wifi: Enable protection for DL MU PPDUs including one PSDU

src/wifi/model/frame-exchange-manager.cc

@@ -810,28 +810,42 @@ FrameExchangeManager::CtsTimeout (Ptr<WifiMacQueueItem> rts, const WifiTxVector&
 {
   NS_LOG_FUNCTION (this << *rts << txVector);
 
-  m_mac->GetWifiRemoteStationManager ()->ReportRtsFailed (m_mpdu->GetHeader ());
+  DoCtsTimeout (Create<WifiPsdu> (m_mpdu, true));
+  m_mpdu = nullptr;
+}
 
-  if (!m_mac->GetWifiRemoteStationManager ()->NeedRetransmission (m_mpdu))
+void
+FrameExchangeManager::DoCtsTimeout (Ptr<WifiPsdu> psdu)
+{
+  NS_LOG_FUNCTION (this << *psdu);
+
+  m_mac->GetWifiRemoteStationManager ()->ReportRtsFailed (psdu->GetHeader (0));
+
+  if (!m_mac->GetWifiRemoteStationManager ()->NeedRetransmission (*psdu->begin ()))
     {
-      NS_LOG_DEBUG ("Missed CTS, discard MPDU");
-      // Dequeue the MPDU if it is stored in a queue
-      DequeueMpdu (m_mpdu);
-      NotifyPacketDiscarded (m_mpdu);
-      m_mac->GetWifiRemoteStationManager ()->ReportFinalRtsFailed (m_mpdu->GetHeader ());
+      NS_LOG_DEBUG ("Missed CTS, discard MPDU(s)");
+      m_mac->GetWifiRemoteStationManager ()->ReportFinalRtsFailed (psdu->GetHeader (0));
+      for (const auto& mpdu : *PeekPointer (psdu))
+        {
+          // Dequeue the MPDU if it is stored in a queue
+          DequeueMpdu (mpdu);
+          NotifyPacketDiscarded (mpdu);
+        }
       m_dcf->ResetCw ();
     }
   else
     {
-      NS_LOG_DEBUG ("Missed CTS, retransmit RTS");
+      NS_LOG_DEBUG ("Missed CTS, retransmit MPDU(s)");
       m_dcf->UpdateFailedCw ();
     }
-  // Make the sequence number of the MPDU available again if the MPDU has never
-  // been transmitted, both in case the MPDU has been discarded and in case the
-  // MPDU has to be transmitted (because a new sequence number is assigned to
+  // Make the sequence numbers of the MPDUs available again if the MPDUs have never
+  // been transmitted, both in case the MPDUs have been discarded and in case the
+  // MPDUs have to be transmitted (because a new sequence number is assigned to
   // MPDUs that have never been transmitted and are selected for transmission)
-  ReleaseSequenceNumber (m_mpdu);
-  m_mpdu = 0;
+  for (const auto& mpdu : *PeekPointer (psdu))
+    {
+      ReleaseSequenceNumber (mpdu);
+    }
   TransmissionFailed ();
 }
 

src/wifi/model/frame-exchange-manager.h

@@ -531,6 +531,13 @@ protected:
    * \param txVector the TXVECTOR used to transmit the RTS frame
    */
   virtual void CtsTimeout (Ptr<WifiMacQueueItem> rts, const WifiTxVector& txVector);
+  /**
+   * Take required actions when the CTS timer fired after sending an RTS to
+   * protect the given PSDU expires.
+   *
+   * \param psdu the PSDU protected by the failed RTS
+   */
+  void DoCtsTimeout (Ptr<WifiPsdu> psdu);
 
 private:
   /**

src/wifi/model/he/he-frame-exchange-manager.cc

@@ -227,7 +227,12 @@ HeFrameExchangeManager::SendPsduMapWithProtection (WifiPsduMap psduMap, WifiTxPa
       WifiAckManager::SetQosAckPolicy (psdu.second, m_txParams.m_acknowledgment.get ());
     }
 
-  if (m_txParams.m_protection->method == WifiProtection::NONE)
+  if (m_txParams.m_protection->method == WifiProtection::RTS_CTS)
+    {
+      NS_ABORT_MSG_IF (m_psduMap.size () > 1, "Cannot use RTS/CTS with MU PPDUs");
+      SendRts (m_txParams);
+    }
+  else if (m_txParams.m_protection->method == WifiProtection::NONE)
     {
       SendPsduMap ();
     }
@@ -250,6 +255,24 @@ HeFrameExchangeManager::GetPsduTo (Mac48Address to, const WifiPsduMap& psduMap)
   return nullptr;
 }
 
+void
+HeFrameExchangeManager::CtsTimeout (Ptr<WifiMacQueueItem> rts, const WifiTxVector& txVector)
+{
+  NS_LOG_FUNCTION (this << *rts << txVector);
+
+  if (m_psduMap.empty ())
+    {
+      // A CTS Timeout occurred when protecting a single PSDU that is not included
+      // in a DL MU PPDU is handled by the parent classes
+      VhtFrameExchangeManager::CtsTimeout (rts, txVector);
+      return;
+    }
+
+  NS_ABORT_MSG_IF (m_psduMap.size () > 1, "RTS/CTS cannot be used to protect an MU PPDU");
+  DoCtsTimeout (m_psduMap.begin ()->second);
+  m_psduMap.clear ();
+}
+
 void
 HeFrameExchangeManager::SendPsduMap (void)
 {
@@ -1455,7 +1478,26 @@ HeFrameExchangeManager::ReceiveMpdu (Ptr<WifiMacQueueItem> mpdu, RxSignalInfo rx
 
   if (hdr.IsCtl ())
     {
-      if (hdr.IsAck () && m_txTimer.IsRunning ()
+      if (hdr.IsCts () && m_txTimer.IsRunning () && m_txTimer.GetReason () == WifiTxTimer::WAIT_CTS
+          && m_psduMap.size () == 1)
+        {
+          NS_ABORT_MSG_IF (inAmpdu, "Received CTS as part of an A-MPDU");
+          NS_ASSERT (hdr.GetAddr1 () == m_self);
+
+          Mac48Address sender = m_psduMap.begin ()->second->GetAddr1 ();
+          NS_LOG_DEBUG ("Received CTS from=" << sender);
+
+          SnrTag tag;
+          mpdu->GetPacket ()->PeekPacketTag (tag);
+          m_mac->GetWifiRemoteStationManager ()->ReportRxOk (sender, rxSignalInfo, txVector);
+          m_mac->GetWifiRemoteStationManager ()->ReportRtsOk (m_psduMap.begin ()->second->GetHeader (0),
+                                                              rxSignalInfo.snr, txVector.GetMode (), tag.Get ());
+
+          m_txTimer.Cancel ();
+          m_channelAccessManager->NotifyCtsTimeoutResetNow ();
+          Simulator::Schedule (m_phy->GetSifs (), &HeFrameExchangeManager::SendPsduMap, this);
+        }
+      else if (hdr.IsAck () && m_txTimer.IsRunning ()
           && m_txTimer.GetReason () == WifiTxTimer::WAIT_NORMAL_ACK_AFTER_DL_MU_PPDU)
         {
           NS_ASSERT (hdr.GetAddr1 () == m_self);

src/wifi/model/he/he-frame-exchange-manager.h

@@ -101,6 +101,7 @@ protected:
   Time GetTxDuration (uint32_t ppduPayloadSize, Mac48Address receiver,
                       const WifiTxParameters& txParams) const override;
   bool SendMpduFromBaManager (Ptr<QosTxop> edca, Time availableTime, bool initialFrame) override;
+  void CtsTimeout (Ptr<WifiMacQueueItem> rts, const WifiTxVector& txVector) override;
 
   /**
    * Send a map of PSDUs as a DL MU PPDU.

src/wifi/model/ht/ht-frame-exchange-manager.cc

@@ -768,36 +768,8 @@ HtFrameExchangeManager::CtsTimeout (Ptr<WifiMacQueueItem> rts, const WifiTxVecto
       return;
     }
 
-  NS_ASSERT (m_psdu->GetNMpdus () > 1);
-  m_mac->GetWifiRemoteStationManager ()->ReportRtsFailed (m_psdu->GetHeader (0));
-
-  if (!m_mac->GetWifiRemoteStationManager ()->NeedRetransmission (*m_psdu->begin ()))
-    {
-      NS_LOG_DEBUG ("Missed CTS, discard MPDUs");
-      m_mac->GetWifiRemoteStationManager ()->ReportFinalRtsFailed (m_psdu->GetHeader (0));
-      // Dequeue the MPDUs if they are stored in a queue
-      DequeuePsdu (m_psdu);
-      for (const auto& mpdu : *PeekPointer (m_psdu))
-        {
-          NotifyPacketDiscarded (mpdu);
-        }
-      m_edca->ResetCw ();
-    }
-  else
-    {
-      NS_LOG_DEBUG ("Missed CTS, retransmit MPDUs");
-      m_edca->UpdateFailedCw ();
-    }
-  // Make the sequence numbers of the MPDUs available again if the MPDUs have never
-  // been transmitted, both in case the MPDUs have been discarded and in case the
-  // MPDUs have to be transmitted (because a new sequence number is assigned to
-  // MPDUs that have never been transmitted and are selected for transmission)
-  for (const auto& mpdu : *PeekPointer (m_psdu))
-    {
-      ReleaseSequenceNumber (mpdu);
-    }
-  m_psdu = 0;
-  TransmissionFailed ();
+  DoCtsTimeout (m_psdu);
+  m_psdu = nullptr;
 }
 
 void