diff --git a/src/wifi/model/interference-helper.cc b/src/wifi/model/interference-helper.cc
--- a/src/wifi/model/interference-helper.cc
+++ b/src/wifi/model/interference-helper.cc
@@ -203,20 +203,26 @@
 InterferenceHelper::AppendEvent (Ptr<InterferenceHelper::Event> event)
 {
   NS_LOG_FUNCTION (this);
-  double previousPowerStart = 0;
-  double previousPowerEnd = 0;
-  previousPowerStart = GetPreviousPosition (event->GetStartTime ())->second.GetPower ();
-  previousPowerEnd = GetPreviousPosition (event->GetEndTime ())->second.GetPower ();
+
+  auto start = m_niChanges.upper_bound (event->GetStartTime ());
+  auto end = m_niChanges.upper_bound (event->GetEndTime ());
+
+  auto startPrev = std::prev(start);
+  auto endPrev = std::prev(end);
+
+  double previousPowerStart = startPrev->second.GetPower ();
+  double previousPowerEnd = endPrev->second.GetPower ();
 
   if (!m_rxing)
     {
       m_firstPower = previousPowerStart;
       // Always leave the first zero power noise event in the list
-      m_niChanges.erase (++(m_niChanges.begin ()),
-                         GetNextPosition (event->GetStartTime ()));
+      m_niChanges.erase (std::next(m_niChanges.begin ()), start);
     }
-  auto first = AddNiChangeEvent (event->GetStartTime (), NiChange (previousPowerStart, event));
-  auto last = AddNiChangeEvent (event->GetEndTime (), NiChange (previousPowerEnd, event));
+
+  auto first = m_niChanges.emplace_hint (start, event->GetStartTime (), NiChange(previousPowerStart, event));
+  auto last = m_niChanges.emplace_hint (end, event->GetEndTime (), NiChange(previousPowerEnd, event));
+
   for (auto i = first; i != last; ++i)
     {
       i->second.AddPower (event->GetRxPowerW ());
@@ -810,7 +816,7 @@
 InterferenceHelper::NiChanges::iterator
 InterferenceHelper::AddNiChangeEvent (Time moment, NiChange change)
 {
-  return m_niChanges.insert (GetNextPosition (moment), std::make_pair (moment, change));
+  return m_niChanges.emplace (moment, change);
 }
 
 void