diff --git a/src/devices/wifi/mac-high-nqsta.cc b/src/devices/wifi/mac-high-nqsta.cc
new file mode 100644
index 000000000..5720786e0
--- /dev/null
+++ b/src/devices/wifi/mac-high-nqsta.cc
@@ -0,0 +1,380 @@
+/* -*-  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
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
+ */
+
+#include "ns3/packet.h"
+#include "ns3/simulator.h"
+#include "ns3/watchdog.h"
+#include "ns3/assert.h"
+
+#include "mac-high-nqsta.h"
+#include "wifi-mac-header.h"
+#include "wifi-net-device.h"
+#include "mgt-headers.h"
+#include "wifi-phy.h"
+#include "dca-txop.h"
+
+#define noNQSTA_DEBUG 1
+
+#ifdef NQSTA_DEBUG
+#include <iostream>
+#  define TRACE(x) \
+  std::cout << "NQSTA now=" << Simulator::Now () << " " << x << std::endl;
+#else
+#  define TRACE(x)
+#endif
+
+/*
+ * The state machine for this NQSTA is:
+ --------------            -----------
+ | Associated |   <--------------------      ------->    | Refused |
+ --------------      \    /      -----------
+    \           \  /
+     \    -----------------     -----------------------------
+      \-> | Beacon Missed | --> | Wait Association Response |
+    -----------------     -----------------------------
+    \           ^
+     \          |
+      \    -----------------------
+       \-> | Wait Probe Response |
+           -----------------------
+ */
+
+
+namespace ns3 {
+
+MacHighNqsta::MacHighNqsta ()
+  : m_state (BEACON_MISSED),
+    m_probeRequestTimeout (Seconds (0.5)),
+    m_assocRequestTimeout (Seconds (0.5)),
+    m_probeRequestEvent (),
+    m_assocRequestEvent (),
+    m_beaconWatchdog (new Watchdog ())
+{
+  m_beaconWatchdog->SetFunction (&MacHighNqsta::MissedBeacons, this);
+  // this is the default value for the number of beacons missed 
+  // before attempting to reassociate.
+  m_maxMissedBeacons = 10;
+}
+
+MacHighNqsta::~MacHighNqsta ()
+{}
+
+void 
+MacHighNqsta::SetSupportedRates (SupportedRates rates)
+{
+  m_rates = rates;
+}
+void 
+MacHighNqsta::SetDcaTxop (DcaTxop *dca)
+{
+  m_dca = dca;
+}
+void 
+MacHighNqsta::SetInterface (WifiNetDevice *interface)
+{
+  m_interface = interface;
+}
+void 
+MacHighNqsta::SetForwardCallback (ForwardCallback callback)
+{
+  m_forward = callback;
+}
+void 
+MacHighNqsta::SetAssociatedCallback (AssociatedCallback callback)
+{
+  m_associatedCallback = callback;
+}
+void 
+MacHighNqsta::SetDisAssociatedCallback (DisAssociatedCallback callback)
+{
+  m_disAssociatedCallback = callback;
+}
+void 
+MacHighNqsta::SetMaxMissedBeacons (uint32_t missed)
+{
+  m_maxMissedBeacons = missed;
+}
+void 
+MacHighNqsta::SetProbeRequestTimeout (Time timeout)
+{
+  m_probeRequestTimeout = timeout;
+}
+void 
+MacHighNqsta::SetAssocRequestTimeout (Time timeout)
+{
+  m_assocRequestTimeout = timeout;
+}
+
+Mac48Address 
+MacHighNqsta::GetBssid (void) const
+{
+  return m_bssid;
+}
+void 
+MacHighNqsta::SetBssid (Mac48Address bssid)
+{
+  m_bssid = bssid;
+
+}
+void 
+MacHighNqsta::StartActiveAssociation (void)
+{
+  TryToEnsureAssociated ();
+}
+
+Mac48Address
+MacHighNqsta::GetBroadcastBssid (void)
+{
+  return Mac48Address::GetBroadcast ();
+}
+SupportedRates
+MacHighNqsta::GetSupportedRates (void)
+{
+  return m_rates;
+}
+
+void
+MacHighNqsta::SendProbeRequest (void)
+{
+  TRACE ("send probe request");
+  WifiMacHeader hdr;
+  hdr.SetProbeReq ();
+  hdr.SetAddr1 (GetBroadcastBssid ());
+  hdr.SetAddr2 (m_interface->GetSelfAddress ());
+  hdr.SetAddr3 (GetBroadcastBssid ());
+  hdr.SetDsNotFrom ();
+  hdr.SetDsNotTo ();
+  Packet packet;
+  MgtProbeRequestHeader probe;
+  probe.SetSsid (m_interface->GetSsid ());
+  SupportedRates rates = GetSupportedRates ();
+  probe.SetSupportedRates (rates);
+  packet.AddHeader (probe);
+  
+  m_dca->Queue (packet, hdr);
+
+  m_probeRequestEvent = Simulator::Schedule (m_probeRequestTimeout,
+                                             &MacHighNqsta::ProbeRequestTimeout, this);
+}
+
+void
+MacHighNqsta::SendAssociationRequest ()
+{
+  TRACE ("send assoc request");
+  WifiMacHeader hdr;
+  hdr.SetAssocReq ();
+  hdr.SetAddr1 (GetBssid ());
+  hdr.SetAddr2 (m_interface->GetSelfAddress ());
+  hdr.SetAddr3 (GetBssid ());
+  hdr.SetDsNotFrom ();
+  hdr.SetDsNotTo ();
+  Packet packet;
+  MgtAssocRequestHeader assoc;
+  assoc.SetSsid (m_interface->GetSsid ());
+  SupportedRates rates = GetSupportedRates ();
+  assoc.SetSupportedRates (rates);
+  packet.AddHeader (assoc);
+  
+  m_dca->Queue (packet, hdr);
+
+  m_assocRequestEvent = Simulator::Schedule (m_assocRequestTimeout,
+                                             &MacHighNqsta::AssocRequestTimeout, this);
+}
+void
+MacHighNqsta::TryToEnsureAssociated (void)
+{
+  switch (m_state) {
+  case ASSOCIATED:
+    return;
+    break;
+  case WAIT_PROBE_RESP:
+    /* we have sent a probe request earlier so we
+       do not need to re-send a probe request immediately.
+       We just need to wait until probe-request-timeout
+       or until we get a probe response
+     */
+    break;
+  case BEACON_MISSED:
+    /* we were associated but we missed a bunch of beacons
+     * so we should assume we are not associated anymore.
+     * We try to initiate a probe request now.
+     */
+    m_disAssociatedCallback ();
+    m_state = WAIT_PROBE_RESP;
+    SendProbeRequest ();
+    break;
+  case WAIT_ASSOC_RESP:
+    /* we have sent an assoc request so we do not need to
+       re-send an assoc request right now. We just need to
+       wait until either assoc-request-timeout or until
+       we get an assoc response.
+     */
+    break;
+  case REFUSED:
+    /* we have sent an assoc request and received a negative
+       assoc resp. We wait until someone restarts an 
+       association with a given ssid.
+     */
+    break;
+  }
+}
+
+void
+MacHighNqsta::AssocRequestTimeout (void)
+{
+  TRACE ("assoc request timeout");
+  m_state = WAIT_ASSOC_RESP;
+  SendAssociationRequest ();
+}
+void
+MacHighNqsta::ProbeRequestTimeout (void)
+{
+  TRACE ("probe request timeout");
+  m_state = WAIT_PROBE_RESP;
+  SendProbeRequest ();
+}
+void 
+MacHighNqsta::MissedBeacons (void)
+{
+  m_state = BEACON_MISSED;
+}
+bool
+MacHighNqsta::IsAssociated (void)
+{
+  return (m_state == ASSOCIATED)?true:false;
+}
+
+void 
+MacHighNqsta::Queue (Packet packet, Mac48Address to)
+{
+  if (!IsAssociated ()) 
+    {
+      TryToEnsureAssociated ();
+      return;
+    }
+  //TRACE ("enqueue size="<<packet.GetSize ()<<", to="<<to);
+  WifiMacHeader hdr;
+  hdr.SetTypeData ();
+  hdr.SetAddr1 (GetBssid ());
+  hdr.SetAddr2 (m_interface->GetSelfAddress ());
+  hdr.SetAddr3 (to);
+  hdr.SetDsNotFrom ();
+  hdr.SetDsTo ();
+  m_dca->Queue (packet, hdr);
+}
+
+void 
+MacHighNqsta::Receive (Packet packet, WifiMacHeader const *hdr)
+{
+  NS_ASSERT (!hdr->IsCtl ());
+  if (hdr->GetAddr1 () != m_interface->GetSelfAddress () &&
+      !hdr->GetAddr1 ().IsBroadcast ()) 
+    {
+      // packet is not for us
+    } 
+  else if (hdr->IsData ()) 
+    {
+      m_forward (packet);
+    } 
+  else if (hdr->IsProbeReq () ||
+           hdr->IsAssocReq ()) 
+    {
+      /* this is a frame aimed at an AP.
+       * so we can safely ignore it.
+       */
+    } 
+  else if (hdr->IsBeacon ()) 
+    {
+      MgtBeaconHeader beacon;
+      packet.RemoveHeader (beacon);
+      bool goodBeacon = false;
+      if (m_interface->GetSsid ().IsBroadcast ()) 
+        {
+          // we do not have any special ssid so this
+          // beacon is as good as another.
+          Time delay = MicroSeconds (beacon.GetBeaconIntervalUs () * m_maxMissedBeacons);
+          m_beaconWatchdog.Ping (delay);
+          goodBeacon = true;
+        } 
+      else if (beacon.GetSsid ().IsEqual (m_interface->GetSsid ())) 
+        {
+          //beacon for our ssid.
+          Time delay = MicroSeconds (beacon.GetBeaconIntervalUs () * m_maxMissedBeacons);
+          m_beaconWatchdog.Ping (delay);
+          goodBeacon = true;
+        }
+      if (goodBeacon) 
+        {
+          SetBssid (hdr->GetAddr3 ());
+        }
+    if (goodBeacon && m_state == BEACON_MISSED) 
+      {
+        m_state = WAIT_ASSOC_RESP;
+        SendAssociationRequest ();
+      }
+  } 
+  else if (hdr->IsProbeResp ()) 
+    {
+      if (m_state == WAIT_PROBE_RESP) 
+        {
+          MgtProbeResponseHeader probeResp;
+          packet.RemoveHeader (probeResp);
+          if (!probeResp.GetSsid ().IsEqual (m_interface->GetSsid ())) 
+            {
+              //not a probe resp for our ssid.
+              return;
+            }
+          SetBssid (hdr->GetAddr3 ());
+          Time delay = MicroSeconds (probeResp.GetBeaconIntervalUs () * m_maxMissedBeacons);
+          m_watchdog->Ping (delay);
+          if (m_probeRequestEvent.IsRunning ()) 
+            {
+              m_probeRequestEvent.Cancel ();
+            }
+          m_state = WAIT_ASSOC_RESP;
+          SendAssociationRequest ();
+        }
+    } 
+  else if (hdr->IsAssocResp ()) 
+    {
+      if (m_state == WAIT_ASSOC_RESP) 
+        {
+          MgtAssocResponseHeader assocResp;
+          packet.RemoveHeader (assocResp);
+          if (m_assocRequestEvent.IsRunning ()) 
+            {
+              m_assocRequestEvent.Cancel ();
+            }
+          if (assocResp.GetStatusCode ().IsSuccess ()) 
+            {
+              m_state = ASSOCIATED;
+              TRACE ("assoc completed"); 
+              m_associatedCallback ();
+            } 
+          else 
+            {
+              TRACE ("assoc refused");
+              m_state = REFUSED;
+            }
+        }
+    }
+}
+
+} // namespace ns3
diff --git a/src/devices/wifi/mac-high-nqsta.h b/src/devices/wifi/mac-high-nqsta.h
new file mode 100644
index 000000000..2260d2b9d
--- /dev/null
+++ b/src/devices/wifi/mac-high-nqsta.h
@@ -0,0 +1,103 @@
+/* -*-  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
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
+ */
+#ifndef MAC_HIGH_NQSTA_H
+#define MAC_HIGH_NQSTA_H
+
+#include <stdint.h>
+
+#include "ns3/mac48-address.h"
+#include "ns3/callback.h"
+#include "ns3/event-id.h"
+#include "ns3/packet.h"
+#include "ns3/nstime.h"
+
+#include "supported-rates.h"
+
+namespace ns3 {
+
+class WifiMacHeader;
+class WifiNetDevice;
+class DcaTxop;
+class Watchdog;
+
+class MacHighNqsta {
+public:
+  typedef Callback<void, Packet > ForwardCallback;
+  typedef Callback<void> AssociatedCallback;
+  typedef Callback<void> DisAssociatedCallback;
+
+  MacHighNqsta ();
+  ~MacHighNqsta ();
+
+  void SetDcaTxop (DcaTxop *dca);
+  void SetInterface (WifiNetDevice *interface);
+  void SetForwardCallback (ForwardCallback callback);
+  void SetAssociatedCallback (AssociatedCallback callback);
+  void SetDisAssociatedCallback (DisAssociatedCallback callback);
+  void SetSupportedRates (SupportedRates rates);
+
+  void SetMaxMissedBeacons (uint32_t missed);
+  void SetProbeRequestTimeout (Time timeout);
+  void SetAssocRequestTimeout (Time timeout);
+
+  Mac48Address GetBssid (void) const;
+
+  void StartActiveAssociation (void);
+
+  void Queue (Packet packet, Mac48Address to);
+
+  void Receive (Packet packet, WifiMacHeader const *hdr);
+private:
+  void SetBssid (Mac48Address bssid);
+  Mac48Address GetBroadcastBssid (void);
+  void SendProbeRequest (void);
+  void SendAssociationRequest ();
+  void TryToEnsureAssociated (void);
+  void AssocRequestTimeout (void);
+  void ProbeRequestTimeout (void);
+  bool IsAssociated (void);
+  SupportedRates GetSupportedRates (void);
+  void MissedBeacons (void);
+  enum {
+    ASSOCIATED,
+    WAIT_PROBE_RESP,
+    WAIT_ASSOC_RESP,
+    BEACON_MISSED,
+    REFUSED
+  } m_state;
+  Time m_probeRequestTimeout;
+  Time m_assocRequestTimeout;
+  EventId m_probeRequestEvent;
+  EventId m_assocRequestEvent;
+  WifiNetDevice *m_interface;
+  ForwardCallback m_forward;
+  AssociatedCallback m_associatedCallback;
+  DisAssociatedCallback m_disAssociatedCallback;
+  SupportedRates m_rates;
+  DcaTxop *m_dca;
+  Watchdog *m_beaconWatchdog;
+  Mac48Address m_bssid;
+  uint32_t m_maxMissedBeacons;
+};
+
+} // namespace ns3
+
+
+#endif /* MAC_HIGH_NQSTA_H */
diff --git a/src/devices/wifi/wscript b/src/devices/wifi/wscript
index 138e9f2b1..4cb380b2c 100644
--- a/src/devices/wifi/wscript
+++ b/src/devices/wifi/wscript
@@ -29,6 +29,7 @@ def build(bld):
         'status-code.cc',
         'mgt-headers.cc',
         'mac-high-nqap.cc',
+        'mac-high-nqsta.cc',
         ]
     headers = bld.create_obj('ns3header')
     headers.source = [