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wifi: Add function to return the symbol duration

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This commit is contained in:
Sebastien Deronne
2022-06-20 18:07:36 +02:00
parent 250e5745fd
commit fe6149948e
7 changed files with 89 additions and 37 deletions
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10
src/wifi/model/he/he-phy.cc
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@@ -316,7 +316,7 @@ HePhy::GetSymbolDuration (const WifiTxVector& txVector) const
{
uint16_t gi = txVector.GetGuardInterval ();
NS_ASSERT (gi == 800 || gi == 1600 || gi == 3200);
return NanoSeconds (12800 + gi);
return GetSymbolDuration (NanoSeconds (gi));
}
void
@@ -1229,7 +1229,7 @@ HePhy::GetDataRate (uint8_t mcsValue, uint16_t channelWidth, uint16_t guardInter
{
NS_ASSERT (guardInterval == 800 || guardInterval == 1600 || guardInterval == 3200);
NS_ASSERT (nss <= 8);
return HtPhy::CalculateDataRate (12.8, guardInterval,
return HtPhy::CalculateDataRate (GetSymbolDuration (NanoSeconds (guardInterval)),
GetUsableSubcarriers (channelWidth),
static_cast<uint16_t> (log2 (GetConstellationSize (mcsValue))),
HtPhy::GetCodeRatio (GetCodeRate (mcsValue)), nss);
@@ -1258,6 +1258,12 @@ HePhy::GetUsableSubcarriers (uint16_t channelWidth)
}
}
Time
HePhy::GetSymbolDuration (Time guardInterval)
{
return NanoSeconds (12800) + guardInterval;
}
uint64_t
HePhy::GetNonHtReferenceRate (uint8_t mcsValue)
{

9
src/wifi/model/he/he-phy.h
View File

@@ -422,12 +422,19 @@ protected:
* and lookup in Table 10-10 of IEEE P802.11ax/D6.0.
*/
static uint64_t CalculateNonHtReferenceRate (WifiCodeRate codeRate, uint16_t constellationSize);
/**
* \param channelWidth the channel width in MHz
* \return he number of usable subcarriers for data
* \return the number of usable subcarriers for data
*/
static uint16_t GetUsableSubcarriers (uint16_t channelWidth);
/**
* \param guardInterval the guard interval duration
* \return the symbol duration
*/
static Time GetSymbolDuration (Time guardInterval);
uint64_t m_previouslyTxPpduUid; //!< UID of the previously sent PPDU, used by AP to recognize response HE TB PPDUs
uint64_t m_currentHeTbPpduUid; //!< UID of the HE TB PPDU being received

17
src/wifi/model/ht/ht-phy.cc
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@@ -666,19 +666,20 @@ HtPhy::GetDataRate (uint8_t mcsValue, uint16_t channelWidth, uint16_t guardInter
{
NS_ASSERT (guardInterval == 800 || guardInterval == 400);
NS_ASSERT (nss <= 4);
return CalculateDataRate (3.2, guardInterval,
return CalculateDataRate (GetSymbolDuration (NanoSeconds (guardInterval)),
GetUsableSubcarriers (channelWidth),
static_cast<uint16_t> (log2 (GetHtConstellationSize (mcsValue))),
GetCodeRatio (GetHtCodeRate (mcsValue)), nss);
}
uint64_t
HtPhy::CalculateDataRate (double symbolDuration, uint16_t guardInterval,
uint16_t usableSubCarriers, uint16_t numberOfBitsPerSubcarrier,
HtPhy::CalculateDataRate (Time symbolDuration, uint16_t usableSubCarriers,
uint16_t numberOfBitsPerSubcarrier,
double codingRate, uint8_t nss)
{
return nss * OfdmPhy::CalculateDataRate (symbolDuration, guardInterval,
usableSubCarriers, numberOfBitsPerSubcarrier,
return nss * OfdmPhy::CalculateDataRate (symbolDuration,
usableSubCarriers,
numberOfBitsPerSubcarrier,
codingRate);
}
@@ -688,6 +689,12 @@ HtPhy::GetUsableSubcarriers (uint16_t channelWidth)
return (channelWidth == 40) ? 108 : 52;
}
Time
HtPhy::GetSymbolDuration (Time guardInterval)
{
return NanoSeconds (3200) + guardInterval;
}
uint64_t
HtPhy::GetNonHtReferenceRate (uint8_t mcsValue)
{

22
src/wifi/model/ht/ht-phy.h
View File

@@ -505,8 +505,7 @@ protected:
/**
* Calculates data rate from the supplied parameters.
*
* \param symbolDuration the symbol duration (in us) excluding guard interval
* \param guardInterval the considered guard interval duration in nanoseconds
* \param symbolDuration the symbol duration
* \param usableSubCarriers the number of usable subcarriers for data
* \param numberOfBitsPerSubcarrier the number of data bits per subcarrier
* \param codingRate the coding rate
@@ -514,15 +513,28 @@ protected:
*
* \return the data bit rate of this signal in bps.
*/
static uint64_t CalculateDataRate (double symbolDuration, uint16_t guardInterval,
uint16_t usableSubCarriers, uint16_t numberOfBitsPerSubcarrier,
static uint64_t CalculateDataRate (Time symbolDuration, uint16_t usableSubCarriers,
uint16_t numberOfBitsPerSubcarrier,
double codingRate, uint8_t nss);
/**
* \param channelWidth the channel width in MHz
* \return he number of usable subcarriers for data
* \return the symbol duration excluding guard interval
*/
static Time GetSymbolDuration (uint16_t channelWidth);
/**
* \param channelWidth the channel width in MHz
* \return the number of usable subcarriers for data
*/
static uint16_t GetUsableSubcarriers (uint16_t channelWidth);
/**
* \param guardInterval the guard interval duration
* \return the symbol duration
*/
static Time GetSymbolDuration (Time guardInterval);
uint8_t m_maxMcsIndexPerSs; //!< the maximum MCS index per spatial stream as defined by the standard
uint8_t m_maxSupportedMcsIndexPerSs; //!< the maximum supported MCS index per spatial stream
uint8_t m_bssMembershipSelector; //!< the BSS membership selector

46
src/wifi/model/non-ht/ofdm-phy.cc
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@@ -568,32 +568,42 @@ OfdmPhy::GetDataRate (const std::string& name, uint16_t channelWidth)
uint64_t
OfdmPhy::CalculateDataRate (WifiCodeRate codeRate, uint16_t constellationSize, uint16_t channelWidth)
{
double symbolDuration = 3.2; //in us
uint16_t guardInterval = 800; //in ns
if (channelWidth == 10)
{
symbolDuration = 6.4;
guardInterval = 1600;
}
else if (channelWidth == 5)
{
symbolDuration = 12.8;
guardInterval = 3200;
}
return CalculateDataRate (symbolDuration, guardInterval,
48, static_cast<uint16_t> (log2 (constellationSize)),
return CalculateDataRate (GetSymbolDuration (channelWidth),
GetUsableSubcarriers (),
static_cast<uint16_t> (log2 (constellationSize)),
GetCodeRatio (codeRate));
}
uint64_t
OfdmPhy::CalculateDataRate (double symbolDuration, uint16_t guardInterval,
uint16_t usableSubCarriers, uint16_t numberOfBitsPerSubcarrier,
double codingRate)
OfdmPhy::CalculateDataRate (Time symbolDuration, uint16_t usableSubCarriers,
uint16_t numberOfBitsPerSubcarrier, double codingRate)
{
double symbolRate = (1 / (symbolDuration + (static_cast<double> (guardInterval) / 1000))) * 1e6;
double symbolRate = (1e9 / static_cast<double> (symbolDuration.GetNanoSeconds ()));
return lrint (ceil (symbolRate * usableSubCarriers * numberOfBitsPerSubcarrier * codingRate));
}
uint16_t
OfdmPhy::GetUsableSubcarriers (void)
{
return 48;
}
Time
OfdmPhy::GetSymbolDuration (uint16_t channelWidth)
{
Time symbolDuration = MicroSeconds (4);
uint8_t bwFactor = 1;
if (channelWidth == 10)
{
bwFactor = 2;
}
else if (channelWidth == 5)
{
bwFactor = 4;
}
return bwFactor * symbolDuration;
}
bool
OfdmPhy::IsAllowed (const WifiTxVector& /*txVector*/)
{

20
src/wifi/model/non-ht/ofdm-phy.h
View File

@@ -402,17 +402,27 @@ protected:
/**
* Calculates data rate from the supplied parameters.
*
* \param symbolDuration the symbol duration (in us) excluding guard interval
* \param guardInterval the considered guard interval duration in nanoseconds
* \param symbolDuration the symbol duration
* \param usableSubCarriers the number of usable subcarriers for data
* \param numberOfBitsPerSubcarrier the number of data bits per subcarrier
* \param codingRate the coding rate
*
* \return the data bit rate of this signal in bps.
*/
static uint64_t CalculateDataRate (double symbolDuration, uint16_t guardInterval,
uint16_t usableSubCarriers, uint16_t numberOfBitsPerSubcarrier,
double codingRate);
static uint64_t CalculateDataRate (Time symbolDuration, uint16_t usableSubCarriers,
uint16_t numberOfBitsPerSubcarrier, double codingRate);
/**
* \return the number of usable subcarriers for data
*/
static uint16_t GetUsableSubcarriers (void);
/**
* \param channelWidth the channel width in MHz
* \return the symbol duration
*/
static Time GetSymbolDuration (uint16_t channelWidth);
private:
/**

2
src/wifi/model/vht/vht-phy.cc
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@@ -470,7 +470,7 @@ VhtPhy::GetDataRate (uint8_t mcsValue, uint16_t channelWidth, uint16_t guardInte
NS_ASSERT (guardInterval == 800 || guardInterval == 400);
NS_ASSERT (nss <= 8);
NS_ASSERT_MSG (IsCombinationAllowed (mcsValue, channelWidth, nss), "VHT MCS " << +mcsValue << " forbidden at " << channelWidth << " MHz when NSS is " << +nss);
return HtPhy::CalculateDataRate (3.2, guardInterval,
return HtPhy::CalculateDataRate (GetSymbolDuration (NanoSeconds (guardInterval)),
GetUsableSubcarriers (channelWidth),
static_cast<uint16_t> (log2 (GetConstellationSize (mcsValue))),
HtPhy::GetCodeRatio (GetCodeRate (mcsValue)), nss);