diff --git a/src/wifi/model/spectrum-wifi-phy.cc b/src/wifi/model/spectrum-wifi-phy.cc
index 3b7ebe024..e012e8683 100644
--- a/src/wifi/model/spectrum-wifi-phy.cc
+++ b/src/wifi/model/spectrum-wifi-phy.cc
@@ -28,11 +28,14 @@
 #include "ns3/boolean.h"
 #include "ns3/net-device.h"
 #include "ns3/node.h"
+#include "ns3/simulator.h"
 #include "spectrum-wifi-phy.h"
 #include "wifi-spectrum-phy-interface.h"
 #include "wifi-utils.h"
 #include "wifi-ppdu.h"
 #include "wifi-psdu.h"
+#include "ap-wifi-mac.h"
+#include "wifi-net-device.h"
 
 namespace ns3 {
 
@@ -356,7 +359,26 @@ SpectrumWifiPhy::StartRx (Ptr<SpectrumSignalParameters> rxParams)
 
   NS_LOG_INFO ("Received Wi-Fi signal");
   Ptr<WifiPpdu> ppdu = Copy (wifiRxParams->ppdu);
-  StartReceivePreamble (ppdu, rxPowerW);
+  if (ppdu->GetTxVector ().GetPreambleType () == WIFI_PREAMBLE_HE_TB
+      && wifiRxParams->txPsdFlag == PSD_HE_TB_OFDMA_PORTION
+      && m_currentHeTbPpduUid == ppdu->GetUid ())
+        {
+      Ptr<WifiNetDevice> device = DynamicCast<WifiNetDevice> (GetDevice ());
+      bool isAp = (DynamicCast<ApWifiMac> (device->GetMac ()) != 0);
+      if (isAp)
+        {
+          StartReceiveOfdmaPayload (ppdu, rxPowerW);
+        }
+      else
+        {
+          NS_LOG_INFO ("Ignore UL-OFDMA since device is not AP");
+          m_currentPreambleEvents.clear ();
+        }
+    }
+  else
+    {
+      StartReceivePreamble (ppdu, rxPowerW);
+    }
 }
 
 Ptr<AntennaModel>
@@ -382,7 +404,7 @@ SpectrumWifiPhy::CreateWifiSpectrumPhyInterface (Ptr<NetDevice> device)
 }
 
 Ptr<SpectrumValue>
-SpectrumWifiPhy::GetTxPowerSpectralDensity (double txPowerW, Ptr<WifiPpdu> ppdu)
+SpectrumWifiPhy::GetTxPowerSpectralDensity (double txPowerW, Ptr<WifiPpdu> ppdu, bool isOfdma)
 {
   WifiTxVector txVector = ppdu->GetTxVector ();
   uint16_t centerFrequency = GetCenterFrequencyForChannelWidth (txVector);
@@ -407,7 +429,7 @@ SpectrumWifiPhy::GetTxPowerSpectralDensity (double txPowerW, Ptr<WifiPpdu> ppdu)
                                                                        m_txMaskInnerBandMinimumRejection, m_txMaskOuterBandMinimumRejection, m_txMaskOuterBandMaximumRejection);
       break;
     case WIFI_MOD_CLASS_HE:
-      if (ppdu->IsUlMu ())
+      if (isOfdma)
         {
           WifiSpectrumBand band = GetRuBand (txVector, GetStaId (ppdu));
           v = WifiSpectrumValueHelper::CreateHeMuOfdmTxPowerSpectralDensity (centerFrequency, channelWidth, txPowerW, GetGuardBandwidth (channelWidth), band);
@@ -448,16 +470,64 @@ SpectrumWifiPhy::StartTx (Ptr<WifiPpdu> ppdu)
   double txPowerDbm = GetTxPowerForTransmission (txVector) + GetTxGain ();
   NS_LOG_DEBUG ("Start transmission: signal power before antenna gain=" << txPowerDbm << "dBm");
   double txPowerWatts = DbmToW (txPowerDbm);
-  Ptr<SpectrumValue> txPowerSpectrum = GetTxPowerSpectralDensity (txPowerWatts, ppdu);
-  Ptr<WifiSpectrumSignalParameters> txParams = Create<WifiSpectrumSignalParameters> ();
-  txParams->duration = ppdu->GetTxDuration ();
-  txParams->psd = txPowerSpectrum;
   NS_ASSERT_MSG (m_wifiSpectrumPhyInterface, "SpectrumPhy() is not set; maybe forgot to call CreateWifiSpectrumPhyInterface?");
+  if (txVector.GetPreambleType () == WIFI_PREAMBLE_HE_TB)
+    {
+      //non-OFDMA part
+      Time nonOfdmaDuration = CalculatePhyPreambleAndHeaderDuration (txVector); //consider that HE-STF and HE-LTFs are also part of the non-OFDMA part
+      Ptr<SpectrumValue> txPowerSpectrum = GetTxPowerSpectralDensity (txPowerWatts, ppdu);
+      Ptr<WifiSpectrumSignalParameters> txParams = Create<WifiSpectrumSignalParameters> ();
+      txParams->duration = nonOfdmaDuration;
+      txParams->psd = txPowerSpectrum;
+      txParams->txPhy = m_wifiSpectrumPhyInterface->GetObject<SpectrumPhy> ();
+      txParams->txAntenna = m_antenna;
+      txParams->ppdu = ppdu;
+      txParams->txPsdFlag = PSD_HE_TB_NON_OFDMA_PORTION;
+      NS_LOG_DEBUG ("Starting non-OFDMA transmission with power " << WToDbm (txPowerWatts) << " dBm on channel " << +GetChannelNumber () << " for " << txParams->duration.GetMicroSeconds () << " us");
+      NS_LOG_DEBUG ("Starting non-OFDMA transmission with integrated spectrum power " << WToDbm (Integral (*txPowerSpectrum)) << " dBm; spectrum model Uid: " << txPowerSpectrum->GetSpectrumModel ()->GetUid ());
+      Transmit (txParams);
+
+      //OFDMA part
+      Simulator::Schedule (nonOfdmaDuration, &SpectrumWifiPhy::StartOfdmaTx, this, ppdu, txPowerWatts);
+    }
+  else
+    {
+      Ptr<SpectrumValue> txPowerSpectrum = GetTxPowerSpectralDensity (txPowerWatts, ppdu);
+      Ptr<WifiSpectrumSignalParameters> txParams = Create<WifiSpectrumSignalParameters> ();
+      txParams->duration = ppdu->GetTxDuration ();
+      txParams->psd = txPowerSpectrum;
+      txParams->txPhy = m_wifiSpectrumPhyInterface->GetObject<SpectrumPhy> ();
+      txParams->txAntenna = m_antenna;
+      txParams->ppdu = ppdu;
+      NS_LOG_DEBUG ("Starting transmission with power " << WToDbm (txPowerWatts) << " dBm on channel " << +GetChannelNumber () << " for " << txParams->duration.GetMicroSeconds () << " us");
+      NS_LOG_DEBUG ("Starting transmission with integrated spectrum power " << WToDbm (Integral (*txPowerSpectrum)) << " dBm; spectrum model Uid: " << txPowerSpectrum->GetSpectrumModel ()->GetUid ());
+      Transmit (txParams);
+    }
+}
+
+void
+SpectrumWifiPhy::StartOfdmaTx (Ptr<WifiPpdu> ppdu, double txPowerWatts)
+{
+  NS_LOG_FUNCTION (this << ppdu << txPowerWatts);
+  NS_ASSERT (ppdu->IsUlMu ());
+  Ptr<SpectrumValue> txPowerSpectrum = GetTxPowerSpectralDensity (txPowerWatts, ppdu, true);
+  Ptr<WifiSpectrumSignalParameters> txParams = Create<WifiSpectrumSignalParameters> ();
+  WifiTxVector txVector = ppdu->GetTxVector ();
+  txParams->duration = ppdu->GetTxDuration () - CalculatePhyPreambleAndHeaderDuration (txVector);
+  txParams->psd = txPowerSpectrum;
   txParams->txPhy = m_wifiSpectrumPhyInterface->GetObject<SpectrumPhy> ();
   txParams->txAntenna = m_antenna;
   txParams->ppdu = ppdu;
-  NS_LOG_DEBUG ("Starting transmission with power " << WToDbm (txPowerWatts) << " dBm on channel " << +GetChannelNumber ());
-  NS_LOG_DEBUG ("Starting transmission with integrated spectrum power " << WToDbm (Integral (*txPowerSpectrum)) << " dBm; spectrum model Uid: " << txPowerSpectrum->GetSpectrumModel ()->GetUid ());
+  txParams->txPsdFlag = PSD_HE_TB_OFDMA_PORTION;
+  NS_LOG_DEBUG ("Starting OFDMA transmission with power " << WToDbm (txPowerWatts) << " dBm on channel " << +GetChannelNumber () << " for " << txParams->duration.GetMicroSeconds () << " us");
+  NS_LOG_DEBUG ("Starting OFDMA transmission with integrated spectrum power " << WToDbm (Integral (*txPowerSpectrum)) << " dBm; spectrum model Uid: " << txPowerSpectrum->GetSpectrumModel ()->GetUid ());
+  Transmit (txParams);
+}
+
+void
+SpectrumWifiPhy::Transmit (Ptr<WifiSpectrumSignalParameters> txParams)
+{
+  NS_LOG_FUNCTION (this << txParams);
   m_channel->StartTx (txParams);
 }
 
diff --git a/src/wifi/model/spectrum-wifi-phy.h b/src/wifi/model/spectrum-wifi-phy.h
index b48fcce37..910c20df4 100644
--- a/src/wifi/model/spectrum-wifi-phy.h
+++ b/src/wifi/model/spectrum-wifi-phy.h
@@ -181,12 +181,13 @@ private:
   /**
    * \param txPowerW power in W to spread across the bands
    * \param ppdu the PPDU that will be transmitted
+   * \param isOfdma flag whether the constructed Tx PSD is for the OFDMA part of an HE TB PPDU
    * \return Pointer to SpectrumValue
    *
    * This is a helper function to create the right TX PSD corresponding
    * to the standard in use.
    */
-  Ptr<SpectrumValue> GetTxPowerSpectralDensity (double txPowerW, Ptr<WifiPpdu> ppdu);
+  Ptr<SpectrumValue> GetTxPowerSpectralDensity (double txPowerW, Ptr<WifiPpdu> ppdu, bool isOfdma = false);
 
   /**
    * \param channelWidth the total channel width (MHz) used for the OFDMA transmission
@@ -197,6 +198,21 @@ private:
    */
   WifiSpectrumBand ConvertHeRuSubcarriers (uint16_t channelWidth, HeRu::SubcarrierRange range) const;
 
+  /**
+   * This function is called to send the OFDMA part of a PPDU.
+   *
+   * \param ppdu the PPDU to send
+   * \param txPowerWatts the transmit power in watts
+   */
+  void StartOfdmaTx (Ptr<WifiPpdu> ppdu, double txPowerWatts);
+
+  /**
+   * This function is sending the signal to the Spectrum channel
+   *
+   * \param txParams the parameters to be provided to the Spectrum channel
+   */
+  void Transmit (Ptr<WifiSpectrumSignalParameters> txParams);
+
   /**
    * Perform run-time spectrum model change
    */
diff --git a/src/wifi/model/wifi-phy.cc b/src/wifi/model/wifi-phy.cc
index deddacb30..cb00d7692 100644
--- a/src/wifi/model/wifi-phy.cc
+++ b/src/wifi/model/wifi-phy.cc
@@ -512,6 +512,7 @@ WifiPhy::WifiPhy ()
     m_endPhyRxEvent (),
     m_endTxEvent (),
     m_previouslyRxPpduUid (UINT64_MAX),
+    m_currentHeTbPpduUid (UINT64_MAX),
     m_standard (WIFI_PHY_STANDARD_UNSPECIFIED),
     m_band (WIFI_PHY_BAND_UNSPECIFIED),
     m_isConstructed (false),
@@ -2988,7 +2989,7 @@ WifiPhy::StartReceiveHeader (Ptr<Event> event)
   double snr = snrPer.snr;
   NS_LOG_DEBUG ("snr(dB)=" << RatioToDb (snrPer.snr));
 
-  Time headerPayloadDuration = m_currentEvent->GetDuration () - (Simulator::Now () - m_currentEvent->GetStartTime ()); //startOfPreambleDuration;
+  Time headerPayloadDuration = m_currentEvent->GetStartTime () + m_currentEvent->GetPpdu ()->GetTxDuration () - Simulator::Now ();
 
   if (!m_preambleDetectionModel || (m_preambleDetectionModel->IsPreambleDetected (m_currentEvent->GetRxPowerW (band), snr, m_channelWidth)))
     {
@@ -3150,7 +3151,7 @@ WifiPhy::StartReceivePreamble (Ptr<WifiPpdu> ppdu, RxPowerWattPerChannelBand rxP
       else
         {
           NS_LOG_DEBUG ("Received a new HE TB PPDU for UID " << ppdu->GetUid () << " from STA-ID " << ppdu->GetStaId () << " and BSS color " << +txVector.GetBssColor ());
-          event = m_interference.Add (ppdu, txVector, rxDuration, rxPowersW);
+          event = m_interference.Add (ppdu, txVector, CalculatePhyPreambleAndHeaderDuration (txVector), rxPowersW); //the OFDMA part of the transmission will be added later on
           m_currentPreambleEvents.insert ({std::make_pair (ppdu->GetUid (), ppdu->GetPreamble ()), event});
         }
     }
@@ -3293,6 +3294,24 @@ WifiPhy::MaybeCcaBusyDuration ()
     }
 }
 
+void
+WifiPhy::StartReceiveOfdmaPayload (Ptr<WifiPpdu> ppdu, RxPowerWattPerChannelBand rxPowersW)
+{
+  //The total RX power corresponds to the maximum over all the bands
+  auto it = std::max_element (rxPowersW.begin (), rxPowersW.end (),
+    [] (const std::pair<WifiSpectrumBand, double>& p1, const std::pair<WifiSpectrumBand, double>& p2) {
+      return p1.second < p2.second;
+    });
+  NS_LOG_FUNCTION (this << *ppdu << it->second);
+
+  WifiTxVector txVector = ppdu->GetTxVector ();
+  Time payloadDuration = ppdu->GetTxDuration () - CalculatePhyPreambleAndHeaderDuration (txVector);
+  Ptr<Event> event = m_interference.Add (ppdu, txVector, payloadDuration, rxPowersW);
+
+  NS_ASSERT (m_endRxEvent.IsExpired ());
+  m_endRxEvent = Simulator::Schedule (payloadDuration, &WifiPhy::EndReceive, this, event);
+}
+
 void
 WifiPhy::StartReceivePayload (Ptr<Event> event)
 {
@@ -3317,7 +3336,7 @@ WifiPhy::StartReceivePayload (Ptr<Event> event)
       canReceivePayload = true;
     }
   WifiTxVector txVector = event->GetTxVector ();
-  Time payloadDuration = event->GetEndTime () - event->GetStartTime () - CalculatePhyPreambleAndHeaderDuration (txVector);
+  Time payloadDuration = ppdu->GetTxDuration () - CalculatePhyPreambleAndHeaderDuration (txVector);
   bool success = false;
   if (canReceivePayload) //PHY reception succeeded
     {
@@ -3357,9 +3376,17 @@ WifiPhy::StartReceivePayload (Ptr<Event> event)
                 }
               m_state->SwitchToRx (payloadDuration);
               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
-              m_endRxEvent = Simulator::Schedule (payloadDuration, &WifiPhy::EndReceive, this, event);
               success = true;
               NS_LOG_DEBUG ("Receiving PSDU");
+              if (txVector.GetPreambleType () == WIFI_PREAMBLE_HE_TB)
+                {
+                  m_currentHeTbPpduUid = ppdu->GetUid ();
+                  //EndReceive is scheduled by StartReceiveOfdmaPayload
+                }
+              else
+                {
+                  m_endRxEvent = Simulator::Schedule (payloadDuration, &WifiPhy::EndReceive, this, event);
+                }
             }
           else //mode is not allowed
             {
diff --git a/src/wifi/model/wifi-phy.h b/src/wifi/model/wifi-phy.h
index 7a5120ac9..45c7569ed 100644
--- a/src/wifi/model/wifi-phy.h
+++ b/src/wifi/model/wifi-phy.h
@@ -211,7 +211,7 @@ public:
    * Start receiving the PHY preamble of a PPDU (i.e. the first bit of the preamble has arrived).
    *
    * \param ppdu the arriving PPDU
-   * \param rxPowersW the receive power in W per 20 MHz channel band
+   * \param rxPowersW the receive power in W per band
    */
   void StartReceivePreamble (Ptr<WifiPpdu> ppdu, RxPowerWattPerChannelBand rxPowersW);
 
@@ -236,6 +236,15 @@ public:
    */
   void StartReceivePayload (Ptr<Event> event);
 
+  /**
+   * Start receiving the PSDU (i.e. the first symbol of the PSDU has arrived) of an UL-OFDMA transmission.
+   * This function is called upon the RX event corresponding to the OFDMA part of the UL MU PPDU.
+   *
+   * \param ppdu the arriving PPDU
+   * \param rxPowersW the receive power in W per band
+   */
+  void StartReceiveOfdmaPayload (Ptr<WifiPpdu> ppdu, RxPowerWattPerChannelBand rxPowersW);
+
   /**
    * The last symbol of the PPDU has arrived.
    *
@@ -1864,6 +1873,8 @@ protected:
 
   uint64_t m_previouslyRxPpduUid;      //!< UID of the previously received PPDU (reused by HE TB PPDUs), reset to UINT64_MAX upon transmission
 
+  uint64_t m_currentHeTbPpduUid;       //!< UID of the HE TB PPDU being received
+
   static uint64_t m_globalPpduUid;     //!< Global counter of the PPDU UID