/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
* Copyright (c) 2005,2006 INRIA
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation;
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Authors: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
* Sébastien Deronne <sebastien.deronne@gmail.com>
*/
#include "ns3/packet.h"
#include "ns3/simulator.h"
#include "ns3/log.h"
#include "interference-helper.h"
#include "wifi-phy.h"
#include "error-rate-model.h"
namespace ns3 {
NS_LOG_COMPONENT_DEFINE ("InterferenceHelper");
/****************************************************************
* Phy event class
****************************************************************/
Event::Event (Ptr<const Packet> packet, WifiTxVector txVector, Time duration, double rxPower)
: m_packet (packet),
m_txVector (txVector),
m_startTime (Simulator::Now ()),
m_endTime (m_startTime + duration),
m_rxPowerW (rxPower)
{
}
Event::~Event ()
{
}
Ptr<const Packet>
Event::GetPacket (void) const
{
return m_packet;
}
Time
Event::GetStartTime (void) const
{
return m_startTime;
}
Time
Event::GetEndTime (void) const
{
return m_endTime;
}
double
Event::GetRxPowerW (void) const
{
return m_rxPowerW;
}
WifiTxVector
Event::GetTxVector (void) const
{
return m_txVector;
}
WifiMode
Event::GetPayloadMode (void) const
{
return m_txVector.GetMode ();
}
/****************************************************************
* Class which records SNIR change events for a
* short period of time.
****************************************************************/
InterferenceHelper::NiChange::NiChange (double power, Ptr<Event> event)
: m_power (power),
m_event (event)
{
}
double
InterferenceHelper::NiChange::GetPower (void) const
{
return m_power;
}
void
InterferenceHelper::NiChange::AddPower (double power)
{
m_power += power;
}
Ptr<Event>
InterferenceHelper::NiChange::GetEvent (void) const
{
return m_event;
}
/****************************************************************
* The actual InterferenceHelper
****************************************************************/
InterferenceHelper::InterferenceHelper ()
: m_errorRateModel (0),
m_numRxAntennas (1),
m_firstPower (0),
m_rxing (false)
{
// Always have a zero power noise event in the list
AddNiChangeEvent (Time (0), NiChange (0.0, 0));
}
InterferenceHelper::~InterferenceHelper ()
{
EraseEvents ();
m_errorRateModel = 0;
}
Ptr<Event>
InterferenceHelper::Add (Ptr<const Packet> packet, WifiTxVector txVector, Time duration, double rxPowerW)
{
Ptr<Event> event = Create<Event> (packet, txVector, duration, rxPowerW);
AppendEvent (event);
return event;
}
void
InterferenceHelper::AddForeignSignal (Time duration, double rxPowerW)
{
// Parameters other than duration and rxPowerW are unused for this type
// of signal, so we provide dummy versions
WifiTxVector fakeTxVector;
Ptr<const Packet> packet (0);
Add (packet, fakeTxVector, duration, rxPowerW);
}
void
InterferenceHelper::SetNoiseFigure (double value)
{
m_noiseFigure = value;
}
void
InterferenceHelper::SetErrorRateModel (const Ptr<ErrorRateModel> rate)
{
m_errorRateModel = rate;
}
Ptr<ErrorRateModel>
InterferenceHelper::GetErrorRateModel (void) const
{
return m_errorRateModel;
}
void
InterferenceHelper::SetNumberOfReceiveAntennas (uint8_t rx)
{
m_numRxAntennas = rx;
}
Time
InterferenceHelper::GetEnergyDuration (double energyW) const
{
Time now = Simulator::Now ();
auto i = GetPreviousPosition (now);
Time end = i->first;
for (; i != m_niChanges.end (); ++i)
{
double noiseInterferenceW = i->second.GetPower ();
end = i->first;
if (noiseInterferenceW < energyW)
{
break;
}
}
return end > now ? end - now : MicroSeconds (0);
}
void
InterferenceHelper::AppendEvent (Ptr<Event> event)
{
NS_LOG_FUNCTION (this);
double previousPowerStart = 0;
double previousPowerEnd = 0;
previousPowerStart = GetPreviousPosition (event->GetStartTime ())->second.GetPower ();
previousPowerEnd = GetPreviousPosition (event->GetEndTime ())->second.GetPower ();
if (!m_rxing)
{
m_firstPower = previousPowerStart;
// Always leave the first zero power noise event in the list
m_niChanges.erase (++(m_niChanges.begin ()),
GetNextPosition (event->GetStartTime ()));
}
auto first = AddNiChangeEvent (event->GetStartTime (), NiChange (previousPowerStart, event));
auto last = AddNiChangeEvent (event->GetEndTime (), NiChange (previousPowerEnd, event));
for (auto i = first; i != last; ++i)
{
i->second.AddPower (event->GetRxPowerW ());
}
}
double
InterferenceHelper::CalculateSnr (double signal, double noiseInterference, uint16_t channelWidth) const
{
//thermal noise at 290K in J/s = W
static const double BOLTZMANN = 1.3803e-23;
//Nt is the power of thermal noise in W
double Nt = BOLTZMANN * 290 * channelWidth * 1e6;
//receiver noise Floor (W) which accounts for thermal noise and non-idealities of the receiver
double noiseFloor = m_noiseFigure * Nt;
double noise = noiseFloor + noiseInterference;
double snr = signal / noise; //linear scale
NS_LOG_DEBUG ("bandwidth(MHz)=" << channelWidth << ", signal(W)= " << signal << ", noise(W)=" << noiseFloor << ", interference(W)=" << noiseInterference << ", snr(linear)=" << snr);
return snr;
}
double
InterferenceHelper::CalculateNoiseInterferenceW (Ptr<Event> event, NiChanges *ni) const
{
double noiseInterference = m_firstPower;
auto it = m_niChanges.find (event->GetStartTime ());
for (; it != m_niChanges.end () && it->second.GetEvent () != event; ++it)
{
noiseInterference = it->second.GetPower ();
}
ni->emplace (event->GetStartTime (), NiChange (0, event));
while (++it != m_niChanges.end () && it->second.GetEvent () != event)
{
ni->insert (*it);
}
ni->emplace (event->GetEndTime (), NiChange (0, event));
return noiseInterference;
}
double
InterferenceHelper::CalculateChunkSuccessRate (double snir, Time duration, WifiMode mode, WifiTxVector txVector) const
{
if (duration.IsZero ())
{
return 1.0;
}
uint64_t rate = mode.GetPhyRate (txVector);
uint64_t nbits = static_cast<uint64_t> (rate * duration.GetSeconds ());
if (txVector.GetMode ().GetModulationClass () == WIFI_MOD_CLASS_HT || txVector.GetMode ().GetModulationClass () == WIFI_MOD_CLASS_VHT || txVector.GetMode ().GetModulationClass () == WIFI_MOD_CLASS_HE)
{
nbits /= txVector.GetNss (); //divide effective number of bits by NSS to achieve same chunk error rate as SISO for AWGN
double gain = (txVector.GetNTx () * m_numRxAntennas); //compute gain offered by MIMO, SIMO or MISO compared to SISO for AWGN
NS_LOG_DEBUG ("TX=" << +txVector.GetNTx () <<
", RX=" << +m_numRxAntennas <<
", SNIR improvement=+" << 10 * std::log10 (gain) << "dB");
snir *= gain;
}
double csr = m_errorRateModel->GetChunkSuccessRate (mode, txVector, snir, nbits);
return csr;
}
double
InterferenceHelper::CalculatePlcpPayloadPer (Ptr<const Event> event, NiChanges *ni) const
{
NS_LOG_FUNCTION (this);
const WifiTxVector txVector = event->GetTxVector ();
double psr = 1.0; /* Packet Success Rate */
auto j = ni->begin ();
Time previous = j->first;
WifiMode payloadMode = event->GetPayloadMode ();
WifiPreamble preamble = txVector.GetPreambleType ();
Time plcpHeaderStart = j->first + WifiPhy::GetPlcpPreambleDuration (txVector); //packet start time + preamble
Time plcpHsigHeaderStart = plcpHeaderStart + WifiPhy::GetPlcpHeaderDuration (txVector); //packet start time + preamble + L-SIG
Time plcpTrainingSymbolsStart = plcpHsigHeaderStart + WifiPhy::GetPlcpHtSigHeaderDuration (preamble) + WifiPhy::GetPlcpSigA1Duration (preamble) + WifiPhy::GetPlcpSigA2Duration (preamble); //packet start time + preamble + L-SIG + HT-SIG or SIG-A
Time plcpPayloadStart = plcpTrainingSymbolsStart + WifiPhy::GetPlcpTrainingSymbolDuration (txVector) + WifiPhy::GetPlcpSigBDuration (preamble); //packet start time + preamble + L-SIG + HT-SIG or SIG-A + Training + SIG-B
double noiseInterferenceW = m_firstPower;
double powerW = event->GetRxPowerW ();
while (++j != ni->end ())
{
Time current = j->first;
NS_LOG_DEBUG ("previous= " << previous << ", current=" << current);
NS_ASSERT (current >= previous);
//Case 1: Both previous and current point to the payload
if (previous >= plcpPayloadStart)
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
current - previous,
payloadMode, txVector);
NS_LOG_DEBUG ("Both previous and current point to the payload: mode=" << payloadMode << ", psr=" << psr);
}
//Case 2: previous is before payload and current is in the payload
else if (current >= plcpPayloadStart)
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
current - plcpPayloadStart,
payloadMode, txVector);
NS_LOG_DEBUG ("previous is before payload and current is in the payload: mode=" << payloadMode << ", psr=" << psr);
}
noiseInterferenceW = j->second.GetPower () - powerW;
previous = j->first;
}
double per = 1 - psr;
return per;
}
double
InterferenceHelper::CalculatePlcpHeaderPer (Ptr<const Event> event, NiChanges *ni) const
{
NS_LOG_FUNCTION (this);
const WifiTxVector txVector = event->GetTxVector ();
double psr = 1.0; /* Packet Success Rate */
auto j = ni->begin ();
Time previous = j->first;
WifiPreamble preamble = txVector.GetPreambleType ();
WifiMode mcsHeaderMode;
if (preamble == WIFI_PREAMBLE_HT_MF || preamble == WIFI_PREAMBLE_HT_GF)
{
//mode for PLCP header fields sent with HT modulation
mcsHeaderMode = WifiPhy::GetHtPlcpHeaderMode ();
}
else if (preamble == WIFI_PREAMBLE_VHT)
{
//mode for PLCP header fields sent with VHT modulation
mcsHeaderMode = WifiPhy::GetVhtPlcpHeaderMode ();
}
else if (preamble == WIFI_PREAMBLE_HE_SU)
{
//mode for PLCP header fields sent with HE modulation
mcsHeaderMode = WifiPhy::GetHePlcpHeaderMode ();
}
WifiMode headerMode = WifiPhy::GetPlcpHeaderMode (txVector);
Time plcpHeaderStart = j->first + WifiPhy::GetPlcpPreambleDuration (txVector); //packet start time + preamble
Time plcpHsigHeaderStart = plcpHeaderStart + WifiPhy::GetPlcpHeaderDuration (txVector); //packet start time + preamble + L-SIG
Time plcpTrainingSymbolsStart = plcpHsigHeaderStart + WifiPhy::GetPlcpHtSigHeaderDuration (preamble) + WifiPhy::GetPlcpSigA1Duration (preamble) + WifiPhy::GetPlcpSigA2Duration (preamble); //packet start time + preamble + L-SIG + HT-SIG or SIG-A
Time plcpPayloadStart = plcpTrainingSymbolsStart + WifiPhy::GetPlcpTrainingSymbolDuration (txVector) + WifiPhy::GetPlcpSigBDuration (preamble); //packet start time + preamble + L-SIG + HT-SIG or SIG-A + Training + SIG-B
double noiseInterferenceW = m_firstPower;
double powerW = event->GetRxPowerW ();
while (++j != ni->end ())
{
Time current = j->first;
NS_LOG_DEBUG ("previous= " << previous << ", current=" << current);
NS_ASSERT (current >= previous);
//Case 1: previous and current after playload start: nothing to do
if (previous >= plcpPayloadStart)
{
psr *= 1;
NS_LOG_DEBUG ("Case 1 - previous and current after playload start: nothing to do");
}
//Case 2: previous is in training or in SIG-B: legacy will not enter here since it didn't enter in the last two and they are all the same for legacy
else if (previous >= plcpTrainingSymbolsStart)
{
NS_ASSERT ((preamble != WIFI_PREAMBLE_LONG) && (preamble != WIFI_PREAMBLE_SHORT));
//Case 2a: current after payload start
if (current >= plcpPayloadStart)
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpPayloadStart - previous,
mcsHeaderMode, txVector);
NS_LOG_DEBUG ("Case 2a - previous is in training or in SIG-B and current after payload start: mode=" << mcsHeaderMode << ", psr=" << psr);
}
//Case 2b: current is in training or in SIG-B
else
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
current - previous,
mcsHeaderMode, txVector);
NS_LOG_DEBUG ("Case 2b - previous is in training or in SIG-B and current is in training or in SIG-B: mode=" << mcsHeaderMode << ", psr=" << psr);
}
}
//Case 3: previous is in HT-SIG or SIG-A: legacy will not enter here since it didn't enter in the last two and they are all the same for legacy
else if (previous >= plcpHsigHeaderStart)
{
NS_ASSERT ((preamble != WIFI_PREAMBLE_LONG) && (preamble != WIFI_PREAMBLE_SHORT));
//Case 3a: current after payload start
if (current >= plcpPayloadStart)
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpPayloadStart - plcpTrainingSymbolsStart,
mcsHeaderMode, txVector);
//Case 3ai: VHT or HE format
if (preamble == WIFI_PREAMBLE_VHT || preamble == WIFI_PREAMBLE_HE_SU)
{
//SIG-A is sent using legacy OFDM modulation
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpTrainingSymbolsStart - previous,
headerMode, txVector);
NS_LOG_DEBUG ("Case 3ai - previous is in SIG-A and current after payload start: mcs mode=" << mcsHeaderMode << ", legacy mode=" << headerMode << ", psr=" << psr);
}
//Case 3aii: HT formats
else
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpTrainingSymbolsStart - previous,
mcsHeaderMode, txVector);
NS_LOG_DEBUG ("Case 3aii - previous is in HT-SIG and current after payload start: mode=" << mcsHeaderMode << ", psr=" << psr);
}
}
//Case 3b: current is in training or in SIG-B
else if (current >= plcpTrainingSymbolsStart)
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
current - plcpTrainingSymbolsStart,
mcsHeaderMode, txVector);
//Case 3bi: VHT or HE format
if (preamble == WIFI_PREAMBLE_VHT || preamble == WIFI_PREAMBLE_HE_SU)
{
//SIG-A is sent using legacy OFDM modulation
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpTrainingSymbolsStart - previous,
headerMode, txVector);
NS_LOG_DEBUG ("Case 3bi - previous is in SIG-A and current is in training or in SIG-B: mode=" << headerMode << ", psr=" << psr);
}
//Case 3bii: HT formats
else
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpTrainingSymbolsStart - previous,
mcsHeaderMode, txVector);
NS_LOG_DEBUG ("Case 3bii - previous is in HT-SIG and current is in HT training: mode=" << mcsHeaderMode << ", psr=" << psr);
}
}
//Case 3c: current with previous in HT-SIG or SIG-A
else
{
//Case 3ci: VHT or HE format
if (preamble == WIFI_PREAMBLE_VHT || preamble == WIFI_PREAMBLE_HE_SU)
{
//SIG-A is sent using legacy OFDM modulation
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
current - previous,
headerMode, txVector);
NS_LOG_DEBUG ("Case 3ci - previous with current in SIG-A: mode=" << headerMode << ", psr=" << psr);
}
//Case 3cii: HT mixed format or HT greenfield
else
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
current - previous,
mcsHeaderMode, txVector);
NS_LOG_DEBUG ("Case 3cii - previous with current in HT-SIG: mode=" << mcsHeaderMode << ", psr=" << psr);
}
}
}
//Case 4: previous in L-SIG: HT GF will not reach here because it will execute the previous if and exit
else if (previous >= plcpHeaderStart)
{
NS_ASSERT (preamble != WIFI_PREAMBLE_HT_GF);
//Case 4a: current after payload start
if (current >= plcpPayloadStart)
{
//Case 4ai: legacy format
if (preamble == WIFI_PREAMBLE_LONG || preamble == WIFI_PREAMBLE_SHORT)
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpPayloadStart - previous,
headerMode, txVector);
NS_LOG_DEBUG ("Case 4ai - previous in L-SIG and current after payload start: mode=" << headerMode << ", psr=" << psr);
}
//Case 4aii: VHT or HE format
else if (preamble == WIFI_PREAMBLE_VHT || preamble == WIFI_PREAMBLE_HE_SU)
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpPayloadStart - plcpTrainingSymbolsStart,
mcsHeaderMode, txVector);
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpTrainingSymbolsStart - previous,
headerMode, txVector);
NS_LOG_DEBUG ("Case 4aii - previous is in L-SIG and current after payload start: mcs mode=" << mcsHeaderMode << ", legacy mode=" << headerMode << ", psr=" << psr);
}
//Case 4aiii: HT mixed format
else
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpPayloadStart - plcpHsigHeaderStart,
mcsHeaderMode, txVector);
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpHsigHeaderStart - previous,
headerMode, txVector);
NS_LOG_DEBUG ("Case 4aiii - previous in L-SIG and current after payload start: mcs mode=" << mcsHeaderMode << ", legacy mode=" << headerMode << ", psr=" << psr);
}
}
//Case 4b: current is in training or in SIG-B. legacy will not come here since it went in previous if or if the previous if is not true this will be not true
else if (current >= plcpTrainingSymbolsStart)
{
NS_ASSERT ((preamble != WIFI_PREAMBLE_LONG) && (preamble != WIFI_PREAMBLE_SHORT));
//Case 4bi: VHT or HE format
if (preamble == WIFI_PREAMBLE_VHT || preamble == WIFI_PREAMBLE_HE_SU)
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
current - plcpTrainingSymbolsStart,
mcsHeaderMode, txVector);
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpTrainingSymbolsStart - previous,
headerMode, txVector);
NS_LOG_DEBUG ("Case 4bi - previous is in L-SIG and current in training or in SIG-B: mcs mode=" << mcsHeaderMode << ", legacy mode=" << headerMode << ", psr=" << psr);
}
//Case 4bii: HT mixed format
else
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
current - plcpHsigHeaderStart,
mcsHeaderMode, txVector);
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpHsigHeaderStart - previous,
headerMode, txVector);
NS_LOG_DEBUG ("Case 4bii - previous in L-SIG and current in HT training: mcs mode=" << mcsHeaderMode << ", legacy mode=" << headerMode << ", psr=" << psr);
}
}
//Case 4c: current in HT-SIG or in SIG-A. Legacy will not come here since it went in previous if or if the previous if is not true this will be not true
else if (current >= plcpHsigHeaderStart)
{
NS_ASSERT ((preamble != WIFI_PREAMBLE_LONG) && (preamble != WIFI_PREAMBLE_SHORT));
//Case 4ci: VHT format
if (preamble == WIFI_PREAMBLE_VHT || preamble == WIFI_PREAMBLE_HE_SU)
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
current - previous,
headerMode, txVector);
NS_LOG_DEBUG ("Case 4ci - previous is in L-SIG and current in SIG-A: mode=" << headerMode << ", psr=" << psr);
}
//Case 4cii: HT mixed format
else
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
current - plcpHsigHeaderStart,
mcsHeaderMode, txVector);
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpHsigHeaderStart - previous,
headerMode, txVector);
NS_LOG_DEBUG ("Case 4cii - previous in L-SIG and current in HT-SIG: mcs mode=" << mcsHeaderMode << ", legacy mode=" << headerMode << ", psr=" << psr);
}
}
//Case 4d: current with previous in L-SIG
else
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
current - previous,
headerMode, txVector);
NS_LOG_DEBUG ("Case 4d - current with previous in L-SIG: mode=" << headerMode << ", psr=" << psr);
}
}
//Case 5: previous is in the preamble works for all cases
else
{
//Case 5a: current after payload start
if (current >= plcpPayloadStart)
{
//Case 5ai: legacy format (No HT-SIG or Training Symbols)
if (preamble == WIFI_PREAMBLE_LONG || preamble == WIFI_PREAMBLE_SHORT)
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpPayloadStart - plcpHeaderStart,
headerMode, txVector);
NS_LOG_DEBUG ("Case 5a - previous is in the preamble and current is after payload start: mode=" << headerMode << ", psr=" << psr);
}
//Case 5aii: VHT or HE format
else if (preamble == WIFI_PREAMBLE_VHT || preamble == WIFI_PREAMBLE_HE_SU)
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpPayloadStart - plcpTrainingSymbolsStart,
mcsHeaderMode, txVector);
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpTrainingSymbolsStart - plcpHeaderStart,
headerMode, txVector);
NS_LOG_DEBUG ("Case 5aii - previous is in the preamble and current is after payload start: mcs mode=" << mcsHeaderMode << ", legacy mode=" << headerMode << ", psr=" << psr);
}
//Case 5aiii: HT formats
else
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpPayloadStart - plcpHsigHeaderStart,
mcsHeaderMode, txVector);
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpHsigHeaderStart - plcpHeaderStart, //HT GF: plcpHsigHeaderStart - plcpHeaderStart = 0
headerMode, txVector);
NS_LOG_DEBUG ("Case 5aiii - previous is in the preamble and current is after payload start: mcs mode=" << mcsHeaderMode << ", legacy mode=" << headerMode << ", psr=" << psr);
}
}
//Case 5b: current is in training or in SIG-B. Legacy will not come here since it went in previous if or if the previous if is not true this will be not true
else if (current >= plcpTrainingSymbolsStart)
{
NS_ASSERT ((preamble != WIFI_PREAMBLE_LONG) && (preamble != WIFI_PREAMBLE_SHORT));
//Case 5bi: VHT or HE format
if (preamble == WIFI_PREAMBLE_VHT || preamble == WIFI_PREAMBLE_HE_SU)
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
current - plcpTrainingSymbolsStart,
mcsHeaderMode, txVector);
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpTrainingSymbolsStart - plcpHeaderStart,
headerMode, txVector);
NS_LOG_DEBUG ("Case 5bi - previous is in the preamble and current in training or in SIG-B: mcs mode=" << mcsHeaderMode << ", legacy mode=" << headerMode << ", psr=" << psr);
}
//Case 5bii: HT mixed format
else
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
current - plcpHsigHeaderStart,
mcsHeaderMode, txVector);
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpHsigHeaderStart - plcpHeaderStart,
headerMode, txVector);
NS_LOG_DEBUG ("Case 5bii - previous is in the preamble and current in HT training: mcs mode=" << mcsHeaderMode << ", legacy mode=" << headerMode << ", psr=" << psr);
}
}
//Case 5c: current in HT-SIG or in SIG-A. Legacy will not come here since it went in previous if or if the previous if is not true this will be not true
else if (current >= plcpHsigHeaderStart)
{
NS_ASSERT ((preamble != WIFI_PREAMBLE_LONG) && (preamble != WIFI_PREAMBLE_SHORT));
//Case 5ci: VHT or HE format
if (preamble == WIFI_PREAMBLE_VHT || preamble == WIFI_PREAMBLE_HE_SU)
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
current - plcpHeaderStart,
headerMode, txVector);
NS_LOG_DEBUG ("Case 5ci - previous is in preamble and current in SIG-A: mode=" << headerMode << ", psr=" << psr);
}
//Case 5cii: HT formats
else
{
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
current - plcpHsigHeaderStart,
mcsHeaderMode, txVector);
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
plcpHsigHeaderStart - plcpHeaderStart, //HT-GF: plcpHsigHeaderStart - plcpHeaderStart = 0
headerMode, txVector);
NS_LOG_DEBUG ("Case 5cii - previous in preamble and current in HT-SIG: mcs mode=" << mcsHeaderMode << ", legacy mode=" << headerMode << ", psr=" << psr);
}
}
//Case 5d: current is in L-SIG. HT-GF will not come here
else if (current >= plcpHeaderStart)
{
NS_ASSERT (preamble != WIFI_PREAMBLE_HT_GF);
psr *= CalculateChunkSuccessRate (CalculateSnr (powerW,
noiseInterferenceW,
txVector.GetChannelWidth ()),
current - plcpHeaderStart,
headerMode, txVector);
NS_LOG_DEBUG ("Case 5d - previous is in the preamble and current is in L-SIG: mode=" << headerMode << ", psr=" << psr);
}
}
noiseInterferenceW = j->second.GetPower () - powerW;
previous = j->first;
}
double per = 1 - psr;
return per;
}
struct InterferenceHelper::SnrPer
InterferenceHelper::CalculatePlcpPayloadSnrPer (Ptr<Event> event) const
{
NiChanges ni;
double noiseInterferenceW = CalculateNoiseInterferenceW (event, &ni);
double snr = CalculateSnr (event->GetRxPowerW (),
noiseInterferenceW,
event->GetTxVector ().GetChannelWidth ());
/* calculate the SNIR at the start of the packet and accumulate
* all SNIR changes in the snir vector.
*/
double per = CalculatePlcpPayloadPer (event, &ni);
struct SnrPer snrPer;
snrPer.snr = snr;
snrPer.per = per;
return snrPer;
}
struct InterferenceHelper::SnrPer
InterferenceHelper::CalculatePlcpHeaderSnrPer (Ptr<Event> event) const
{
NiChanges ni;
double noiseInterferenceW = CalculateNoiseInterferenceW (event, &ni);
double snr = CalculateSnr (event->GetRxPowerW (),
noiseInterferenceW,
event->GetTxVector ().GetChannelWidth ());
/* calculate the SNIR at the start of the plcp header and accumulate
* all SNIR changes in the snir vector.
*/
double per = CalculatePlcpHeaderPer (event, &ni);
struct SnrPer snrPer;
snrPer.snr = snr;
snrPer.per = per;
return snrPer;
}
void
InterferenceHelper::EraseEvents (void)
{
m_niChanges.clear ();
// Always have a zero power noise event in the list
AddNiChangeEvent (Time (0), NiChange (0.0, 0));
m_rxing = false;
m_firstPower = 0;
}
InterferenceHelper::NiChanges::const_iterator
InterferenceHelper::GetNextPosition (Time moment) const
{
return m_niChanges.upper_bound (moment);
}
InterferenceHelper::NiChanges::const_iterator
InterferenceHelper::GetPreviousPosition (Time moment) const
{
auto it = GetNextPosition (moment);
// This is safe since there is always an NiChange at time 0,
// before moment.
--it;
return it;
}
InterferenceHelper::NiChanges::iterator
InterferenceHelper::AddNiChangeEvent (Time moment, NiChange change)
{
return m_niChanges.insert (GetNextPosition (moment), std::make_pair (moment, change));
}
void
InterferenceHelper::NotifyRxStart ()
{
NS_LOG_FUNCTION (this);
m_rxing = true;
}
void
InterferenceHelper::NotifyRxEnd ()
{
NS_LOG_FUNCTION (this);
m_rxing = false;
//Update m_firstPower for frame capture
auto it = m_niChanges.find (Simulator::Now ());
it--;
m_firstPower = it->second.GetPower ();
}
} //namespace ns3