diff -r 85f40b38d57c src/devices/wimax/simple-ofdm-wimax-channel.cc
--- a/src/devices/wimax/simple-ofdm-wimax-channel.cc    Wed Apr 07 22:31:55 2010 -0700
+++ b/src/devices/wimax/simple-ofdm-wimax-channel.cc    Wed Apr 07 22:39:09 2010 -0700
@@ -145,20 +145,14 @@
   double rxPowerDbm = 0;
   Ptr<MobilityModel> senderMobility = 0;
   Ptr<MobilityModel> receiverMobility = 0;
-  if (phy->GetMobility ())
-    {
-      senderMobility = phy->GetMobility ()->GetObject<MobilityModel> ();
-    }
+  senderMobility = phy->GetDevice ()->GetNode ()->GetObject<MobilityModel> ();
 
   for (std::list<Ptr<SimpleOfdmWimaxPhy> >::iterator iter = m_phyList.begin (); iter != m_phyList.end (); ++iter)
     {
       double delay = 0;
       if (phy != *iter)
         {
-          if ((*iter)->GetMobility ())
-            {
-              receiverMobility = (*iter)->GetMobility ()->GetObject<MobilityModel> ();
-            }
+          receiverMobility = (*iter)->GetDevice ()->GetNode ()->GetObject<MobilityModel> ();
           if (receiverMobility != 0 && senderMobility != 0 && m_loss != 0)
             {
               delay = (senderMobility->GetDistanceFrom (receiverMobility)) / 300000000LL;