channel switching support for wifi

src/devices/wifi/dcf-manager.cc

 /* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
 /*
  * Copyright (c) 2005,2006 INRIA
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as 
  * published by the Free Software Foundation;
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 135 matching lines @@
 }
 void 
 DcfState::NotifyCollision (void)
 {
   DoNotifyCollision ();
 }
 void 
 DcfState::NotifyInternalCollision (void)
 {
   DoNotifyInternalCollision ();
+}
+void 
+DcfState::NotifyChannelSwitching (void) 
+{
+  DoNotifyChannelSwitching ();
 }
 
 
 /***************************************************************
  *         Listener for Nav events. Forwards to DcfManager
  ***************************************************************/
 
 class LowDcfListener : public ns3::MacLowDcfListener {
 public:
   LowDcfListener (ns3::DcfManager *dcf)
@@ skipping 37 matching lines @@
     m_dcf->NotifyRxEndOkNow ();
   }
   virtual void NotifyRxEndError (void) {
     m_dcf->NotifyRxEndErrorNow ();
   }
   virtual void NotifyTxStart (Time duration) {
     m_dcf->NotifyTxStartNow (duration);
   }
   virtual void NotifyMaybeCcaBusyStart (Time duration) {
     m_dcf->NotifyMaybeCcaBusyStartNow (duration);
+  }
+  virtual void NotifySwitchingStart (Time duration) { 
+    m_dcf->NotifySwitchingStartNow (duration);
   }
 private:
   ns3::DcfManager *m_dcf;
 };
 
 /****************************************************************
  *      Implement the DCF manager of all DCF state holders
  ****************************************************************/
 
 DcfManager::DcfManager ()
   : m_lastAckTimeoutEnd (MicroSeconds (0)),
     m_lastCtsTimeoutEnd (MicroSeconds (0)),
     m_lastNavStart (MicroSeconds (0)),
     m_lastNavDuration (MicroSeconds (0)),
     m_lastRxStart (MicroSeconds (0)),
     m_lastRxDuration (MicroSeconds (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_lastSwitchingStart (MicroSeconds (0)), 
+    m_lastSwitchingDuration (MicroSeconds (0)), 
     m_rxing (false),
     m_slotTime (Seconds (0.0)),
     m_sifs (Seconds (0.0)),
     m_phyListener (0),
     m_lowListener (0)
 {}
 
 DcfManager::~DcfManager ()
 {
   delete m_phyListener;
@@ skipping 67 matching lines @@
 DcfManager::MostRecent (Time a, Time b, Time c, Time d, Time e, Time f) const
 {
   Time g = Max (a, b);
   Time h = Max (c, d);
   Time i = Max (e, f);
   Time k = Max (g, h);
   Time retval = Max (k, i);
   return retval;
 }
 
+Time
+DcfManager::MostRecent (Time a, Time b, Time c, Time d, Time e, Time f, Time g) const
+{
+  Time h = Max (a, b);
+  Time i = Max (c, d);
+  Time j = Max (e, f);
+  Time k = Max (h, i);
+  Time l = Max (j, g);
+  Time retval = Max (k, l);
+  return retval;
+}
+
 bool 
 DcfManager::IsBusy (void) const
 {
   // PHY busy
   if (m_rxing) 
     {
       return true;
     }
   Time lastTxEnd = m_lastTxStart + m_lastTxDuration;
   if (lastTxEnd > Simulator::Now ()) 
@@ skipping 115 matching lines @@
     } 
   else 
     {
       rxAccessStart = m_lastRxStart + m_lastRxDuration + m_sifs;
     }
   Time busyAccessStart = m_lastBusyStart + m_lastBusyDuration + m_sifs;
   Time txAccessStart = m_lastTxStart + m_lastTxDuration + m_sifs;
   Time navAccessStart = m_lastNavStart + m_lastNavDuration + m_sifs;
   Time ackTimeoutAccessStart = m_lastAckTimeoutEnd + m_sifs;
   Time ctsTimeoutAccessStart = m_lastCtsTimeoutEnd + m_sifs;
+  Time switchingAccessStart = m_lastSwitchingStart + m_lastSwitchingDuration + m_sifs; 
   Time accessGrantedStart = MostRecent (rxAccessStart, 
                                         busyAccessStart,
                                         txAccessStart, 
                                         navAccessStart,
                                         ackTimeoutAccessStart,
-                                        ctsTimeoutAccessStart
+                                        ctsTimeoutAccessStart,
+                                        switchingAccessStart 
                                         );
   NS_LOG_INFO ("access grant start=" << accessGrantedStart <<
                ", rx access start=" << rxAccessStart <<
                ", busy access start=" << busyAccessStart <<
                ", tx access start=" << txAccessStart <<
                ", nav access start=" << navAccessStart);
   return accessGrantedStart;
 }
 
 Time
@@ skipping 116 matching lines @@
   m_lastTxDuration = duration;
 }
 void 
 DcfManager::NotifyMaybeCcaBusyStartNow (Time duration)
 {
   MY_DEBUG ("busy start for "<<duration);
   UpdateBackoff ();
   m_lastBusyStart = Simulator::Now ();
   m_lastBusyDuration = duration;
 }
+
+
+void 
+DcfManager::NotifySwitchingStartNow (Time duration)

[Mathieu Lacage, 2009/08/19 08:19:12]

I would like to see an associated test in dcf-manager-test.cc for this function
to exercise its many code paths.

[Ramon Bauza, 2009/09/08 11:36:08]

On 2009/08/19 08:19:12, Mathieu Lacage wrote:
> I would like to see an associated test in dcf-manager-test.cc for this
function
> to exercise its many code paths.

done.

+{
+  Time now = Simulator::Now ();
+  NS_ASSERT (m_lastTxStart + m_lastTxDuration < now);
+  NS_ASSERT (m_lastSwitchingStart + m_lastSwitchingDuration < now);
+
+  if (m_rxing)
+  {

[Mathieu Lacage, 2009/08/19 08:19:12]

indent

[Ramon Bauza, 2009/09/08 11:36:08]

On 2009/08/19 08:19:12, Mathieu Lacage wrote:
> indent

done.

+    // channel switching during packet reception
+    m_lastRxEnd = Simulator::Now ();
+    m_lastRxDuration = m_lastRxEnd - m_lastRxStart;
+    m_lastRxReceivedOk = true;
+    m_rxing = false;
+  }
+  if (m_lastNavStart + m_lastNavDuration > now)
+    {
+      m_lastNavDuration = now - m_lastNavStart;
+    }
+  if (m_lastBusyStart + m_lastBusyDuration > now)
+    {
+      m_lastBusyDuration = now - m_lastBusyStart;
+    }
+  if (m_lastAckTimeoutEnd > now)
+    {
+      m_lastAckTimeoutEnd = now;
+    }
+  if (m_lastCtsTimeoutEnd > now)
+    {
+      m_lastCtsTimeoutEnd = now;
+    }
+
+  // Cancel timeout
+  if (m_accessTimeout.IsRunning ())
+    {
+      m_accessTimeout.Cancel ();
+    }
+
+  // Reset backoffs
+  for (States::iterator i = m_states.begin (); i != m_states.end (); i++)
+    {
+      DcfState *state = *i;
+      Time backoffEnd = GetBackoffEndFor (state);
+      if (backoffEnd >= now)
+        {
+          uint32_t remainingSlots = state->GetBackoffSlots ();
+          state->UpdateBackoffSlotsNow (remainingSlots, now);
+          NS_ASSERT(state->GetBackoffSlots()==0);
+        }
+      state->ResetCw();
+      state->m_accessRequested = false;
+      state->NotifyChannelSwitching();
+    } 
+ 
+  MY_DEBUG ("switching start for "<<duration);
+  m_lastSwitchingStart = Simulator::Now ();
+  m_lastSwitchingDuration = duration;
+
+}
+
 void 
 DcfManager::NotifyNavResetNow (Time duration)
 {
   MY_DEBUG ("nav reset for="<<duration);
   UpdateBackoff ();
   m_lastNavStart = Simulator::Now ();
   m_lastNavDuration = duration;
   UpdateBackoff ();
   /**
    * If the nav reset indicates an end-of-nav which is earlier
@@ skipping 34 matching lines @@
 {
   m_lastCtsTimeoutEnd = Simulator::Now () + duration;
 }
 void
 DcfManager::NotifyCtsTimeoutResetNow ()
 {
   m_lastCtsTimeoutEnd = Simulator::Now ();
   DoRestartAccessTimeoutIfNeeded ();
 }
 } // namespace ns3