F5/unison
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

wifi: Rework PSD creation to support channels widths made of multiple 80 MHz ones

Browse Source
This commit is contained in:
Sébastien Deronne
2024-11-09 12:41:54 +01:00
parent 80e0e09584
commit 4abcc794e5
2 changed files with 49 additions and 65 deletions
Download Patch File Download Diff File Expand all files Collapse all files

103
src/wifi/model/wifi-spectrum-value-helper.cc
View File

@@ -489,6 +489,9 @@ WifiSpectrumValueHelper::CreateHeOfdmTxPowerSpectralDensity(
NS_ASSERT_MSG(
centerFrequencies.size() == 1 || channelWidth == MHz_u{160},
"PSD for non-contiguous channels is only possible when the total width is 160 MHz");
NS_ASSERT_MSG(
(channelWidth != 160) || (centerFrequencies.size() <= 2),
"It is not possible to create a PSD made of more than 2 segments for a width of 160 MHz");
NS_LOG_FUNCTION(printFrequencies(centerFrequencies)
<< channelWidth << txPower << guardBandwidth << minInnerBand << minOuterBand
<< lowestPoint);
@@ -511,14 +514,6 @@ WifiSpectrumValueHelper::CreateHeOfdmTxPowerSpectralDensity(
(nAllocatedBands + nGuardBands + nUnallocatedBands + 1),
"Unexpected number of bands " << c->GetSpectrumModel()->GetNumBands());
Watt_u txPowerPerBand{0.0};
uint32_t start1;
uint32_t stop1;
uint32_t start2;
uint32_t stop2;
uint32_t start3;
uint32_t stop3;
uint32_t start4;
uint32_t stop4;
// Prepare spectrum mask specific variables
auto innerSlopeWidth =
static_cast<uint32_t>((MHzToHz(MHz_u{1}) / carrierSpacing) +
@@ -526,6 +521,9 @@ WifiSpectrumValueHelper::CreateHeOfdmTxPowerSpectralDensity(
std::vector<std::vector<WifiSpectrumBandIndices>> subBandsPerSegment(
centerFrequencies.size()); // list of data/pilot-containing subBands (sent at 0dBr)
WifiSpectrumBandIndices maskBand(0, nAllocatedBands + nGuardBands + nUnallocatedBands);
std::size_t skippedSubbands{0};
std::size_t numAllocatedSubbands{0};
std::size_t numDc{0};
switch (static_cast<uint16_t>(channelWidth))
{
case 20:
@@ -533,75 +531,62 @@ WifiSpectrumValueHelper::CreateHeOfdmTxPowerSpectralDensity(
txPowerPerBand = txPower / 242;
innerSlopeWidth = static_cast<uint32_t>((Hz_u{5e5} / carrierSpacing) +
0.5); // [-10.25;-9.75] & [9.75;10.25]
// skip the guard band and 6 subbands, then place power in 121 subbands, then
// skip 3 DC, then place power in 121 subbands, then skip
// the final 5 subbands and the guard band.
start1 = (nGuardBands / 2) + 6;
stop1 = start1 + 121 - 1;
start2 = stop1 + 4;
stop2 = start2 + 121 - 1;
subBandsPerSegment.at(0).emplace_back(start1, stop1);
subBandsPerSegment.at(0).emplace_back(start2, stop2);
skippedSubbands = 6;
numAllocatedSubbands = 121;
numDc = 3;
break;
case 40:
// 484 subcarriers (468 data + 16 pilot)
txPowerPerBand = txPower / 484;
// skip the guard band and 12 subbands, then place power in 242 subbands, then
// skip 5 DC, then place power in 242 subbands, then skip
// the final 11 subbands and the guard band.
start1 = (nGuardBands / 2) + 12;
stop1 = start1 + 242 - 1;
start2 = stop1 + 6;
stop2 = start2 + 242 - 1;
subBandsPerSegment.at(0).emplace_back(start1, stop1);
subBandsPerSegment.at(0).emplace_back(start2, stop2);
skippedSubbands = 12;
numAllocatedSubbands = 242;
numDc = 5;
break;
case 80:
// 996 subcarriers (980 data + 16 pilot)
txPowerPerBand = txPower / 996;
// skip the guard band and 12 subbands, then place power in 498 subbands, then
// skip 5 DC, then place power in 498 subbands, then skip
// the final 11 subbands and the guard band.
start1 = (nGuardBands / 2) + 12;
stop1 = start1 + 498 - 1;
start2 = stop1 + 6;
stop2 = start2 + 498 - 1;
subBandsPerSegment.at(0).emplace_back(start1, stop1);
subBandsPerSegment.at(0).emplace_back(start2, stop2);
case 160: // 2 x 80 MHz
case 320: // 4 x 80 MHz
// 996 subcarriers (980 data + 16 pilot) per 80 MHz band
txPowerPerBand = txPower / (996 * (channelWidth / 80));
skippedSubbands = 12;
numAllocatedSubbands = 498;
numDc = 5;
break;
case 160: {
NS_ASSERT_MSG(centerFrequencies.size() <= 2,
"It is not possible to create a PSD made of more than 2 segments for a width "
"of 160 MHz");
// 2 x 996 subcarriers (2 x 80 MHZ bands)
txPowerPerBand = txPower / (2 * 996);
start1 = (nGuardBands / 2) + 12;
stop1 = start1 + 498 - 1;
start2 = stop1 + 6;
stop2 = start2 + 498 - 1;
start3 = stop2 + (2 * 12) + nUnallocatedBands;
stop3 = start3 + 498 - 1;
start4 = stop3 + 6;
stop4 = start4 + 498 - 1;
subBandsPerSegment.at(0).emplace_back(start1, stop1);
subBandsPerSegment.at(0).emplace_back(start2, stop2);
subBandsPerSegment.at(subBandsPerSegment.size() - 1).emplace_back(start3, stop3);
subBandsPerSegment.at(subBandsPerSegment.size() - 1).emplace_back(start4, stop4);
break;
}
default:
NS_FATAL_ERROR("ChannelWidth " << channelWidth << " unsupported");
break;
}
// skip the guard band and skipped subbands, then place power in allocated subbands, then skip
// DC subbands, then place power in allocated subbands, then skip the final 11 subbands and the
// guard band.
auto start = (nGuardBands / 2) + skippedSubbands;
auto stop = start + numAllocatedSubbands - 1;
subBandsPerSegment.at(0).emplace_back(start, stop);
start = stop + numDc + 1;
stop = start + numAllocatedSubbands - 1;
subBandsPerSegment.at(0).emplace_back(start, stop);
if (channelWidth >= 160)
{
for (std::size_t i = 1; i < (channelWidth / 80); ++i)
{
start = subBandsPerSegment.front().back().second + (2 * skippedSubbands) +
nUnallocatedBands;
auto stop = start + numAllocatedSubbands - 1;
subBandsPerSegment.back().emplace_back(start, stop);
start = stop + numDc + 1;
stop = start + numAllocatedSubbands - 1;
subBandsPerSegment.back().emplace_back(start, stop);
}
}
// Create punctured bands
auto puncturedSlopeWidth =
static_cast<uint32_t>((Hz_u{500e3} / carrierSpacing) +
0.5); // size in number of subcarriers of the punctured slope band
std::vector<std::vector<WifiSpectrumBandIndices>> puncturedBandsPerSegment;
std::size_t subcarriersPerSuband = (MHzToHz(MHz_u{20}) / carrierSpacing);
uint32_t start = (nGuardBands / 2);
uint32_t stop = start + subcarriersPerSuband - 1;
start = (nGuardBands / 2);
stop = start + subcarriersPerSuband - 1;
if (!puncturedSubchannels.empty())
{
for (std::size_t i = 0; i < subBandsPerSegment.size(); ++i)

11
src/wifi/model/wifi-spectrum-value-helper.h
View File

@@ -125,9 +125,8 @@ class WifiSpectrumValueHelper
const std::vector<bool>& puncturedSubchannels = {});
/**
* Create a transmit power spectral density corresponding to OFDM
* High Throughput (HT) (802.11n/ac). Channel width may vary between
* 20, 40, 80, and 160 MHz.
* Create a transmit power spectral density corresponding to OFDM High Throughput (HT/VHT)
* (802.11n/ac). Channel width may vary between 20, 40, 80, and 160 MHz.
*
* @param centerFrequencies center frequency per segment
* @param channelWidth total allocated channel width over all segments
@@ -149,9 +148,9 @@ class WifiSpectrumValueHelper
dBr_u lowestPoint = dBr_u{-40});
/**
* Create a transmit power spectral density corresponding to OFDM
* High Efficiency (HE) (802.11ax) for contiguous channels.
* Channel width may vary between 20, 40, 80, and 160 MHz.
* Create a transmit power spectral density corresponding to OFDM High Efficiency (HE/EHT)
* (802.11ax/be) for contiguous channels. Channel width may vary between 20, 40, 80, 160 and 320
* MHz.
*
* @param centerFrequency center frequency
* @param channelWidth channel width