wifi: Allow using BSRP TFs as ICFs for EMLSR clients

RELEASE_NOTES.md

@@ -36,6 +36,7 @@ The required Doxygen version for documentation generation is version 1.11.
 - (applications) - The `ThreeGppHttpServer::LocalAddress` and `ThreeGppHttpServer::LocalPort` attributes have been renamed to `ThreeGppHttpServer::Remote` and `ThreeGppHttpServer::Port`, respectively.
 - (applications) - It is now possible to specify the address on which to bind the listening socket for UdpServer via the `Local` attribute.
 - (applications) - It is now possible to specify a port only for PacketSink to listen to any address (both IPv4 and IPv6).
+- (wifi) - Added a `WifiDefaultProtectionManager::SkipMuRtsBeforeBsrp` attribute to avoid using MU-RTS to protect the transmission of a BSRP Trigger Frame. If this attribute is set to true (which is the default value), BSRP Trigger Frames can be used as Initial Control Frames for EMLSR clients
 
 ### Bugs fixed
 

src/wifi/model/wifi-default-protection-manager.cc

@@ -48,6 +48,12 @@ WifiDefaultProtectionManager::GetTypeId()
                           "Initial Control Frame to an EMLSR client).",
                           BooleanValue(false),
                           MakeBooleanAccessor(&WifiDefaultProtectionManager::m_singleRtsPerTxop),
+                          MakeBooleanChecker())
+            .AddAttribute("SkipMuRtsBeforeBsrp",
+                          "If enabled, MU-RTS is not used to protect the transmission of a BSRP "
+                          "Trigger Frame.",
+                          BooleanValue(true),
+                          MakeBooleanAccessor(&WifiDefaultProtectionManager::m_skipMuRtsBeforeBsrp),
                           MakeBooleanChecker());
     return tid;
 }
@@ -376,6 +382,10 @@ WifiDefaultProtectionManager::TryUlMuTransmission(Ptr<const WifiMpdu> mpdu,
         (m_sendMuRts && !allProtected && (!m_singleRtsPerTxop || protectedStas.empty())) ||
         isUnprotectedEmlsrDst;
 
+    // if we are sending a BSRP TF and SkipMuRtsBeforeBsrpTf is true, do not use MU-RTS (even in
+    // case of unprotected EMLSR, because the BSRP TF is an ICF)
+    needMuRts = needMuRts && (!m_skipMuRtsBeforeBsrp || !trigger.IsBsrp());
+
     if (!needMuRts)
     {
         // No protection needed

src/wifi/model/wifi-default-protection-manager.h

@@ -87,8 +87,9 @@ class WifiDefaultProtectionManager : public WifiProtectionManager
     virtual std::unique_ptr<WifiProtection> TryUlMuTransmission(Ptr<const WifiMpdu> mpdu,
                                                                 const WifiTxParameters& txParams);
 
-    bool m_sendMuRts;        //!< true for sending an MU-RTS to protect DL MU PPDUs
-    bool m_singleRtsPerTxop; //!< true for using protection only once in a TXOP
+    bool m_sendMuRts;           //!< true for sending an MU-RTS to protect DL MU PPDUs
+    bool m_singleRtsPerTxop;    //!< true for using protection only once in a TXOP
+    bool m_skipMuRtsBeforeBsrp; //!< whether to skip MU-RTS before BSRP TF
 };
 
 } // namespace ns3

src/wifi/test/wifi-mac-ofdma-test.cc

@@ -2158,7 +2158,9 @@ OfdmaAckSequenceTest::DoRun()
         TimeValue(m_defaultTbPpduDuration));
     mac.SetProtectionManager("ns3::WifiDefaultProtectionManager",
                              "EnableMuRts",
-                             BooleanValue(true));
+                             BooleanValue(true),
+                             "SkipMuRtsBeforeBsrp",
+                             BooleanValue(false));
     mac.SetAckManager("ns3::WifiDefaultAckManager",
                       "DlMuAckSequenceType",
                       EnumValue(m_dlMuAckType));