diff -r ff532caf9e15 src/wave/examples/vanet-routing-compare.cc
--- a/src/wave/examples/vanet-routing-compare.cc	Sun Feb 28 22:50:25 2016 +0100
+++ b/src/wave/examples/vanet-routing-compare.cc	Mon Feb 29 16:21:43 2016 +0800
@@ -818,13 +818,13 @@
 void
 WifiPhyStats::PhyTxDrop (std::string context, Ptr<const Packet> packet)
 {
-  NS_LOG_UNCOND ("PHY Tx Drop");
+  //NS_LOG_UNCOND ("PHY Tx Drop");
 }
 
 void
 WifiPhyStats::PhyRxDrop (std::string context, Ptr<const Packet> packet)
 {
-  NS_LOG_UNCOND ("PHY Rx Drop");
+  //NS_LOG_UNCOND ("PHY Rx Drop");
 }
 
 uint32_t
@@ -1605,10 +1605,13 @@
   // which is used to determine the total amount of
   // data transmitted, and then used to calculate
   // the MAC/PHY overhead beyond the app-data
-  Config::Connect ("/NodeList/*/DeviceList/*/Phy/State/Tx", MakeCallback (&WifiPhyStats::PhyTxTrace, m_wifiPhyStats));
-  // TxDrop, RxDrop not working yet.  Not sure what I'm doing wrong.
-  Config::Connect ("/NodeList/*/DeviceList/*/ns3::WifiNetDevice/Phy/PhyTxDrop", MakeCallback (&WifiPhyStats::PhyTxDrop, m_wifiPhyStats));
-  Config::Connect ("/NodeList/*/DeviceList/*/ns3::WifiNetDevice/Phy/PhyRxDrop", MakeCallback (&WifiPhyStats::PhyRxDrop, m_wifiPhyStats));
+  Config::Connect ("/NodeList/*/DeviceList/*/$ns3::WifiNetDevice/Phy/State/Tx", MakeCallback (&WifiPhyStats::PhyTxTrace, m_wifiPhyStats));
+  Config::Connect ("/NodeList/*/DeviceList/*/$ns3::WifiNetDevice/Phy/PhyTxDrop", MakeCallback (&WifiPhyStats::PhyTxDrop, m_wifiPhyStats));
+  Config::Connect ("/NodeList/*/DeviceList/*/$ns3::WifiNetDevice/Phy/PhyRxDrop", MakeCallback (&WifiPhyStats::PhyRxDrop, m_wifiPhyStats));
+
+  Config::Connect ("/NodeList/*/DeviceList/*/$ns3::WaveNetDevice/PhyEntities/*/State/Tx", MakeCallback (&WifiPhyStats::PhyTxTrace, m_wifiPhyStats));
+  Config::Connect ("/NodeList/*/DeviceList/*/$ns3::WaveNetDevice/PhyEntities/*/PhyRxDrop", MakeCallback (&WifiPhyStats::PhyRxDrop, m_wifiPhyStats));
+  Config::Connect ("/NodeList/*/DeviceList/*/$ns3::WaveNetDevice/PhyEntities/*/PhyRxDrop", MakeCallback (&WifiPhyStats::PhyRxDrop, m_wifiPhyStats));
 }
 
 void
diff -r ff532caf9e15 src/wave/model/bsm-application.cc
--- a/src/wave/model/bsm-application.cc	Sun Feb 28 22:50:25 2016 +0100
+++ b/src/wave/model/bsm-application.cc	Mon Feb 29 16:21:43 2016 +0800
@@ -217,6 +217,32 @@
   m_adhocTxInterfaces = &i;
   m_nodeId = nodeId;
   m_txMaxDelay = txMaxDelay;
+
+  // check whether current device is a WAVE device,
+  // so alternating channel access assignment will be support.
+  Ptr<Node> node = Application::GetNode();
+  Ptr<NetDevice> device = node->GetDevice(0);
+  Ptr<WaveNetDevice> waveDevice = DynamicCast<WaveNetDevice>(device);
+  if (waveDevice == 0)
+    return;
+
+  // assign channel access and register txprofile for sending packets
+  if (m_chAccessMode == 1)
+  {
+    // assign alternating channel access for SCH1 and CCH
+    SchInfo info = SchInfo (SCH1, false, EXTENDED_ALTERNATING);
+    Simulator::Schedule (Seconds (0), &WaveNetDevice::StartSch, waveDevice, info);
+  }
+  else
+  {
+    // assign continuous channel access for SCH1
+    SchInfo info = SchInfo (SCH1, false, EXTENDED_CONTINUOUS);
+    Simulator::Schedule (Seconds (0), &WaveNetDevice::StartSch, waveDevice, info);
+  }
+
+  // register a tx profile for IP-based packets
+  const TxProfile txProfile = TxProfile (SCH1);
+  Simulator::Schedule (Seconds (0), &WaveNetDevice::RegisterTxProfile, waveDevice, txProfile);
 }
 
 void
diff -r ff532caf9e15 src/wave/model/wave-net-device.cc
--- a/src/wave/model/wave-net-device.cc	Sun Feb 28 22:50:25 2016 +0100
+++ b/src/wave/model/wave-net-device.cc	Mon Feb 29 16:21:43 2016 +0800
@@ -412,7 +412,7 @@
       txVector.SetTxPowerLevel (txInfo.txPowerLevel);
       txVector.SetMode (txInfo.dataRate);
       HigherLayerTxVectorTag tag = HigherLayerTxVectorTag (txVector, false);
-      packet->AddPacketTag (tag);
+      packet->ReplacePacketTag (tag);
     }
 
   LlcSnapHeader llc;
@@ -422,7 +422,7 @@
   // according to channel number and priority,
   // route the packet to a proper queue.
   QosTag qos = QosTag (txInfo.priority);
-  packet->AddPacketTag (qos);
+  packet->ReplacePacketTag (qos);
   Ptr<WifiMac> mac = GetMac (txInfo.channelNumber);
   Mac48Address realTo = Mac48Address::ConvertFrom (dest);
   mac->NotifyTx (packet);
@@ -618,7 +618,7 @@
       txVector.SetTxPowerLevel (m_txProfile->txPowerLevel);
       txVector.SetMode (m_txProfile->dataRate);
       HigherLayerTxVectorTag tag = HigherLayerTxVectorTag (txVector, m_txProfile->adaptable);
-      packet->AddPacketTag (tag);
+      packet->ReplacePacketTag (tag);
     }
 
   LlcSnapHeader llc;
diff -r ff532caf9e15 src/wifi/model/dcf-manager.cc
--- a/src/wifi/model/dcf-manager.cc	Sun Feb 28 22:50:25 2016 +0100
+++ b/src/wifi/model/dcf-manager.cc	Mon Feb 29 16:21:43 2016 +0800
@@ -474,6 +474,12 @@
     {
       return true;
     }
+  // CCA busy
+  Time lastBusyEnd = m_lastBusyStart + m_lastBusyDuration;
+  if (lastBusyEnd >= Simulator::Now ())
+    {
+      return true;
+    }
   // NAV busy
   Time lastNavEnd = m_lastNavStart + m_lastNavDuration;
   if (lastNavEnd > Simulator::Now ())