wifi: Clear PSDU map if no immediate response expected with BAR-BA ack sequence

Otherwise, HeFEM::ProtectionCompleted() called upon sending the first
BAR will enter the wrong if branch

RELEASE_NOTES.md

@@ -48,6 +48,7 @@ The required Doxygen version for documentation generation is version 1.11.
 ### Bugs fixed
 
 - (wifi) Retransmit procedures have been aligned with the standard specifications.
+- (wifi) Clear PSDU map if no immediate response expected with BAR-BA ack sequence
 
 ## Release 3.43
 

src/wifi/model/he/he-frame-exchange-manager.cc

@@ -927,9 +927,12 @@ HeFrameExchangeManager::SendPsduMap()
         auto hePhy = StaticCast<HePhy>(m_phy->GetPhyEntity(responseTxVector->GetModulationClass()));
         hePhy->SetTrigVector(m_trigVector, m_txTimer.GetDelayLeft());
     }
-    else if (timerType == WifiTxTimer::NOT_RUNNING && m_txParams.m_txVector.IsUlMu())
+    else if (timerType == WifiTxTimer::NOT_RUNNING &&
+             (m_txParams.m_txVector.IsUlMu() ||
+              m_txParams.m_acknowledgment->method == WifiAcknowledgment::DL_MU_BAR_BA_SEQUENCE))
     {
-        // clear m_psduMap after sending QoS Null frames following a BSRP Trigger Frame
+        // clear m_psduMap after sending QoS Null frames following a BSRP Trigger Frame or after
+        // sending a DL MU PPDU with BAR-BA ack sequence and no immediate response is expected
         Simulator::Schedule(txDuration, &WifiPsduMap::clear, &m_psduMap);
     }