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wifi: Rework conversion from RU subcarriers to the indices used by the Spectrum model

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This commit is contained in:
Sébastien Deronne
2024-12-04 15:11:00 +01:00
parent 302cc5bbc4
commit a9e64e0d94
4 changed files with 48 additions and 61 deletions
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71
src/wifi/model/he/he-phy.cc
View File

@@ -992,13 +992,13 @@ HePhy::GetRuBandForTx(const WifiTxVector& txVector, uint16_t staId) const
WIFI_MOD_CLASS_HE);
// for a TX spectrum, the guard bandwidth is a function of the transmission channel width
// and the spectrum width equals the transmission channel width (hence bandIndex equals 0)
const auto indices = ConvertHeRuSubcarriers(channelWidth,
GetGuardBandwidth(channelWidth),
m_wifiPhy->GetOperatingChannel().GetFrequencies(),
m_wifiPhy->GetChannelWidth(),
m_wifiPhy->GetSubcarrierSpacing(),
{group.front().first, group.back().second},
0);
const auto indices = ConvertRuSubcarriers(channelWidth,
GetGuardBandwidth(channelWidth),
m_wifiPhy->GetOperatingChannel().GetFrequencies(),
m_wifiPhy->GetChannelWidth(),
m_wifiPhy->GetSubcarrierSpacing(),
{group.front().first, group.back().second},
0);
WifiSpectrumBandInfo ruBandForTx{};
for (const auto& indicesPerSegment : indices)
{
@@ -1025,14 +1025,14 @@ HePhy::GetRuBandForRx(const WifiTxVector& txVector, uint16_t staId) const
WIFI_MOD_CLASS_HE);
// for an RX spectrum, the guard bandwidth is a function of the operating channel width
// and the spectrum width equals the operating channel width
const auto indices = ConvertHeRuSubcarriers(
channelWidth,
GetGuardBandwidth(m_wifiPhy->GetChannelWidth()),
m_wifiPhy->GetOperatingChannel().GetFrequencies(),
m_wifiPhy->GetChannelWidth(),
m_wifiPhy->GetSubcarrierSpacing(),
{group.front().first, group.back().second},
m_wifiPhy->GetOperatingChannel().GetPrimaryChannelIndex(channelWidth));
const auto indices =
ConvertRuSubcarriers(channelWidth,
GetGuardBandwidth(m_wifiPhy->GetChannelWidth()),
m_wifiPhy->GetOperatingChannel().GetFrequencies(),
m_wifiPhy->GetChannelWidth(),
m_wifiPhy->GetSubcarrierSpacing(),
{group.front().first, group.back().second},
m_wifiPhy->GetOperatingChannel().GetPrimaryChannelIndex(channelWidth));
WifiSpectrumBandInfo ruBandForRx{};
for (const auto& indicesPerSegment : indices)
{
@@ -1821,13 +1821,13 @@ HePhy::GetRxPpduFromTxPpdu(Ptr<const WifiPpdu> ppdu)
}
std::vector<WifiSpectrumBandIndices>
HePhy::ConvertHeRuSubcarriers(MHz_u bandWidth,
MHz_u guardBandwidth,
const std::vector<MHz_u>& centerFrequencies,
MHz_u totalWidth,
Hz_u subcarrierSpacing,
SubcarrierRange subcarrierRange,
uint8_t bandIndex)
HePhy::ConvertRuSubcarriers(MHz_u bandWidth,
MHz_u guardBandwidth,
const std::vector<MHz_u>& centerFrequencies,
MHz_u totalWidth,
Hz_u subcarrierSpacing,
SubcarrierRange subcarrierRange,
uint8_t bandIndex)
{
NS_ASSERT_MSG(bandWidth <= totalWidth,
"Bandwidth (" << bandWidth << ") cannot exceed total operating channel width ("
@@ -1841,26 +1841,13 @@ HePhy::ConvertHeRuSubcarriers(MHz_u bandWidth,
NS_ASSERT(bandIndex == 0);
bandWidth /= centerFrequencies.size();
}
uint32_t centerFrequencyIndex = 0;
switch (static_cast<uint16_t>(bandWidth))
{
case 20:
centerFrequencyIndex = (nGuardBands / 2) + 6 + 122;
break;
case 40:
centerFrequencyIndex = (nGuardBands / 2) + 12 + 244;
break;
case 80:
centerFrequencyIndex = (nGuardBands / 2) + 12 + 500;
break;
case 160:
centerFrequencyIndex = (nGuardBands / 2) + 12 + 1012;
break;
default:
NS_FATAL_ERROR("ChannelWidth " << bandWidth << " unsupported");
break;
}
// Figures 27-5 to 27-7 of IEEE 802.11ax-2021: the number of guard subcarriers is 6 for 20 MHz
// MHz HE PPDUs and 12 for 40/80/160 MHz HE PPDUs
const uint32_t guardSubcarriers = (bandWidth < MHz_u{40}) ? 6 : 12;
const auto refRu = WifiRu::GetRuType(bandWidth);
const auto mc{WIFI_MOD_CLASS_HE};
const auto offset = WifiRu::GetSubcarrierGroup(bandWidth, refRu, 1, mc).back().second;
uint32_t centerFrequencyIndex = (nGuardBands / 2) + guardSubcarriers + offset;
const auto numBandsInBand = static_cast<size_t>(MHzToHz(bandWidth) / subcarrierSpacing);
centerFrequencyIndex += numBandsInBand * bandIndex;
// start and stop subcarriers might be in different frequency segments, hence define a low and a

8
src/wifi/model/he/he-phy.h
View File

@@ -434,15 +434,15 @@ class HePhy : public VhtPhy
* @param centerFrequencies the center frequency of each segment
* @param totalWidth the width of the operating channel
* @param subcarrierSpacing the subcarrier spacing
* @param subcarrierRange the subcarrier range of the HE RU
* @param subcarrierRange the subcarrier range of the RU
* @param bandIndex the index (starting at 0) of the band within the operating channel
* @return the converted subcarriers
*
* This is a helper function to convert HE RU subcarriers, which are relative to the center
* This is a helper function to convert RU subcarriers, which are relative to the center
* frequency subcarrier, to the indexes used by the Spectrum model. The size of the returned
* vector corresponds to the number of segments covered by the HE RU.
* vector corresponds to the number of segments covered by the RU.
*/
static std::vector<WifiSpectrumBandIndices> ConvertHeRuSubcarriers(
static std::vector<WifiSpectrumBandIndices> ConvertRuSubcarriers(
MHz_u bandWidth,
MHz_u guardBandwidth,
const std::vector<MHz_u>& centerFrequencies,

14
src/wifi/model/spectrum-wifi-phy.cc
View File

@@ -165,13 +165,13 @@ SpectrumWifiPhy::GetRuBands(Ptr<WifiSpectrumPhyInterface> spectrumPhyInterface,
SubcarrierRange subcarrierRange =
std::make_pair(group.front().first, group.back().second);
const auto bandIndices =
HePhy::ConvertHeRuSubcarriers(bw,
guardBandwidth,
spectrumPhyInterface->GetCenterFrequencies(),
spectrumPhyInterface->GetChannelWidth(),
GetSubcarrierSpacing(),
subcarrierRange,
i);
HePhy::ConvertRuSubcarriers(bw,
guardBandwidth,
spectrumPhyInterface->GetCenterFrequencies(),
spectrumPhyInterface->GetChannelWidth(),
GetSubcarrierSpacing(),
subcarrierRange,
i);
WifiSpectrumBandInfo band{};
for (const auto& indicesPerSegment : bandIndices)

16
src/wifi/test/wifi-phy-ofdma-test.cc
View File

@@ -148,14 +148,14 @@ OfdmaTestHePhy::GetNonOfdmaBand(const WifiTxVector& txVector, uint16_t staId) co
WifiRu::GetPhyIndex(nonOfdmaRu,
channelWidth,
m_wifiPhy->GetOperatingChannel().GetPrimaryChannelIndex(MHz_u{20})));
const auto indices = ConvertHeRuSubcarriers(
channelWidth,
GetGuardBandwidth(m_wifiPhy->GetChannelWidth()),
m_wifiPhy->GetOperatingChannel().GetFrequencies(),
m_wifiPhy->GetChannelWidth(),
m_wifiPhy->GetSubcarrierSpacing(),
{groupPreamble.front().first, groupPreamble.back().second},
m_wifiPhy->GetOperatingChannel().GetPrimaryChannelIndex(channelWidth));
const auto indices =
ConvertRuSubcarriers(channelWidth,
GetGuardBandwidth(m_wifiPhy->GetChannelWidth()),
m_wifiPhy->GetOperatingChannel().GetFrequencies(),
m_wifiPhy->GetChannelWidth(),
m_wifiPhy->GetSubcarrierSpacing(),
{groupPreamble.front().first, groupPreamble.back().second},
m_wifiPhy->GetOperatingChannel().GetPrimaryChannelIndex(channelWidth));
WifiSpectrumBandInfo nonOfdmaBand{};
for (const auto& indicesPerSegment : indices)
{