diff --git a/src/wifi/model/mac-low.cc b/src/wifi/model/mac-low.cc
index 0bb590da4..73f2f374f 100644
--- a/src/wifi/model/mac-low.cc
+++ b/src/wifi/model/mac-low.cc
@@ -674,7 +674,7 @@ MacLow::StartTransmission (Ptr<const Packet> packet,
       //queue when previous RTS request has failed.
       m_ampdu = false;
     }
-  else if (m_currentHdr.IsQosData () && m_aggregateQueue[GetTid (packet, *hdr)]->GetNPackets () > 0)
+  else if (m_currentHdr.IsQosData () && !m_aggregateQueue[GetTid (packet, *hdr)]->IsEmpty ())
     {
       //m_aggregateQueue > 0 occurs when a RTS/CTS exchange failed before an A-MPDU transmission.
       //In that case, we transmit the same A-MPDU as previously.
@@ -2026,7 +2026,7 @@ MacLow::SendDataAfterCts (Mac48Address source, Time duration)
   if (m_currentHdr.IsQosData ())
     {
       uint8_t tid = GetTid (m_currentPacket, m_currentHdr);
-      if (m_aggregateQueue[GetTid (m_currentPacket, m_currentHdr)]->GetNPackets () != 0)
+      if (!m_aggregateQueue[GetTid (m_currentPacket, m_currentHdr)]->IsEmpty ())
         {
           for (std::vector<Item>::size_type i = 0; i != m_txPackets[tid].size (); i++)
             {
@@ -3006,7 +3006,7 @@ MacLow::AggregateToAmpdu (Ptr<const Packet> packet, const WifiMacHeader hdr)
 void
 MacLow::FlushAggregateQueue (uint8_t tid)
 {
-  if (m_aggregateQueue[tid]->GetNPackets () > 0)
+  if (!m_aggregateQueue[tid]->IsEmpty ())
     {
       NS_LOG_DEBUG ("Flush aggregate queue");
       m_aggregateQueue[tid]->Flush ();
diff --git a/src/wifi/model/wifi-mac-queue.cc b/src/wifi/model/wifi-mac-queue.cc
index 28bd5ea69..029cc83c8 100644
--- a/src/wifi/model/wifi-mac-queue.cc
+++ b/src/wifi/model/wifi-mac-queue.cc
@@ -163,15 +163,18 @@ WifiMacQueue::Enqueue (Ptr<WifiMacQueueItem> item)
 
   NS_ASSERT_MSG (GetMode () == QueueBase::QUEUE_MODE_PACKETS, "WifiMacQueues must be in packet mode");
 
-  // if the queue is full, check if the time-to-live of the oldest packet has
-  // expired. If so, it can be removed so as to make room for the new packet.
-  if (GetNPackets () == GetMaxPackets ())
+  // if the queue is full, remove the first stale packet (if any) encountered
+  // starting from the head of the queue, in order to make room for the new packet.
+  if (QueueBase::GetNPackets () == GetMaxPackets ())
     {
       auto it = Head ();
-      TtlExceeded (it);
+      while (it != Tail () && !TtlExceeded (it))
+        {
+          it++;
+        }
     }
 
-  if (GetNPackets () == GetMaxPackets () && m_dropPolicy == DROP_OLDEST)
+  if (QueueBase::GetNPackets () == GetMaxPackets () && m_dropPolicy == DROP_OLDEST)
     {
       NS_LOG_DEBUG ("Remove the oldest item in the queue");
       DoRemove (Head ());
@@ -188,15 +191,18 @@ WifiMacQueue::PushFront (Ptr<WifiMacQueueItem> item)
 
   NS_ASSERT_MSG (GetMode () == QueueBase::QUEUE_MODE_PACKETS, "WifiMacQueues must be in packet mode");
 
-  // if the queue is full, check if the time-to-live of the oldest packet has
-  // expired. If so, it can be removed so as to make room for the new packet.
-  if (GetNPackets () == GetMaxPackets ())
+  // if the queue is full, remove the first stale packet (if any) encountered
+  // starting from the head of the queue, in order to make room for the new packet.
+  if (QueueBase::GetNPackets () == GetMaxPackets ())
     {
       auto it = Head ();
-      TtlExceeded (it);
+      while (it != Tail () && !TtlExceeded (it))
+        {
+          it++;
+        }
     }
 
-  if (GetNPackets () == GetMaxPackets () && m_dropPolicy == DROP_OLDEST)
+  if (QueueBase::GetNPackets () == GetMaxPackets () && m_dropPolicy == DROP_OLDEST)
     {
       NS_LOG_DEBUG ("Remove the oldest item in the queue");
       DoRemove (Head ());