diff --git a/src/wifi/model/he/he-phy.cc b/src/wifi/model/he/he-phy.cc
index 515f207b3..49b274468 100644
--- a/src/wifi/model/he/he-phy.cc
+++ b/src/wifi/model/he/he-phy.cc
@@ -1378,17 +1378,13 @@ HePhy::StartTx(Ptr<const WifiPpdu> ppdu, const WifiTxVector& txVector)
         Transmit(nonOfdmaDuration, ppdu, txVector, "non-OFDMA transmission");
 
         // OFDMA part
-        auto hePpdu = DynamicCast<HePpdu>(ppdu->Copy()); // since flag will be modified
-        NS_ASSERT(hePpdu);
-        hePpdu->SetTxPsdFlag(HePpdu::PSD_HE_PORTION);
         Time ofdmaDuration = ppdu->GetTxDuration() - nonOfdmaDuration;
         Simulator::Schedule(nonOfdmaDuration,
-                            &PhyEntity::Transmit,
+                            &HePhy::StartTxOfdma,
                             this,
-                            ofdmaDuration,
-                            hePpdu,
+                            ppdu,
                             txVector,
-                            "OFDMA transmission");
+                            ofdmaDuration);
     }
     else
     {
@@ -1396,6 +1392,15 @@ HePhy::StartTx(Ptr<const WifiPpdu> ppdu, const WifiTxVector& txVector)
     }
 }
 
+void
+HePhy::StartTxOfdma(Ptr<const WifiPpdu> ppdu, const WifiTxVector& txVector, Time ofdmaDuration)
+{
+    auto hePpdu = DynamicCast<const HePpdu>(ppdu);
+    NS_ASSERT(hePpdu);
+    hePpdu->SetTxPsdFlag(HePpdu::PSD_HE_PORTION);
+    Transmit(ofdmaDuration, ppdu, txVector, "OFDMA transmission");
+}
+
 Time
 HePhy::CalculateTxDuration(WifiConstPsduMap psduMap,
                            const WifiTxVector& txVector,
diff --git a/src/wifi/model/he/he-phy.h b/src/wifi/model/he/he-phy.h
index 68dbd11c4..5c38bc927 100644
--- a/src/wifi/model/he/he-phy.h
+++ b/src/wifi/model/he/he-phy.h
@@ -475,9 +475,9 @@ class HePhy : public VhtPhy
     virtual PhyFieldRxStatus ProcessSigB(Ptr<Event> event, PhyFieldRxStatus status);
 
     /**
-     * Start receiving the PSDU (i.e. the first symbol of the PSDU has arrived) of an UL-OFDMA
+     * Start receiving the PSDU (i.e. the first symbol of the PSDU has arrived) of an OFDMA
      * transmission. This function is called upon the RX event corresponding to the OFDMA part of
-     * the UL MU PPDU.
+     * the MU PPDU.
      *
      * \param event the event holding incoming OFDMA part of the PPDU's information
      */
@@ -527,6 +527,15 @@ class HePhy : public VhtPhy
     uint8_t GetNumberBccEncoders(const WifiTxVector& txVector) const override;
     Time GetSymbolDuration(const WifiTxVector& txVector) const override;
 
+    /**
+     * Start the transmission of the OFDMA part of the MU PPDU.
+     *
+     * \param ppdu the PPDU
+     * \param txVector the TXVECTOR
+     * \param ofdmaDuration the duration of the OFDMA part
+     */
+    void StartTxOfdma(Ptr<const WifiPpdu> ppdu, const WifiTxVector& txVector, Time ofdmaDuration);
+
     /**
      * Notify PHY state helper to switch to CCA busy state,
      *
diff --git a/src/wifi/model/he/he-ppdu.cc b/src/wifi/model/he/he-ppdu.cc
index 46dc8a6f7..37a76d361 100644
--- a/src/wifi/model/he/he-ppdu.cc
+++ b/src/wifi/model/he/he-ppdu.cc
@@ -303,7 +303,7 @@ HePpdu::GetTxPsdFlag() const
 }
 
 void
-HePpdu::SetTxPsdFlag(TxPsdFlag flag)
+HePpdu::SetTxPsdFlag(TxPsdFlag flag) const
 {
     NS_LOG_FUNCTION(this << flag);
     m_txPsdFlag = flag;
diff --git a/src/wifi/model/he/he-ppdu.h b/src/wifi/model/he/he-ppdu.h
index 8efefcb5a..76f1777d1 100644
--- a/src/wifi/model/he/he-ppdu.h
+++ b/src/wifi/model/he/he-ppdu.h
@@ -230,7 +230,7 @@ class HePpdu : public OfdmPpdu
      *
      * \see TxPsdFlag
      */
-    void SetTxPsdFlag(TxPsdFlag flag);
+    void SetTxPsdFlag(TxPsdFlag flag) const;
 
     /**
      * Check if STA ID is in HE SIG-B Content Channel ID
@@ -275,8 +275,8 @@ class HePpdu : public OfdmPpdu
      */
     virtual void SetPhyHeaders(const WifiTxVector& txVector, Time ppduDuration);
 
-    HeSigHeader m_heSig;   //!< the HE-SIG PHY header
-    TxPsdFlag m_txPsdFlag; //!< the transmit power spectral density flag
+    HeSigHeader m_heSig;           //!< the HE-SIG PHY header
+    mutable TxPsdFlag m_txPsdFlag; //!< the transmit power spectral density flag
 
     WifiTxVector::HeMuUserInfoMap m_muUserInfos; //!< HE MU specific per-user information (to be
                                                  //!< removed once HE-SIG-B headers are implemented)