# HG changeset patch
# User Timo Bingmann <timo.bingmann@student.kit.edu>
# Date 1240064026 -7200
# Node ID 1f5866271cd69c6933c0315d3dc7591172b7dc03
# Parent  72b17c213affcbea3ce48b94b0cd3393e183b588
Correction of DCF collision detection time and backoff end for simulation start.

diff -r a07440ab970c src/devices/wifi/dcf-manager.cc
--- a/src/devices/wifi/dcf-manager.cc	Fri Apr 24 08:52:46 2009 +0200
+++ b/src/devices/wifi/dcf-manager.cc	Fri Apr 24 09:50:40 2009 +0200
@@ -41,7 +41,7 @@ namespace ns3 {
 
 DcfState::DcfState ()
   : m_backoffSlots (0),
-    m_backoffStart (Seconds (0.0)),
+    m_backoffStart (Seconds (-1.0)),
     m_cwMin (0),
     m_cwMax (0),
     m_cw (0),
@@ -208,16 +208,16 @@ private:
  ****************************************************************/
 
 DcfManager::DcfManager ()
-  : m_lastNavStart (MicroSeconds (0)),
-    m_lastNavDuration (MicroSeconds (0)),
-    m_lastRxStart (MicroSeconds (0)),
-    m_lastRxDuration (MicroSeconds (0)),
+  : m_lastNavStart (Seconds (-1.0)),
+    m_lastNavDuration (Seconds (0.0)),
+    m_lastRxStart (Seconds (-1.0)),
+    m_lastRxDuration (Seconds (0.0)),
     m_lastRxReceivedOk (true),
-    m_lastRxEnd (MicroSeconds (0)),
-    m_lastTxStart (MicroSeconds (0)),
-    m_lastTxDuration (MicroSeconds (0)),
-    m_lastBusyStart (MicroSeconds (0)),
-    m_lastBusyDuration (MicroSeconds (0)),
+    m_lastRxEnd (Seconds (-1.0)),
+    m_lastTxStart (Seconds (-1.0)),
+    m_lastTxDuration (Seconds (0.0)),
+    m_lastBusyStart (Seconds (-1.0)),
+    m_lastBusyDuration (Seconds (0.0)),
     m_rxing (false),
     m_slotTime (Seconds (0.0)),
     m_sifs (Seconds (0.0)),
@@ -323,8 +323,7 @@ DcfManager::RequestAccess (DcfState *sta
    * If there is a collision, generate a backoff
    * by notifying the collision to the user.
    */
-  if (state->GetBackoffSlots () == 0 && 
-      IsBusy ())
+  if (GetBackoffEndFor (state) < Simulator::Now () && IsBusy ())
     {
       MY_DEBUG ("medium is busy: collision");
       /* someone else has accessed the medium.