diff --git a/src/wifi/model/wifi-phy-state-helper.cc b/src/wifi/model/wifi-phy-state-helper.cc
index c08903fbd..3bab853af 100644
--- a/src/wifi/model/wifi-phy-state-helper.cc
+++ b/src/wifi/model/wifi-phy-state-helper.cc
@@ -354,11 +354,13 @@ WifiPhyStateHelper::LogPreviousIdleAndCcaBusyStates (void)
 }
 
 void
-WifiPhyStateHelper::SwitchToTx (Time txDuration, Ptr<const Packet> packet, double txPowerDbm,
-                                WifiTxVector txVector)
+WifiPhyStateHelper::SwitchToTx (Time txDuration, WifiConstPsduMap psdus, double txPowerDbm, WifiTxVector txVector)
 {
-  NS_LOG_FUNCTION (this << txDuration << packet << txPowerDbm << txVector);
-  m_txTrace (packet, txVector.GetMode (), txVector.GetPreambleType (), txVector.GetTxPowerLevel ());
+  NS_LOG_FUNCTION (this << txDuration << psdus << txPowerDbm << txVector);
+  for (auto const& psdu : psdus)
+    {
+      m_txTrace (psdu.second->GetPacket (), txVector.GetMode (), txVector.GetPreambleType (), txVector.GetTxPowerLevel ());
+    }
   Time now = Simulator::Now ();
   switch (GetState ())
     {
diff --git a/src/wifi/model/wifi-phy-state-helper.h b/src/wifi/model/wifi-phy-state-helper.h
index 9474caff6..142d0cf95 100644
--- a/src/wifi/model/wifi-phy-state-helper.h
+++ b/src/wifi/model/wifi-phy-state-helper.h
@@ -27,6 +27,7 @@
 #include "ns3/nstime.h"
 #include "wifi-phy-state.h"
 #include "wifi-preamble.h"
+#include "wifi-ppdu.h"
 
 namespace ns3 {
 
@@ -164,12 +165,12 @@ public:
   /**
    * Switch state to TX for the given duration.
    *
-   * \param txDuration the duration of the TX
-   * \param packet the packet
+   * \param txDuration the duration of the PPDU to transmit
+   * \param psdus the PSDUs in the transmitted PPDU (only one unless it is a MU PPDU)
    * \param txPowerDbm the nominal TX power in dBm
-   * \param txVector the TX vector of the packet
+   * \param txVector the TX vector for the transmission
    */
-  void SwitchToTx (Time txDuration, Ptr<const Packet> packet, double txPowerDbm, WifiTxVector txVector);
+  void SwitchToTx (Time txDuration, WifiConstPsduMap psdus, double txPowerDbm, WifiTxVector txVector);
   /**
    * Switch state to RX for the given duration.
    *
diff --git a/src/wifi/model/wifi-phy.cc b/src/wifi/model/wifi-phy.cc
index e5d7f2e5a..516d406c3 100644
--- a/src/wifi/model/wifi-phy.cc
+++ b/src/wifi/model/wifi-phy.cc
@@ -2570,20 +2570,26 @@ WifiPhy::CalculateTxDuration (WifiConstPsduMap psduMap, WifiTxVector txVector, W
 }
 
 void
-WifiPhy::NotifyTxBegin (Ptr<const WifiPsdu> psdu, double txPowerW)
+WifiPhy::NotifyTxBegin (WifiConstPsduMap psdus, double txPowerW)
 {
-  for (auto& mpdu : *PeekPointer (psdu))
+  for (auto const& psdu : psdus)
     {
-      m_phyTxBeginTrace (mpdu->GetProtocolDataUnit (), txPowerW);
+      for (auto& mpdu : *PeekPointer (psdu.second))
+        {
+          m_phyTxBeginTrace (mpdu->GetProtocolDataUnit (), txPowerW);
+        }
     }
 }
 
 void
-WifiPhy::NotifyTxEnd (Ptr<const WifiPsdu> psdu)
+WifiPhy::NotifyTxEnd (WifiConstPsduMap psdus)
 {
-  for (auto& mpdu : *PeekPointer (psdu))
+  for (auto const& psdu : psdus)
     {
-      m_phyTxEndTrace (mpdu->GetProtocolDataUnit ());
+      for (auto& mpdu : *PeekPointer (psdu.second))
+        {
+          m_phyTxEndTrace (mpdu->GetProtocolDataUnit ());
+        }
     }
 }
 
@@ -2599,27 +2605,36 @@ WifiPhy::NotifyTxDrop (Ptr<const WifiPsdu> psdu)
 void
 WifiPhy::NotifyRxBegin (Ptr<const WifiPsdu> psdu)
 {
-  for (auto& mpdu : *PeekPointer (psdu))
+  if (psdu)
     {
-      m_phyRxBeginTrace (mpdu->GetProtocolDataUnit ());
+      for (auto& mpdu : *PeekPointer (psdu))
+        {
+          m_phyRxBeginTrace (mpdu->GetProtocolDataUnit ());
+        }
     }
 }
 
 void
 WifiPhy::NotifyRxEnd (Ptr<const WifiPsdu> psdu)
 {
-  for (auto& mpdu : *PeekPointer (psdu))
+  if (psdu)
     {
-      m_phyRxEndTrace (mpdu->GetProtocolDataUnit ());
+      for (auto& mpdu : *PeekPointer (psdu))
+        {
+          m_phyRxEndTrace (mpdu->GetProtocolDataUnit ());
+        }
     }
 }
 
 void
 WifiPhy::NotifyRxDrop (Ptr<const WifiPsdu> psdu, WifiPhyRxfailureReason reason)
 {
-  for (auto& mpdu : *PeekPointer (psdu))
+  if (psdu)
     {
-      m_phyRxDropTrace (mpdu->GetProtocolDataUnit (), reason);
+      for (auto& mpdu : *PeekPointer (psdu))
+        {
+          m_phyRxDropTrace (mpdu->GetProtocolDataUnit (), reason);
+        }
     }
 }
 
@@ -2635,7 +2650,7 @@ WifiPhy::NotifyMonitorSniffRx (Ptr<const WifiPsdu> psdu, uint16_t channelFreqMhz
       aMpdu.mpduRefNumber = ++m_rxMpduReferenceNumber;
       size_t nMpdus = psdu->GetNMpdus ();
       NS_ASSERT_MSG (statusPerMpdu.size () == nMpdus, "Should have one reception status per MPDU");
-      aMpdu.type = (psdu->IsSingle ()) ? SINGLE_MPDU: FIRST_MPDU_IN_AGGREGATE;
+      aMpdu.type = (psdu->IsSingle ()) ? SINGLE_MPDU : FIRST_MPDU_IN_AGGREGATE;
       for (size_t i = 0; i < nMpdus;)
         {
           if (statusPerMpdu.at (i)) //packet received without error, hand over to sniffer
@@ -2689,6 +2704,15 @@ void
 WifiPhy::Send (Ptr<const WifiPsdu> psdu, WifiTxVector txVector)
 {
   NS_LOG_FUNCTION (this << *psdu << txVector);
+  WifiConstPsduMap psdus;
+  psdus.insert (std::make_pair (SU_STA_ID, psdu));
+  Send (psdus, txVector);
+}
+
+void
+WifiPhy::Send (WifiConstPsduMap psdus, WifiTxVector txVector)
+{
+  NS_LOG_FUNCTION (this << psdus << txVector);
   /* Transmission can happen if:
    *  - we are syncing on a packet. It is the responsibility of the
    *    MAC layer to avoid doing this but the PHY does nothing to
@@ -2706,11 +2730,14 @@ WifiPhy::Send (Ptr<const WifiPsdu> psdu, WifiTxVector txVector)
   if (m_state->IsStateSleep ())
     {
       NS_LOG_DEBUG ("Dropping packet because in sleep mode");
-      NotifyTxDrop (psdu);
+      for (auto const& psdu : psdus)
+        {
+          NotifyTxDrop (psdu.second);
+        }
       return;
     }
 
-  Time txDuration = CalculateTxDuration (psdu->GetSize (), txVector, GetPhyBand ());
+  Time txDuration = CalculateTxDuration (psdus.at (SU_STA_ID)->GetSize (), txVector, GetPhyBand ()); //TODO: extend CalculateTxDuration for MU
   NS_ASSERT (txDuration.IsStrictlyPositive ());
 
   if ((m_currentEvent != 0) && (m_currentEvent->GetEndTime () > (Simulator::Now () + m_state->GetDelayUntilIdle ())))
@@ -2740,19 +2767,19 @@ WifiPhy::Send (Ptr<const WifiPsdu> psdu, WifiTxVector txVector)
     }
 
   double txPowerW = DbmToW (GetTxPowerForTransmission (txVector) + GetTxGain ());
-  NotifyTxBegin (psdu, txPowerW);
-  m_phyTxPsduBeginTrace (psdu, txVector, txPowerW);
-  NotifyMonitorSniffTx (psdu, GetFrequency (), txVector);
-  m_state->SwitchToTx (txDuration, psdu->GetPacket (), GetPowerDbm (txVector.GetTxPowerLevel ()), txVector);
+  NotifyTxBegin (psdus, txPowerW);
+  m_phyTxPsduBeginTrace (psdus.at (SU_STA_ID), txVector, txPowerW); // TODO: fix for MU
+  NotifyMonitorSniffTx (psdus.at (SU_STA_ID), GetFrequency (), txVector); //TODO: fix for MU
+  m_state->SwitchToTx (txDuration, psdus, GetPowerDbm (txVector.GetTxPowerLevel ()), txVector);
 
-  Ptr<WifiPpdu> ppdu = Create<WifiPpdu> (psdu, txVector, txDuration, GetPhyBand ());
+  Ptr<WifiPpdu> ppdu = Create<WifiPpdu> (psdus, txVector, txDuration, GetPhyBand ());
 
   if (m_wifiRadioEnergyModel != 0 && m_wifiRadioEnergyModel->GetMaximumTimeInState (WifiPhyState::TX) < txDuration)
     {
       ppdu->SetTruncatedTx ();
     }
 
-  m_endTxEvent = Simulator::Schedule (txDuration, &WifiPhy::NotifyTxEnd, this, psdu);
+  m_endTxEvent = Simulator::Schedule (txDuration, &WifiPhy::NotifyTxEnd, this, psdus); //TODO: fix for MU
 
   StartTx (ppdu);
 
@@ -3054,9 +3081,20 @@ WifiPhy::StartReceivePayload (Ptr<Event> event)
               ScheduleEndOfMpdus (event);
             }
           m_state->SwitchToRx (payloadDuration);
-          m_endRxEvent = Simulator::Schedule (payloadDuration, &WifiPhy::EndReceive, this, event);
-          NS_LOG_DEBUG ("Receiving PSDU");
           m_phyRxPayloadBeginTrace (txVector, payloadDuration); //this callback (equivalent to PHY-RXSTART primitive) is triggered only if headers have been correctly decoded and that the mode within is supported
+          Ptr<const WifiPpdu> ppdu = event->GetPpdu ();
+          Ptr<const WifiPsdu> psdu = GetAddressedPsduInPpdu (ppdu);
+          if (psdu)
+            {
+              m_endRxEvent = Simulator::Schedule (payloadDuration, &WifiPhy::EndReceive, this, event);
+              NS_LOG_DEBUG ("Receiving PSDU");
+            }
+          else
+            {
+              NS_ASSERT (ppdu->IsMu ());
+              m_endRxEvent = Simulator::Schedule (payloadDuration, &WifiPhy::ResetReceive, this, event);
+              NS_LOG_DEBUG ("Receiving MU PPDU without any PSDU for this STA");
+            }
           if (txMode.GetModulationClass () == WIFI_MOD_CLASS_HE)
             {
               HePreambleParameters params;
@@ -4589,7 +4627,7 @@ WifiPhy::GetAddressedPsduInPpdu (Ptr<const WifiPpdu> ppdu) const
               bssColor = bssColorAttribute.Get ();
             }
         }
-      uint16_t staId = SU_STA_ID;
+      uint16_t staId = GetStaId ();
       psdu = ppdu->GetPsdu (bssColor, staId);
     }
     return psdu;
diff --git a/src/wifi/model/wifi-phy.h b/src/wifi/model/wifi-phy.h
index ecd7580cd..ee71c6b7d 100644
--- a/src/wifi/model/wifi-phy.h
+++ b/src/wifi/model/wifi-phy.h
@@ -244,6 +244,13 @@ public:
    *        power is calculated as txPowerMin + txPowerLevel * (txPowerMax - txPowerMin) / nTxLevels
    */
   void Send (Ptr<const WifiPsdu> psdu, WifiTxVector txVector);
+  /**
+   * \param psdus the PSDUs to send
+   * \param txVector the TXVECTOR that has tx parameters such as mode, the transmission mode to use to send
+   *        this PSDU, and txPowerLevel, a power level to use to send the whole PPDU. The real transmission
+   *        power is calculated as txPowerMin + txPowerLevel * (txPowerMax - txPowerMin) / nTxLevels
+   */
+  void Send (WifiConstPsduMap psdus, WifiTxVector txVector);
 
   /**
    * \param ppdu the PPDU to send
@@ -1288,17 +1295,17 @@ public:
    * Public method used to fire a PhyTxBegin trace.
    * Implemented for encapsulation purposes.
    *
-   * \param psdu the PSDU being transmitted
+   * \param psdus the PSDUs being transmitted (only one unless DL MU transmission)
    * \param txPowerW the transmit power in Watts
    */
-  void NotifyTxBegin (Ptr<const WifiPsdu> psdu, double txPowerW);
+  void NotifyTxBegin (WifiConstPsduMap psdus, double txPowerW);
   /**
    * Public method used to fire a PhyTxEnd trace.
    * Implemented for encapsulation purposes.
    *
-   * \param psdu the PSDU being transmitted
+   * \param psdus the PSDUs being transmitted (only one unless DL MU transmission)
    */
-  void NotifyTxEnd (Ptr<const WifiPsdu> psdu);
+  void NotifyTxEnd (WifiConstPsduMap psdus);
   /**
    * Public method used to fire a PhyTxDrop trace.
    * Implemented for encapsulation purposes.
diff --git a/src/wifi/model/wifi-ppdu.cc b/src/wifi/model/wifi-ppdu.cc
index 89c34b751..aaa56c39f 100644
--- a/src/wifi/model/wifi-ppdu.cc
+++ b/src/wifi/model/wifi-ppdu.cc
@@ -37,6 +37,7 @@ WifiPpdu::WifiPpdu (Ptr<const WifiPsdu> psdu, WifiTxVector txVector, Time ppduDu
     m_channelWidth (txVector.GetChannelWidth ()),
     m_txPowerLevel (txVector.GetTxPowerLevel ())
 {
+  NS_LOG_FUNCTION (this << *psdu << txVector << ppduDuration << band);
   m_psdus.insert (std::make_pair (SU_STA_ID, psdu));
   SetPhyHeaders (txVector, ppduDuration, band);
 }
@@ -49,6 +50,7 @@ WifiPpdu::WifiPpdu (const WifiConstPsduMap & psdus, WifiTxVector txVector, Time
     m_band (band),
     m_channelWidth (txVector.GetChannelWidth ())
 {
+  NS_LOG_FUNCTION (this << psdus << txVector << ppduDuration << band);
   SetPhyHeaders (txVector, ppduDuration, band);
 }
 
@@ -473,10 +475,7 @@ WifiPpdu::Print (std::ostream& os) const
   os << "preamble=" << m_preamble
      << ", modulation=" << m_modulation
      << ", truncatedTx=" << (m_truncatedTx ? "Y" : "N");
-  for (auto const& psdu : m_psdus)
-    {
-      os << ", PSDU=" << psdu.second;
-    }
+  IsMu () ? (os << ", " << m_psdus) : (os << ", PSDU=" << m_psdus.at (SU_STA_ID));
 }
 
 std::ostream & operator << (std::ostream &os, const WifiPpdu &ppdu)
@@ -485,4 +484,14 @@ std::ostream & operator << (std::ostream &os, const WifiPpdu &ppdu)
   return os;
 }
 
+std::ostream & operator << (std::ostream &os, const WifiConstPsduMap &psdus)
+{
+  for (auto const& psdu : psdus)
+    {
+      os << "PSDU for STA_ID=" << psdu.first
+         << " (" << *psdu.second << ") ";
+    }
+  return os;
+}
+
 } //namespace ns3
diff --git a/src/wifi/model/wifi-ppdu.h b/src/wifi/model/wifi-ppdu.h
index 22beedd97..a922e7989 100644
--- a/src/wifi/model/wifi-ppdu.h
+++ b/src/wifi/model/wifi-ppdu.h
@@ -148,6 +148,15 @@ private:
  */
 std::ostream& operator<< (std::ostream& os, const WifiPpdu &ppdu);
 
+/**
+ * \brief Stream insertion operator.
+ *
+ * \param os the stream
+ * \param psdus the PSDUs
+ * \returns a reference to the stream
+ */
+std::ostream & operator << (std::ostream &os, const WifiConstPsduMap &psdus);
+
 } //namespace ns3
 
 #endif /* WIFI_PPDU_H */