diff --git a/src/wifi/model/he/he-phy.cc b/src/wifi/model/he/he-phy.cc
index e21af85e7..fe65f69e7 100644
--- a/src/wifi/model/he/he-phy.cc
+++ b/src/wifi/model/he/he-phy.cc
@@ -73,7 +73,8 @@ const PhyEntity::PpduFormats HePhy::m_hePpduFormats { //Ignoring PE (Packet Exte
 HePhy::HePhy (bool buildModeList /* = true */)
   : VhtPhy (false), //don't add VHT modes to list
     m_trigVectorExpirationTime (Seconds (0)),
-    m_rxHeTbPpdus (0)
+    m_rxHeTbPpdus (0),
+    m_lastPer20MHzDurations ()
 {
   NS_LOG_FUNCTION (this << buildModeList);
   m_bssMembershipSelector = HE_PHY;
@@ -1015,12 +1016,47 @@ HePhy::GetCcaThreshold (const Ptr<const WifiPpdu> ppdu, WifiChannelListType chan
   return std::max (VhtPhy::GetCcaThreshold (ppdu, channelType), obssPdLevel);
 }
 
+void
+HePhy::SwitchMaybeToCcaBusy (const Ptr<const WifiPpdu> ppdu)
+{
+  const auto ccaIndication = GetCcaIndication (ppdu);
+  const auto per20MHzDurations = GetPer20MHzDurations (ppdu);
+  if (ccaIndication.has_value ())
+    {
+      NS_LOG_DEBUG ("CCA busy for " << ccaIndication.value ().second << " during " << ccaIndication.value ().first.As (Time::S));
+      NotifyCcaBusy (ccaIndication.value ().first, ccaIndication.value ().second, per20MHzDurations);
+      return;
+    }
+  if (ppdu)
+    {
+      SwitchMaybeToCcaBusy (nullptr);
+      return;
+    }
+  if (per20MHzDurations != m_lastPer20MHzDurations)
+    {
+      /*
+       * 8.3.5.12.3: For Clause 27 PHYs, this primitive is generated when (...) the per20bitmap parameter changes.
+       */
+      NS_LOG_DEBUG ("per-20MHz CCA durations changed");
+      NotifyCcaBusy (Seconds (0), WIFI_CHANLIST_PRIMARY, per20MHzDurations);
+    }
+}
+
 void
 HePhy::NotifyCcaBusy (const Ptr<const WifiPpdu> ppdu, Time duration, WifiChannelListType channelType)
 {
   NS_LOG_FUNCTION (this << duration << channelType);
   NS_LOG_DEBUG ("CCA busy for " << channelType << " during " << duration.As (Time::S));
-  m_state->SwitchMaybeToCcaBusy (duration, channelType, GetPer20MHzDurations (ppdu));
+  const auto per20MHzDurations = GetPer20MHzDurations (ppdu);
+  NotifyCcaBusy (duration, channelType, per20MHzDurations);
+}
+
+void
+HePhy::NotifyCcaBusy (Time duration, WifiChannelListType channelType, const std::vector<Time>& per20MHzDurations)
+{
+  NS_LOG_FUNCTION (this << duration << channelType);
+  m_state->SwitchMaybeToCcaBusy (duration, channelType, per20MHzDurations);
+  m_lastPer20MHzDurations = per20MHzDurations;
 }
 
 std::vector<Time>
diff --git a/src/wifi/model/he/he-phy.h b/src/wifi/model/he/he-phy.h
index 1e0ba9da2..9e548b14e 100644
--- a/src/wifi/model/he/he-phy.h
+++ b/src/wifi/model/he/he-phy.h
@@ -103,6 +103,7 @@ public:
   uint16_t GetMeasurementChannelWidth (const Ptr<const WifiPpdu> ppdu) const override;
   void StartTx (Ptr<const WifiPpdu> ppdu) override;
   Time CalculateTxDuration (WifiConstPsduMap psduMap, const WifiTxVector& txVector, WifiPhyBand band) const override;
+  void SwitchMaybeToCcaBusy (const Ptr<const WifiPpdu> ppdu) override;
   double GetCcaThreshold (const Ptr<const WifiPpdu> ppdu, WifiChannelListType channelType) const override;
   void NotifyCcaBusy (const Ptr<const WifiPpdu> ppdu, Time duration, WifiChannelListType channelType) override;
 
@@ -479,6 +480,15 @@ private:
   uint8_t GetNumberBccEncoders (const WifiTxVector& txVector) const override;
   Time GetSymbolDuration (const WifiTxVector& txVector) const override;
 
+  /**
+   * Notify PHY state helper to switch to CCA busy state,
+   *
+   * \param duration the duration of the CCA state
+   * \param channelType the channel type for which the CCA busy state is reported.
+   * \param per20MHzDurations the per-20 MHz CCA durations vector
+   */
+  void NotifyCcaBusy (Time duration, WifiChannelListType channelType, const std::vector<Time>& per20MHzDurations);
+
   /**
    * Compute the per-20 MHz CCA durations vector that indicates
    * for how long each 20 MHz subchannel (corresponding to the
@@ -516,8 +526,9 @@ private:
 
   static const PpduFormats m_hePpduFormats; //!< HE PPDU formats
 
-  std::size_t m_rxHeTbPpdus; //!< Number of successfully received HE TB PPDUS
-  Ptr<ObssPdAlgorithm> m_obssPdAlgorithm; //!< OBSS-PD algorithm
+  std::size_t m_rxHeTbPpdus;                 //!< Number of successfully received HE TB PPDUS
+  Ptr<ObssPdAlgorithm> m_obssPdAlgorithm;    //!< OBSS-PD algorithm
+  std::vector<Time> m_lastPer20MHzDurations; //!< Hold the last per-20 MHz CCA durations vector
 }; //class HePhy
 
 } //namespace ns3