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wifi: Main PHY must have enough time to switch when aux PHY receives an ICF

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This commit is contained in:
Stefano Avallone
2024-01-31 16:35:17 +01:00
parent fc4df268bd
commit bbf1086821
2 changed files with 24 additions and 19 deletions
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37
src/wifi/model/eht/eht-frame-exchange-manager.cc
View File

@@ -972,16 +972,11 @@ EhtFrameExchangeManager::ReceiveMpdu(Ptr<const WifiMpdu> mpdu,
}
/**
* It might happen that the AP MLD has not yet received a data frame being transmitted
* by us on another link and starts sending an ICF on this link. The transmission of
* the ICF might be long enough to terminate after the subsequent acknowledgment, which
* terminates the TXOP on the other link. Consequently, no TXOP is ongoing when the
* reception of the ICF ends, hence the ICF is not dropped and a DL TXOP can start on
* this link. However, even if the aux PHY is able to receive the ICF, we need to allow
* enough time for the main PHY to switch to this link. Therefore, we assume that the
* ICF is successfully received (by an aux PHY) if the TXOP on the other link ended
* before the padding of the ICF. In order to determine when the TXOP ended, we can
* determine when the medium sync delay timer started on this link.
* It might happen that, while the aux PHY is receiving an ICF, the main PHY is
* completing a TXOP on another link or is returning to the primary link after a TXOP
* is completed on another link. In order to respond to the ICF, it is necessary that
* the main PHY has enough time to switch and be ready to operate on this link by the
* end of the ICF padding.
*
* TXOP end
* │
@@ -991,28 +986,32 @@ EhtFrameExchangeManager::ReceiveMpdu(Ptr<const WifiMpdu> mpdu,
* EMLSR │ QoS │ │ main PHY
* client │ Data │ │
* └─────────┘ │
* │- medium sync delay timer -│
* ┌─────┬───┐ this
* AP MLD │ ICF │pad│ link
* ────────────────────┴─────┴───┴───────────────────────────────────
* aux PHY
*/
if (auto elapsed =
m_staMac->GetEmlsrManager()->GetElapsedMediumSyncDelayTimer(m_linkId))
{
TimeValue padding;
m_staMac->GetEmlsrManager()->GetAttribute("EmlsrPaddingDelay", padding);
auto emlsrManager = m_staMac->GetEmlsrManager();
NS_ASSERT(emlsrManager);
if (*elapsed < padding.Get())
if (auto mainPhy = m_staMac->GetDevice()->GetPhy(emlsrManager->GetMainPhyId());
mainPhy != m_phy)
{
const auto delay = mainPhy->GetChannelSwitchDelay();
if (mainPhy->GetState()->GetLastTime({WifiPhyState::TX,
// WifiPhyState::RX, comment out for now
WifiPhyState::SWITCHING,
WifiPhyState::SLEEP}) >
Simulator::Now() - delay)
{
NS_LOG_DEBUG("Drop ICF due to not enough time for the main PHY to switch link");
return;
}
}
NS_ASSERT(m_staMac->GetEmlsrManager());
m_staMac->GetEmlsrManager()->NotifyIcfReceived(m_linkId);
emlsrManager->NotifyIcfReceived(m_linkId);
icfReceived = true;
// we just got involved in a DL TXOP. Check if we are still involved in the TXOP in a

6
src/wifi/test/wifi-emlsr-test.cc
View File

@@ -795,6 +795,12 @@ EmlsrDlTxopTest::Transmit(Ptr<WifiMac> mac,
void
EmlsrDlTxopTest::DoSetup()
{
// Channel switch delay should be less than the ICF padding duration, otherwise
// DL TXOPs cannot be initiated on non-primary links
auto delay = std::min(MicroSeconds(100),
*std::min_element(m_paddingDelay.cbegin(), m_paddingDelay.cend()));
Config::SetDefault("ns3::WifiPhy::ChannelSwitchDelay", TimeValue(MicroSeconds(75)));
EmlsrOperationsTestBase::DoSetup();
m_errorModel = CreateObject<ListErrorModel>();