From 2e3dbaea4e2a7e05ce912c413c375549897ac292 Mon Sep 17 00:00:00 2001
From: Stefano Avallone <stavallo@unina.it>
Date: Thu, 6 Jul 2023 09:26:22 +0200
Subject: [PATCH] wifi: Schedule transmission of MU-BARs instead of enqueuing
 them

---
 src/wifi/model/block-ack-manager.cc           | 15 --------
 src/wifi/model/block-ack-manager.h            |  8 -----
 .../model/he/he-frame-exchange-manager.cc     | 34 +++++--------------
 src/wifi/model/he/he-frame-exchange-manager.h |  1 -
 4 files changed, 9 insertions(+), 49 deletions(-)

diff --git a/src/wifi/model/block-ack-manager.cc b/src/wifi/model/block-ack-manager.cc
index 62c213648..fa64cfb96 100644
--- a/src/wifi/model/block-ack-manager.cc
+++ b/src/wifi/model/block-ack-manager.cc
@@ -689,21 +689,6 @@ BlockAckManager::ScheduleBar(const CtrlBAckRequestHeader& reqHdr, const WifiMacH
     m_queue->Enqueue(Create<WifiMpdu>(pkt, hdr));
 }
 
-void
-BlockAckManager::ScheduleMuBar(Ptr<WifiMpdu> muBar)
-{
-    NS_LOG_FUNCTION(this << *muBar);
-    NS_ASSERT(muBar->GetHeader().IsTrigger());
-
-#ifdef NS3_BUILD_PROFILE_DEBUG
-    CtrlTriggerHeader triggerHdr;
-    muBar->GetPacket()->PeekHeader(triggerHdr);
-    NS_ASSERT(triggerHdr.IsMuBar());
-#endif
-
-    m_queue->Enqueue(muBar);
-}
-
 const std::list<BlockAckManager::AgreementKey>&
 BlockAckManager::GetSendBarIfDataQueuedList() const
 {
diff --git a/src/wifi/model/block-ack-manager.h b/src/wifi/model/block-ack-manager.h
index 5e1e68f0a..668fa9c90 100644
--- a/src/wifi/model/block-ack-manager.h
+++ b/src/wifi/model/block-ack-manager.h
@@ -418,14 +418,6 @@ class BlockAckManager : public Object
      * it is placed at the head of the queue, otherwise at the tail.
      */
     void ScheduleBar(const CtrlBAckRequestHeader& reqHdr, const WifiMacHeader& hdr);
-    /**
-     * \param muBar the MU-BAR Trigger Frame to enqueue
-     *
-     * Enqueue the given MU-BAR Trigger Frame into the queue storing the next MU-BAR
-     * frames to transmit. If the given MU-BAR Trigger Frame is retransmitted,
-     * it is placed at the head of the queue, otherwise at the tail.
-     */
-    void ScheduleMuBar(Ptr<WifiMpdu> muBar);
 
     /// agreement key typedef (MAC address and TID)
     using AgreementKey = std::pair<Mac48Address, uint8_t>;
diff --git a/src/wifi/model/he/he-frame-exchange-manager.cc b/src/wifi/model/he/he-frame-exchange-manager.cc
index 804dd9499..f3ce49f81 100644
--- a/src/wifi/model/he/he-frame-exchange-manager.cc
+++ b/src/wifi/model/he/he-frame-exchange-manager.cc
@@ -214,26 +214,6 @@ HeFrameExchangeManager::StartFrameExchange(Ptr<QosTxop> edca, Time availableTime
     return false;
 }
 
-bool
-HeFrameExchangeManager::SendMpduFromBaManager(Ptr<WifiMpdu> mpdu,
-                                              Time availableTime,
-                                              bool initialFrame)
-{
-    NS_LOG_FUNCTION(this << *mpdu << availableTime << initialFrame);
-
-    // First, check if there is a Trigger Frame to be transmitted
-    if (!mpdu->GetHeader().IsTrigger())
-    {
-        // BlockAckReq are handled by the HT FEM
-        return HtFrameExchangeManager::SendMpduFromBaManager(mpdu, availableTime, initialFrame);
-    }
-
-    m_triggerFrame = mpdu;
-
-    SendPsduMap();
-    return true;
-}
-
 void
 HeFrameExchangeManager::SendPsduMapWithProtection(WifiPsduMap psduMap, WifiTxParameters& txParams)
 {
@@ -624,8 +604,7 @@ HeFrameExchangeManager::SendPsduMap()
             // set the UL Length field of the MU-BAR Trigger Frame
             m_trigVector.SetLength(acknowledgment->ulLength);
 
-            NS_ASSERT(m_edca);
-            m_edca->GetBaManager()->ScheduleMuBar(PrepareMuBar(m_trigVector, recipients));
+            m_triggerFrame = PrepareMuBar(m_trigVector, recipients);
         }
         else
         {
@@ -827,7 +806,14 @@ HeFrameExchangeManager::SendPsduMap()
 
     if (timerType == WifiTxTimer::NOT_RUNNING)
     {
-        if (!m_txParams.m_txVector.IsUlMu())
+        if (m_triggerFrame)
+        {
+            NS_LOG_DEBUG("Scheduling MU-BAR " << *m_triggerFrame);
+            Simulator::Schedule(txDuration + m_phy->GetSifs(),
+                                &HeFrameExchangeManager::SendPsduMap,
+                                this);
+        }
+        else if (!m_txParams.m_txVector.IsUlMu())
         {
             Simulator::Schedule(txDuration, &HeFrameExchangeManager::TransmissionSucceeded, this);
         }
@@ -1334,7 +1320,6 @@ HeFrameExchangeManager::BlockAcksInTbPpduTimeout(
     if (m_triggerFrame)
     {
         // this is strictly needed for DL_MU_TF_MU_BAR only
-        DequeueMpdu(m_triggerFrame);
         m_triggerFrame = nullptr;
     }
 
@@ -2441,7 +2426,6 @@ HeFrameExchangeManager::ReceiveMpdu(Ptr<const WifiMpdu> mpdu,
                 if (m_triggerFrame)
                 {
                     // this is strictly needed for DL_MU_TF_MU_BAR only
-                    DequeueMpdu(m_triggerFrame);
                     m_triggerFrame = nullptr;
                 }
 
diff --git a/src/wifi/model/he/he-frame-exchange-manager.h b/src/wifi/model/he/he-frame-exchange-manager.h
index fc29f37be..e4eb73b32 100644
--- a/src/wifi/model/he/he-frame-exchange-manager.h
+++ b/src/wifi/model/he/he-frame-exchange-manager.h
@@ -157,7 +157,6 @@ class HeFrameExchangeManager : public VhtFrameExchangeManager
     Time GetTxDuration(uint32_t ppduPayloadSize,
                        Mac48Address receiver,
                        const WifiTxParameters& txParams) const override;
-    bool SendMpduFromBaManager(Ptr<WifiMpdu> mpdu, Time availableTime, bool initialFrame) override;
     void NormalAckTimeout(Ptr<WifiMpdu> mpdu, const WifiTxVector& txVector) override;
     void BlockAckTimeout(Ptr<WifiPsdu> psdu, const WifiTxVector& txVector) override;
     void CtsTimeout(Ptr<WifiMpdu> rts, const WifiTxVector& txVector) override;