSPS
58 double ber = DqpskFunction(EbN0);
59 return std::pow((1.0 - ber), static_cast<double>(nbits));
60}
61
62double
64{
66#ifdef HAVE_GSL
67 // symbol error probability
68 double EbN0 = sinr * 22000000.0 / 1375000.0 / 4.0;
69 double sep = SymbolErrorProb16Cck(4.0 * EbN0 / 2.0);
70 return std::min(1.0, std::pow(1.0 - sep, nbits / 4.0));
71#else
72 NS_LOG_WARN("Running a 802.11b CCK Matlab model less accurate than GSL model");
73 // The Matlab model
74 double ber;
75 if (sinr > WLAN_SIR_PERFECT)
76 {
77 ber = 0.0;
78 }
79 else if (sinr < WLAN_SIR_IMPOSSIBLE)
80 {
81 ber = 0.5;
82 }
83 else
84 {
85 // fitprops.coeff from Matlab berfit
86 double a1 = 5.3681634344056195e-001;
87 double a2 = 3.3092430025608586e-003;
88 double a3 = 4.1654372361004000e-001;
89 double a4 = 1.0288981434358866e+000;
90 ber = a1 * std::exp(-std::pow((sinr - a2) / a3, a4));
91 }
92 return std::min(1.0, std::pow((1.0 - ber), static_cast<double>(nbits)));
93#endif
94}
95
96double
98{
100#ifdef HAVE_GSL
101 NS_LOG_DEBUG("GSL enabled ");
102 // symbol error probability
103 double EbN0 = sinr * 22000000.0 / 1375000.0 / 8.0;
104 double sep = SymbolErrorProb256Cck(8.0 * EbN0 / 2.0);
105 return std::min(1.0, std::pow(1.0 - sep, nbits / 8.0));
106#else
107 NS_LOG_WARN("Running a 802.11b CCK Matlab model less accurate than GSL model");
108 // The Matlab model
109 double ber;
110 if (sinr > WLAN_SIR_PERFECT)
111 {
112 ber = 0.0;
113 }
114 else if (sinr < WLAN_SIR_IMPOSSIBLE)
115 {
116 ber = 0.5;
117 }
118 else
119 {
120 // fitprops.coeff from Matlab berfit
121 double a1 = 7.9056742265333456e-003;
122 double a2 = -1.8397449399176360e-001;
123 double a3 = 1.0740689468707241e+000;
124 double a4 = 1.0523316904502553e+000;
125 double a5 = 3.0552298746496687e-001;
126 double a6 = 2.2032715128698435e+000;
127 ber = (a1 * sinr * sinr + a2 * sinr + a3) /
128 (sinr * sinr * sinr + a4 * sinr * sinr + a5 * sinr + a6);
129 }
130 return std::min(1.0, std::pow((1.0 - ber), static_cast<double>(nbits)));
131#endif
132}
133
134#ifdef HAVE_GSL
135double
136IntegralFunction(double x, void* params)
137{
138 double beta = ((FunctionParameters*)params)->beta;
139 double n = ((FunctionParameters*)params)->n;
140 double IntegralFunction = std::pow(2 * gsl_cdf_ugaussian_P(x + beta) - 1, n - 1) *
141 std::exp(-x * x / 2.0) / std::sqrt(2.0 * M_PI);
142 return IntegralFunction;
143}
144
145double
146DsssErrorRateModel::SymbolErrorProb16Cck(double e2)
147{
148 double sep;
149 double error;
150
151 FunctionParameters params;
152 params.beta = std::sqrt(2.0 * e2);
153 params.n = 8.0;
154
155 gsl_integration_workspace* w = gsl_integration_workspace_alloc(1000);
156
157 gsl_function F;
158 F.function = &IntegralFunction;
159 F.params = &params;
160
161 gsl_integration_qagiu(&F, -params.beta, 0, 1e-7, 1000, w, &sep, &error);
162 gsl_integration_workspace_free(w);
163 if (error == 0.0)
164 {
165 sep = 1.0;
166 }
167
168 return 1.0 - sep;
169}
170
171double
172DsssErrorRateModel::SymbolErrorProb256Cck(double e1)
173{
174 return 1.0 - std::pow(1.0 - SymbolErrorProb16Cck(e1 / 2.0), 2.0);
175}
176
177#endif
178
179} // namespace ns3
#define min(a, b)
Definition: 80211b.c:42
static double GetDsssDqpskSuccessRate(double sinr, uint64_t nbits)
Return the chunk success rate of the differential encoded QPSK.
static const double WLAN_SIR_PERFECT
WLAN perfect.
static double GetDsssDbpskSuccessRate(double sinr, uint64_t nbits)
Return the chunk success rate of the differential BPSK.
static double GetDsssDqpskCck5_5SuccessRate(double sinr, uint64_t nbits)
Return the chunk success rate of the differential encoded QPSK for 5.5Mbps data rate.
static double GetDsssDqpskCck11SuccessRate(double sinr, uint64_t nbits)
Return the chunk success rate of the differential encoded QPSK for 11Mbps data rate.
static const double WLAN_SIR_IMPOSSIBLE
WLAN impossible.
static double DqpskFunction(double x)
A function DQPSK.
#define NS_LOG_COMPONENT_DEFINE(name)
Define a Log component with a specific name.
Definition: log.h:202
#define NS_LOG_DEBUG(msg)
Use NS_LOG to output a message of level LOG_DEBUG.
Definition: log.h:268
#define NS_LOG_FUNCTION_NOARGS()
Output the name of the function.
#define NS_LOG_WARN(msg)
Use NS_LOG to output a message of level LOG_WARN.
Definition: log.h:261
Every class exported by the ns3 library is enclosed in the ns3 namespace.