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wifi: Rework calculations in NistErrorRateModel

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This commit is contained in:
Sebastien Deronne
2020-11-08 14:53:44 +01:00
committed by Sébastien Deronne
parent c2d2c81623
commit 7f0048ef78
2 changed files with 69 additions and 259 deletions
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222
src/wifi/model/nist-error-rate-model.cc
View File

@@ -19,9 +19,11 @@
* Sébastien Deronne <sebastien.deronne@gmail.com>
*/
#include <cmath>
#include <bitset>
#include "ns3/log.h"
#include "nist-error-rate-model.h"
#include "wifi-phy.h"
#include "wifi-tx-vector.h"
namespace ns3 {
@@ -65,50 +67,21 @@ NistErrorRateModel::GetQpskBer (double snr) const
}
double
NistErrorRateModel::Get16QamBer (double snr) const
NistErrorRateModel::GetQamBer (uint16_t constellationSize, double snr) const
{
NS_LOG_FUNCTION (this << snr);
double z = std::sqrt (snr / (5.0 * 2.0));
double ber = 0.75 * 0.5 * erfc (z);
NS_LOG_INFO ("16-Qam" << " snr=" << snr << " ber=" << ber);
NS_LOG_FUNCTION (this << constellationSize << snr);
NS_ASSERT (std::bitset<16> (constellationSize).count () == 1); //constellationSize has to be a power of 2
double z = std::sqrt (snr / ((2 * (constellationSize - 1)) / 3));
uint8_t bitsPerSymbol = std::sqrt (constellationSize);
double ber = ((bitsPerSymbol - 1) / (bitsPerSymbol * std::log2 (bitsPerSymbol))) * erfc (z);
NS_LOG_INFO (constellationSize << "-QAM: snr=" << snr << " ber=" << ber);
return ber;
}
double
NistErrorRateModel::Get64QamBer (double snr) const
NistErrorRateModel::GetFecBpskBer (double snr, uint64_t nbits, uint8_t bValue) const
{
NS_LOG_FUNCTION (this << snr);
double z = std::sqrt (snr / (21.0 * 2.0));
double ber = 7.0 / 12.0 * 0.5 * erfc (z);
NS_LOG_INFO ("64-Qam" << " snr=" << snr << " ber=" << ber);
return ber;
}
double
NistErrorRateModel::Get256QamBer (double snr) const
{
NS_LOG_FUNCTION (this << snr);
double z = std::sqrt (snr / (85.0 * 2.0));
double ber = 15.0 / 32.0 * 0.5 * erfc (z);
NS_LOG_INFO ("256-Qam" << " snr=" << snr << " ber=" << ber);
return ber;
}
double
NistErrorRateModel::Get1024QamBer (double snr) const
{
NS_LOG_FUNCTION (this << snr);
double z = std::sqrt (snr / (341.0 * 2.0));
double ber = 31.0 / 80.0 * 0.5 * erfc (z);
NS_LOG_INFO ("1024-Qam" << " snr=" << snr << " ber=" << ber);
return ber;
}
double
NistErrorRateModel::GetFecBpskBer (double snr, uint64_t nbits,
uint32_t bValue) const
{
NS_LOG_FUNCTION (this << snr << nbits << bValue);
NS_LOG_FUNCTION (this << snr << nbits << +bValue);
double ber = GetBpskBer (snr);
if (ber == 0.0)
{
@@ -121,10 +94,9 @@ NistErrorRateModel::GetFecBpskBer (double snr, uint64_t nbits,
}
double
NistErrorRateModel::GetFecQpskBer (double snr, uint64_t nbits,
uint32_t bValue) const
NistErrorRateModel::GetFecQpskBer (double snr, uint64_t nbits, uint8_t bValue) const
{
NS_LOG_FUNCTION (this << snr << nbits << bValue);
NS_LOG_FUNCTION (this << snr << nbits << +bValue);
double ber = GetQpskBer (snr);
if (ber == 0.0)
{
@@ -137,9 +109,9 @@ NistErrorRateModel::GetFecQpskBer (double snr, uint64_t nbits,
}
double
NistErrorRateModel::CalculatePe (double p, uint32_t bValue) const
NistErrorRateModel::CalculatePe (double p, uint8_t bValue) const
{
NS_LOG_FUNCTION (this << p << bValue);
NS_LOG_FUNCTION (this << p << +bValue);
double D = std::sqrt (4.0 * p * (1.0 - p));
double pe = 1.0;
if (bValue == 1)
@@ -209,11 +181,10 @@ NistErrorRateModel::CalculatePe (double p, uint32_t bValue) const
}
double
NistErrorRateModel::GetFec16QamBer (double snr, uint64_t nbits,
uint32_t bValue) const
NistErrorRateModel::GetFecQamBer (uint16_t constellationSize, double snr, uint64_t nbits, uint8_t bValue) const
{
NS_LOG_FUNCTION (this << snr << nbits << bValue);
double ber = Get16QamBer (snr);
NS_LOG_FUNCTION (this << constellationSize << snr << nbits << +bValue);
double ber = GetQamBer (constellationSize, snr);
if (ber == 0.0)
{
return 1.0;
@@ -224,52 +195,25 @@ NistErrorRateModel::GetFec16QamBer (double snr, uint64_t nbits,
return pms;
}
double
NistErrorRateModel::GetFec64QamBer (double snr, uint64_t nbits,
uint32_t bValue) const
uint8_t
NistErrorRateModel::GetBValue (WifiCodeRate codeRate) const
{
NS_LOG_FUNCTION (this << snr << nbits << bValue);
double ber = Get64QamBer (snr);
if (ber == 0.0)
switch (codeRate)
{
return 1.0;
case WIFI_CODE_RATE_3_4:
return 3;
case WIFI_CODE_RATE_2_3:
return 2;
case WIFI_CODE_RATE_1_2:
return 1;
case WIFI_CODE_RATE_5_6:
return 5;
case WIFI_CODE_RATE_UNDEFINED:
default:
NS_FATAL_ERROR ("Unknown code rate");
break;
}
double pe = CalculatePe (ber, bValue);
pe = std::min (pe, 1.0);
double pms = std::pow (1 - pe, nbits);
return pms;
}
double
NistErrorRateModel::GetFec256QamBer (double snr, uint64_t nbits,
uint32_t bValue) const
{
NS_LOG_FUNCTION (this << snr << nbits << bValue);
double ber = Get256QamBer (snr);
if (ber == 0.0)
{
return 1.0;
}
double pe = CalculatePe (ber, bValue);
pe = std::min (pe, 1.0);
double pms = std::pow (1 - pe, nbits);
return pms;
}
double
NistErrorRateModel::GetFec1024QamBer (double snr, uint64_t nbits,
uint32_t bValue) const
{
NS_LOG_FUNCTION (this << snr << nbits << bValue);
double ber = Get1024QamBer (snr);
if (ber == 0.0)
{
return 1.0;
}
double pe = CalculatePe (ber, bValue);
pe = std::min (pe, 1.0);
double pms = std::pow (1 - pe, nbits);
return pms;
return 0;
}
double
@@ -284,103 +228,15 @@ NistErrorRateModel::DoGetChunkSuccessRate (WifiMode mode, WifiTxVector txVector,
{
if (mode.GetConstellationSize () == 2)
{
if (mode.GetCodeRate () == WIFI_CODE_RATE_1_2)
{
return GetFecBpskBer (snr,
nbits,
1); //b value
}
else
{
return GetFecBpskBer (snr,
nbits,
3); //b value
}
return GetFecBpskBer (snr, nbits, GetBValue (mode.GetCodeRate ()));
}
else if (mode.GetConstellationSize () == 4)
{
if (mode.GetCodeRate () == WIFI_CODE_RATE_1_2)
{
return GetFecQpskBer (snr,
nbits,
1); //b value
}
else
{
return GetFecQpskBer (snr,
nbits,
3); //b value
}
return GetFecQpskBer (snr, nbits, GetBValue (mode.GetCodeRate ()));
}
else if (mode.GetConstellationSize () == 16)
else
{
if (mode.GetCodeRate () == WIFI_CODE_RATE_1_2)
{
return GetFec16QamBer (snr,
nbits,
1); //b value
}
else
{
return GetFec16QamBer (snr,
nbits,
3); //b value
}
}
else if (mode.GetConstellationSize () == 64)
{
if (mode.GetCodeRate () == WIFI_CODE_RATE_2_3)
{
return GetFec64QamBer (snr,
nbits,
2); //b value
}
else if (mode.GetCodeRate () == WIFI_CODE_RATE_5_6)
{
return GetFec64QamBer (snr,
nbits,
5); //b value
}
else
{
return GetFec64QamBer (snr,
nbits,
3); //b value
}
}
else if (mode.GetConstellationSize () == 256)
{
if (mode.GetCodeRate () == WIFI_CODE_RATE_5_6)
{
return GetFec256QamBer (snr,
nbits,
5 // b value
);
}
else
{
return GetFec256QamBer (snr,
nbits,
3 // b value
);
}
}
else if (mode.GetConstellationSize () == 1024)
{
if (mode.GetCodeRate () == WIFI_CODE_RATE_5_6)
{
return GetFec1024QamBer (snr,
nbits,
5 // b value
);
}
else
{
return GetFec1024QamBer (snr,
nbits,
3 // b value
);
}
return GetFecQamBer (mode.GetConstellationSize (), snr, nbits, GetBValue (mode.GetCodeRate ()));
}
}
return 0;

106
src/wifi/model/nist-error-rate-model.h
View File

@@ -22,6 +22,7 @@
#define NIST_ERROR_RATE_MODEL_H
#include "error-rate-model.h"
#include "wifi-mode.h"
namespace ns3 {
@@ -48,19 +49,27 @@ public:
private:
//Inherited from ErrorRateModel
double DoGetChunkSuccessRate (WifiMode mode, WifiTxVector txVector, double snr, uint64_t nbits) const;
/**
* Return the bValue such that coding rate = bValue / (bValue + 1).
*
* \param codeRate the coding rate
*
* \return the bValue such that coding rate = bValue / (bValue + 1)
*/
uint8_t GetBValue (WifiCodeRate codeRate) const;
/**
* Return the coded BER for the given p and b.
*
* \param p the SNR ratio (not dB)
* \param p the SNR ratio (in linear scale)
* \param bValue such that coding rate = bValue / (bValue + 1)
*
* \return the coded BER
*/
double CalculatePe (double p, uint32_t bValue) const;
double CalculatePe (double p, uint8_t bValue) const;
/**
* Return BER of BPSK at the given SNR.
*
* \param snr SNR ratio (not dB)
* \param snr SNR ratio (in linear scale)
*
* \return BER of BPSK at the given SNR
*/
@@ -68,105 +77,50 @@ private:
/**
* Return BER of QPSK at the given SNR.
*
* \param snr SNR ratio (not dB)
* \param snr SNR ratio (in linear scale)
*
* \return BER of QPSK at the given SNR
*/
double GetQpskBer (double snr) const;
/**
* Return BER of QAM16 at the given SNR.
* Return BER of QAM for a given constellation size at the given SNR.
*
* \param snr SNR ratio (not dB)
*
* \return BER of QAM16 at the given SNR
* \param constellationSize the constellation size (M)
* \param snr SNR ratio (in linear scale)
* \return BER of QAM for a given constellation size at the given SNR
*/
double Get16QamBer (double snr) const;
/**
* Return BER of QAM64 at the given SNR.
*
* \param snr SNR ratio (not dB)
*
* \return BER of QAM64 at the given SNR
*/
double Get64QamBer (double snr) const;
/**
* Return BER of QAM256 at the given SNR.
*
* \param snr SNR ratio (not dB)
* \return BER of QAM256 at the given SNR
*/
double Get256QamBer (double snr) const;
/**
* Return BER of QAM1024 at the given SNR.
*
* \param snr SNR ratio (not dB)
* \return BER of QAM1024 at the given SNR
*/
double Get1024QamBer (double snr) const;
double GetQamBer (uint16_t constellationSize, double snr) const;
/**
* Return BER of BPSK at the given SNR after applying FEC.
*
* \param snr SNR ratio (not dB)
* \param snr SNR ratio (in linear scale)
* \param nbits the number of bits in the chunk
* \param bValue such that coding rate = bValue / (bValue + 1)
* \param bValue the bValue such that coding rate = bValue / (bValue + 1)
*
* \return BER of BPSK at the given SNR after applying FEC
*/
double GetFecBpskBer (double snr, uint64_t nbits,
uint32_t bValue) const;
double GetFecBpskBer (double snr, uint64_t nbits, uint8_t bValue) const;
/**
* Return BER of QPSK at the given SNR after applying FEC.
*
* \param snr SNR ratio (not dB)
* \param snr SNR ratio (in linear scale)
* \param nbits the number of bits in the chunk
* \param bValue such that coding rate = bValue / (bValue + 1)
* \param bValue the bValue such that coding rate = bValue / (bValue + 1)
*
* \return BER of QPSK at the given SNR after applying FEC
*/
double GetFecQpskBer (double snr, uint64_t nbits,
uint32_t bValue) const;
double GetFecQpskBer (double snr, uint64_t nbits, uint8_t bValue) const;
/**
* Return BER of QAM16 at the given SNR after applying FEC.
* Return BER of QAM for a given constellation size at the given SNR after applying FEC.
*
* \param snr SNR ratio (not dB)
* \param constellationSize the constellation size (M)
* \param snr SNR ratio (in linear scale)
* \param nbits the number of bits in the chunk
* \param bValue such that coding rate = bValue / (bValue + 1)
* \param bValue the bValue such that coding rate = bValue / (bValue + 1)
*
* \return BER of QAM16 at the given SNR after applying FEC
* \return BER of QAM for a given constellation size at the given SNR after applying FEC
*/
double GetFec16QamBer (double snr, uint64_t nbits,
uint32_t bValue) const;
/**
* Return BER of QAM64 at the given SNR after applying FEC.
*
* \param snr SNR ratio (not dB)
* \param nbits the number of bits in the chunk
* \param bValue such that coding rate = bValue / (bValue + 1)
*
* \return BER of QAM64 at the given SNR after applying FEC
*/
double GetFec64QamBer (double snr, uint64_t nbits,
uint32_t bValue) const;
/**
* Return BER of QAM256 at the given SNR after applying FEC.
*
* \param snr SNR ratio (not dB)
* \param nbits the number of bits in the chunk
* \param bValue such that coding rate = bValue / (bValue + 1)
* \return BER of QAM256 at the given SNR after applying FEC
*/
double GetFec256QamBer (double snr, uint64_t nbits,
uint32_t bValue) const;
/**
* Return BER of QAM1024 at the given SNR after applying FEC.
*
* \param snr SNR ratio (not dB)
* \param nbits the number of bits in the chunk
* \param bValue such that coding rate = bValue / (bValue + 1)
* \return BER of QAM1024 at the given SNR after applying FEC
*/
double GetFec1024QamBer (double snr, uint64_t nbits,
uint32_t bValue) const;
double GetFecQamBer (uint16_t constellationSize, double snr, uint64_t nbits, uint8_t bValue) const;
};
} //namespace ns3