diff --git a/src/wifi/model/he/he-phy.cc b/src/wifi/model/he/he-phy.cc
index 040bf4d3c..5a0fe4611 100644
--- a/src/wifi/model/he/he-phy.cc
+++ b/src/wifi/model/he/he-phy.cc
@@ -347,12 +347,12 @@ HePhy::BuildPpdu (const WifiConstPsduMap & psdus, const WifiTxVector& txVector,
 }
 
 void
-HePhy::StartReceivePreamble (Ptr<WifiPpdu> ppdu, RxPowerWattPerChannelBand& rxPowersW,
+HePhy::StartReceivePreamble (Ptr<const WifiPpdu> ppdu, RxPowerWattPerChannelBand& rxPowersW,
                              Time rxDuration)
 {
   NS_LOG_FUNCTION (this << ppdu << rxDuration);
   const WifiTxVector& txVector = ppdu->GetTxVector ();
-  auto hePpdu = DynamicCast<HePpdu> (ppdu);
+  auto hePpdu = DynamicCast<const HePpdu> (ppdu);
   NS_ASSERT (hePpdu);
   HePpdu::TxPsdFlag psdFlag = hePpdu->GetTxPsdFlag ();
   if (txVector.IsUlMu () && psdFlag == HePpdu::PSD_HE_TB_OFDMA_PORTION)
@@ -1033,7 +1033,7 @@ HePhy::GetCenterFrequencyForNonOfdmaPart (const WifiTxVector& txVector, uint16_t
 }
 
 void
-HePhy::StartTx (Ptr<WifiPpdu> ppdu)
+HePhy::StartTx (Ptr<const WifiPpdu> ppdu)
 {
   NS_LOG_FUNCTION (this << ppdu);
   if (ppdu->GetType () == WIFI_PPDU_TYPE_UL_MU)
diff --git a/src/wifi/model/he/he-phy.h b/src/wifi/model/he/he-phy.h
index 07c15375b..77904d77d 100644
--- a/src/wifi/model/he/he-phy.h
+++ b/src/wifi/model/he/he-phy.h
@@ -93,13 +93,13 @@ public:
                            const WifiTxVector& txVector,
                            Time ppduDuration) override;
   Ptr<const WifiPsdu> GetAddressedPsduInPpdu (Ptr<const WifiPpdu> ppdu) const override;
-  void StartReceivePreamble (Ptr<WifiPpdu> ppdu,
+  void StartReceivePreamble (Ptr<const WifiPpdu> ppdu,
                              RxPowerWattPerChannelBand& rxPowersW,
                              Time rxDuration) override;
   void CancelAllEvents (void) override;
   uint16_t GetStaId (const Ptr<const WifiPpdu> ppdu) const override;
   uint16_t GetMeasurementChannelWidth (const Ptr<const WifiPpdu> ppdu) const override;
-  void StartTx (Ptr<WifiPpdu> ppdu) override;
+  void StartTx (Ptr<const WifiPpdu> ppdu) override;
   Time CalculateTxDuration (WifiConstPsduMap psduMap, const WifiTxVector& txVector, WifiPhyBand band) const override;
 
   /**
diff --git a/src/wifi/model/phy-entity.cc b/src/wifi/model/phy-entity.cc
index 32abad45b..ae9e8e773 100644
--- a/src/wifi/model/phy-entity.cc
+++ b/src/wifi/model/phy-entity.cc
@@ -361,7 +361,7 @@ PhyEntity::DoEndReceiveField (WifiPpduField field, Ptr<Event> event)
 }
 
 void
-PhyEntity::StartReceivePreamble (Ptr<WifiPpdu> ppdu, RxPowerWattPerChannelBand& rxPowersW,
+PhyEntity::StartReceivePreamble (Ptr<const WifiPpdu> ppdu, RxPowerWattPerChannelBand& rxPowersW,
                                  Time rxDuration)
 {
   //The total RX power corresponds to the maximum over all the bands
@@ -1062,14 +1062,14 @@ PhyEntity::NotifyPayloadBegin (const WifiTxVector& txVector, const Time& payload
 }
 
 void
-PhyEntity::StartTx (Ptr<WifiPpdu> ppdu)
+PhyEntity::StartTx (Ptr<const WifiPpdu> ppdu)
 {
   NS_LOG_FUNCTION (this << ppdu);
   Transmit (ppdu->GetTxDuration (), ppdu, "transmission");
 }
 
 void
-PhyEntity::Transmit (Time txDuration, Ptr<WifiPpdu> ppdu, std::string type)
+PhyEntity::Transmit (Time txDuration, Ptr<const WifiPpdu> ppdu, std::string type)
 {
   NS_LOG_FUNCTION (this << txDuration << ppdu << type);
   double txPowerWatts = DbmToW (m_wifiPhy->GetTxPowerForTransmission (ppdu) + m_wifiPhy->GetTxGain ());
diff --git a/src/wifi/model/phy-entity.h b/src/wifi/model/phy-entity.h
index 2008e635a..3ea9552c4 100644
--- a/src/wifi/model/phy-entity.h
+++ b/src/wifi/model/phy-entity.h
@@ -358,8 +358,8 @@ public:
    * \param rxPowersW the receive power in W per band
    * \param rxDuration the duration of the PPDU
    */
-  virtual void StartReceivePreamble (Ptr<WifiPpdu> ppdu, RxPowerWattPerChannelBand& rxPowersW,
-                                     Time rxDuration);
+  virtual void StartReceivePreamble (Ptr<const WifiPpdu> ppdu, RxPowerWattPerChannelBand& rxPowersW,
+		                     Time rxDuration);
   /**
    * Start receiving a given field.
    *
@@ -447,7 +447,7 @@ public:
    *
    * \param ppdu the PPDU to send
    */
-  virtual void StartTx (Ptr<WifiPpdu> ppdu);
+  virtual void StartTx (Ptr<const WifiPpdu> ppdu);
 
   /**
    * This function prepares most of the WifiSpectrumSignalParameters
@@ -458,7 +458,7 @@ public:
    * \param ppdu the PPDU to send
    * \param type the type of transmission (for logging)
    */
-  void Transmit (Time txDuration, Ptr<WifiPpdu> ppdu, std::string type);
+  void Transmit (Time txDuration, Ptr<const WifiPpdu> ppdu, std::string type);
 
   /**
    * \param psduMap the PSDU(s) to transmit indexed by STA-ID
diff --git a/src/wifi/model/spectrum-wifi-phy.cc b/src/wifi/model/spectrum-wifi-phy.cc
index 54ba3cd94..8da9162a8 100644
--- a/src/wifi/model/spectrum-wifi-phy.cc
+++ b/src/wifi/model/spectrum-wifi-phy.cc
@@ -402,7 +402,7 @@ SpectrumWifiPhy::CreateWifiSpectrumPhyInterface (Ptr<NetDevice> device)
 }
 
 void
-SpectrumWifiPhy::StartTx (Ptr<WifiPpdu> ppdu)
+SpectrumWifiPhy::StartTx (Ptr<const WifiPpdu> ppdu)
 {
   NS_LOG_FUNCTION (this << ppdu);
   GetPhyEntity (ppdu->GetModulation ())->StartTx (ppdu);
diff --git a/src/wifi/model/spectrum-wifi-phy.h b/src/wifi/model/spectrum-wifi-phy.h
index cc1706147..41fe8e866 100644
--- a/src/wifi/model/spectrum-wifi-phy.h
+++ b/src/wifi/model/spectrum-wifi-phy.h
@@ -67,7 +67,7 @@ public:
   virtual ~SpectrumWifiPhy ();
 
   // Implementation of pure virtual method.
-  void StartTx (Ptr<WifiPpdu> ppdu) override;
+  void StartTx (Ptr<const WifiPpdu> ppdu) override;
   Ptr<Channel> GetChannel (void) const override;
   uint16_t GetGuardBandwidth (uint16_t currentChannelWidth) const override;
   std::tuple<double, double, double> GetTxMaskRejectionParams (void) const override;
diff --git a/src/wifi/model/wifi-phy.cc b/src/wifi/model/wifi-phy.cc
index 467b419b0..2dbff45c5 100644
--- a/src/wifi/model/wifi-phy.cc
+++ b/src/wifi/model/wifi-phy.cc
@@ -1634,7 +1634,7 @@ WifiPhy::Reset (void)
 }
 
 void
-WifiPhy::StartReceivePreamble (Ptr<WifiPpdu> ppdu, RxPowerWattPerChannelBand& rxPowersW, Time rxDuration)
+WifiPhy::StartReceivePreamble (Ptr<const WifiPpdu> ppdu, RxPowerWattPerChannelBand& rxPowersW, Time rxDuration)
 {
   WifiModulationClass modulation = ppdu->GetTxVector ().GetModulationClass ();
   auto it = m_phyEntities.find (modulation);
diff --git a/src/wifi/model/wifi-phy.h b/src/wifi/model/wifi-phy.h
index 3b3324829..0e0b3f4c5 100644
--- a/src/wifi/model/wifi-phy.h
+++ b/src/wifi/model/wifi-phy.h
@@ -104,7 +104,7 @@ public:
    * \param rxPowersW the receive power in W per band
    * \param rxDuration the duration of the PPDU
    */
-  void StartReceivePreamble (Ptr<WifiPpdu> ppdu, RxPowerWattPerChannelBand& rxPowersW, Time rxDuration);
+  void StartReceivePreamble (Ptr<const WifiPpdu> ppdu, RxPowerWattPerChannelBand& rxPowersW, Time rxDuration);
 
   /**
    * Reset PHY at the end of the packet under reception after it has failed the PHY header.
@@ -153,7 +153,7 @@ public:
   /**
    * \param ppdu the PPDU to send
    */
-  virtual void StartTx (Ptr<WifiPpdu> ppdu) = 0;
+  virtual void StartTx (Ptr<const WifiPpdu> ppdu) = 0;
 
   /**
    * Put in sleep mode.
diff --git a/src/wifi/model/wifi-spectrum-signal-parameters.h b/src/wifi/model/wifi-spectrum-signal-parameters.h
index 9ea767cca..80ae0cb3d 100644
--- a/src/wifi/model/wifi-spectrum-signal-parameters.h
+++ b/src/wifi/model/wifi-spectrum-signal-parameters.h
@@ -50,7 +50,7 @@ struct WifiSpectrumSignalParameters : public SpectrumSignalParameters
    */
   WifiSpectrumSignalParameters (const WifiSpectrumSignalParameters& p);
 
-  Ptr<WifiPpdu> ppdu;                  ///< The PPDU being transmitted
+  Ptr<const WifiPpdu> ppdu;            ///< The PPDU being transmitted
   uint16_t txCenterFreq;               ///< the center frequency of the transmitted signal in MHz
 };
 
diff --git a/src/wifi/model/yans-wifi-channel.cc b/src/wifi/model/yans-wifi-channel.cc
index d45cfa2b3..6cbbad859 100644
--- a/src/wifi/model/yans-wifi-channel.cc
+++ b/src/wifi/model/yans-wifi-channel.cc
@@ -103,7 +103,6 @@ YansWifiChannel::Send (Ptr<YansWifiPhy> sender, Ptr<const WifiPpdu> ppdu, double
           double rxPowerDbm = m_loss->CalcRxPower (txPowerDbm, senderMobility, receiverMobility);
           NS_LOG_DEBUG ("propagation: txPower=" << txPowerDbm << "dbm, rxPower=" << rxPowerDbm << "dbm, " <<
                         "distance=" << senderMobility->GetDistanceFrom (receiverMobility) << "m, delay=" << delay);
-          Ptr<WifiPpdu> copy = ppdu->Copy ();
           Ptr<NetDevice> dstNetDevice = (*i)->GetDevice ();
           uint32_t dstNode;
           if (dstNetDevice == 0)
@@ -117,13 +116,13 @@ YansWifiChannel::Send (Ptr<YansWifiPhy> sender, Ptr<const WifiPpdu> ppdu, double
 
           Simulator::ScheduleWithContext (dstNode,
                                           delay, &YansWifiChannel::Receive,
-                                          (*i), copy, rxPowerDbm);
+                                          (*i), ppdu, rxPowerDbm);
         }
     }
 }
 
 void
-YansWifiChannel::Receive (Ptr<YansWifiPhy> phy, Ptr<WifiPpdu> ppdu, double rxPowerDbm)
+YansWifiChannel::Receive (Ptr<YansWifiPhy> phy, Ptr<const WifiPpdu> ppdu, double rxPowerDbm)
 {
   NS_LOG_FUNCTION (phy << ppdu << rxPowerDbm);
   // Do no further processing if signal is too weak
diff --git a/src/wifi/model/yans-wifi-channel.h b/src/wifi/model/yans-wifi-channel.h
index b0cb07b8e..fe7aefd69 100644
--- a/src/wifi/model/yans-wifi-channel.h
+++ b/src/wifi/model/yans-wifi-channel.h
@@ -112,7 +112,7 @@ private:
    * \param ppdu the PPDU being sent
    * \param txPowerDbm the TX power associated to the packet being sent (dBm)
    */
-  static void Receive (Ptr<YansWifiPhy> receiver, Ptr<WifiPpdu> ppdu, double txPowerDbm);
+  static void Receive (Ptr<YansWifiPhy> receiver, Ptr<const WifiPpdu> ppdu, double txPowerDbm);
 
   PhyList m_phyList;                   //!< List of YansWifiPhys connected to this YansWifiChannel
   Ptr<PropagationLossModel> m_loss;    //!< Propagation loss model
diff --git a/src/wifi/model/yans-wifi-phy.cc b/src/wifi/model/yans-wifi-phy.cc
index b373ce746..2060dd990 100644
--- a/src/wifi/model/yans-wifi-phy.cc
+++ b/src/wifi/model/yans-wifi-phy.cc
@@ -86,7 +86,7 @@ YansWifiPhy::SetChannel (const Ptr<YansWifiChannel> channel)
 }
 
 void
-YansWifiPhy::StartTx (Ptr<WifiPpdu> ppdu)
+YansWifiPhy::StartTx (Ptr<const WifiPpdu> ppdu)
 {
   NS_LOG_FUNCTION (this << ppdu);
   NS_LOG_DEBUG ("Start transmission: signal power before antenna gain=" << GetPowerDbm (ppdu->GetTxVector ().GetTxPowerLevel ()) << "dBm");
diff --git a/src/wifi/model/yans-wifi-phy.h b/src/wifi/model/yans-wifi-phy.h
index eb9182c44..94207f9f7 100644
--- a/src/wifi/model/yans-wifi-phy.h
+++ b/src/wifi/model/yans-wifi-phy.h
@@ -57,7 +57,7 @@ public:
   virtual ~YansWifiPhy ();
 
   void SetInterferenceHelper (const Ptr<InterferenceHelper> helper) override;
-  void StartTx (Ptr<WifiPpdu> ppdu) override;
+  void StartTx (Ptr<const WifiPpdu> ppdu) override;
   Ptr<Channel> GetChannel (void) const override;
   uint16_t GetGuardBandwidth (uint16_t currentChannelWidth) const override;
   std::tuple<double, double, double> GetTxMaskRejectionParams (void) const override;
diff --git a/src/wifi/test/wifi-phy-ofdma-test.cc b/src/wifi/test/wifi-phy-ofdma-test.cc
index 13aae19a8..d7ae8e07e 100644
--- a/src/wifi/test/wifi-phy-ofdma-test.cc
+++ b/src/wifi/test/wifi-phy-ofdma-test.cc
@@ -157,7 +157,7 @@ public:
   /**
    * \param ppdu the PPDU to send
    */
-  void StartTx (Ptr<WifiPpdu> ppdu) override;
+  void StartTx (Ptr<const WifiPpdu> ppdu) override;
   /**
    * \param currentChannelWidth channel width of the current transmission (MHz)
    * \return the width of the guard band (MHz) set to 2
@@ -263,7 +263,7 @@ OfdmaSpectrumWifiPhy::SetTriggerFrameUid (uint64_t uid)
 }
 
 void
-OfdmaSpectrumWifiPhy::StartTx (Ptr<WifiPpdu> ppdu)
+OfdmaSpectrumWifiPhy::StartTx (Ptr<const WifiPpdu> ppdu)
 {
   m_phyTxPpduUidTrace (ppdu->GetUid ());
   SpectrumWifiPhy::StartTx (ppdu);