wifi-remote-station-manager.cc

Go to the documentation of this file.

/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2005,2006,2007 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 "wifi-remote-station-manager.h"
#include "ns3/simulator.h"
#include "ns3/assert.h"
#include "ns3/log.h"
#include "ns3/tag.h"
#include "ns3/boolean.h"
#include "ns3/double.h"
#include "ns3/uinteger.h"
#include "ns3/wifi-phy.h"
#include "ns3/trace-source-accessor.h"
#include "wifi-mac-header.h"
#include "wifi-mac-trailer.h"

NS_LOG_COMPONENT_DEFINE ("WifiRemoteStationManager");


/***************************************************************
 *           Packet Mode Tagger
 ***************************************************************/

namespace ns3 {

class HighLatencyDataTxVectorTag : public Tag
{
public:
  HighLatencyDataTxVectorTag ();
  HighLatencyDataTxVectorTag (WifiTxVector dataTxVector);
  WifiTxVector GetDataTxVector (void) const;

  static TypeId GetTypeId (void);
  virtual TypeId GetInstanceTypeId (void) const;
  virtual uint32_t GetSerializedSize (void) const;
  virtual void Serialize (TagBuffer i) const;
  virtual void Deserialize (TagBuffer i);
  virtual void Print (std::ostream &os) const;
private:
  WifiTxVector m_dataTxVector;
};

HighLatencyDataTxVectorTag::HighLatencyDataTxVectorTag ()
{
}
HighLatencyDataTxVectorTag::HighLatencyDataTxVectorTag ( WifiTxVector dataTxVector)
  : m_dataTxVector (dataTxVector)
{
}

WifiTxVector 
HighLatencyDataTxVectorTag::GetDataTxVector (void) const
{
  return m_dataTxVector;
}
TypeId
HighLatencyDataTxVectorTag::GetTypeId (void)
{
  static TypeId tid = TypeId ("ns3::HighLatencyDataTxVectorTag")
    .SetParent<Tag> ()
    .AddConstructor<HighLatencyDataTxVectorTag> ()  
    ;
  return tid;
}
TypeId
HighLatencyDataTxVectorTag::GetInstanceTypeId (void) const
{
  return GetTypeId ();
}
uint32_t
HighLatencyDataTxVectorTag::GetSerializedSize (void) const
{
  return sizeof (WifiTxVector);
}
void
HighLatencyDataTxVectorTag::Serialize (TagBuffer i) const
{
  i.Write ((uint8_t *)&m_dataTxVector, sizeof (WifiTxVector));
}
void
HighLatencyDataTxVectorTag::Deserialize (TagBuffer i)
{
  i.Read ((uint8_t *)&m_dataTxVector, sizeof (WifiTxVector));
}
void
HighLatencyDataTxVectorTag::Print (std::ostream &os) const
{
  os << "Data=" << m_dataTxVector;
}

class HighLatencyRtsTxVectorTag : public Tag
{
public:
  HighLatencyRtsTxVectorTag ();
  HighLatencyRtsTxVectorTag (WifiTxVector rtsTxVector);
  WifiTxVector GetRtsTxVector (void) const;

  static TypeId GetTypeId (void);
  virtual TypeId GetInstanceTypeId (void) const;
  virtual uint32_t GetSerializedSize (void) const;
  virtual void Serialize (TagBuffer i) const;
  virtual void Deserialize (TagBuffer i);
  virtual void Print (std::ostream &os) const;
private:
  WifiTxVector m_rtsTxVector;
};

HighLatencyRtsTxVectorTag::HighLatencyRtsTxVectorTag ()
{
}
HighLatencyRtsTxVectorTag::HighLatencyRtsTxVectorTag ( WifiTxVector rtsTxVector)
  : m_rtsTxVector (rtsTxVector)
{
}

WifiTxVector 
HighLatencyRtsTxVectorTag::GetRtsTxVector (void) const
{
  return m_rtsTxVector;
}
TypeId
HighLatencyRtsTxVectorTag::GetTypeId (void)
{
  static TypeId tid = TypeId ("ns3::HighLatencyRtsTxVectorTag")
    .SetParent<Tag> ()
    .AddConstructor<HighLatencyRtsTxVectorTag> ()  
    ;
  return tid;
}
TypeId
HighLatencyRtsTxVectorTag::GetInstanceTypeId (void) const
{
  return GetTypeId ();
}
uint32_t
HighLatencyRtsTxVectorTag::GetSerializedSize (void) const
{
  return sizeof (WifiTxVector);
}
void
HighLatencyRtsTxVectorTag::Serialize (TagBuffer i) const
{
  i.Write ((uint8_t *)&m_rtsTxVector, sizeof (WifiTxVector));
}
void
HighLatencyRtsTxVectorTag::Deserialize (TagBuffer i)
{
  i.Read ((uint8_t *)&m_rtsTxVector, sizeof (WifiTxVector));
}
void
HighLatencyRtsTxVectorTag::Print (std::ostream &os) const
{
  os << "Rts=" << m_rtsTxVector;
}

class HighLatencyCtsToSelfTxVectorTag : public Tag
{
public:
  HighLatencyCtsToSelfTxVectorTag ();
  HighLatencyCtsToSelfTxVectorTag (WifiTxVector ctsToSelfTxVector);
  WifiTxVector GetCtsToSelfTxVector (void) const;

  static TypeId GetTypeId (void);
  virtual TypeId GetInstanceTypeId (void) const;
  virtual uint32_t GetSerializedSize (void) const;
  virtual void Serialize (TagBuffer i) const;
  virtual void Deserialize (TagBuffer i);
  virtual void Print (std::ostream &os) const;
private:
  WifiTxVector m_ctsToSelfTxVector;
};

HighLatencyCtsToSelfTxVectorTag::HighLatencyCtsToSelfTxVectorTag ()
{
}
HighLatencyCtsToSelfTxVectorTag::HighLatencyCtsToSelfTxVectorTag ( WifiTxVector ctsToSelfTxVector)
  : m_ctsToSelfTxVector (ctsToSelfTxVector)
{
}

WifiTxVector 
HighLatencyCtsToSelfTxVectorTag::GetCtsToSelfTxVector (void) const
{
  return m_ctsToSelfTxVector;
}
TypeId
HighLatencyCtsToSelfTxVectorTag::GetTypeId (void)
{
  static TypeId tid = TypeId ("ns3::HighLatencyCtsToSelfTxVectorTag")
    .SetParent<Tag> ()
    .AddConstructor<HighLatencyCtsToSelfTxVectorTag> ()  
    ;
  return tid;
}
TypeId
HighLatencyCtsToSelfTxVectorTag::GetInstanceTypeId (void) const
{
  return GetTypeId ();
}
uint32_t
HighLatencyCtsToSelfTxVectorTag::GetSerializedSize (void) const
{
  return sizeof (WifiTxVector);
}
void
HighLatencyCtsToSelfTxVectorTag::Serialize (TagBuffer i) const
{
  i.Write ((uint8_t *)&m_ctsToSelfTxVector, sizeof (WifiTxVector));
}
void
HighLatencyCtsToSelfTxVectorTag::Deserialize (TagBuffer i)
{
  i.Read ((uint8_t *)&m_ctsToSelfTxVector, sizeof (WifiTxVector));
}
void
HighLatencyCtsToSelfTxVectorTag::Print (std::ostream &os) const
{
  os << "Cts To Self=" << m_ctsToSelfTxVector;
}

} // namespace ns3

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (WifiRemoteStationManager);

TypeId
WifiRemoteStationManager::GetTypeId (void)
{
  static TypeId tid = TypeId ("ns3::WifiRemoteStationManager")
    .SetParent<Object> ()
    .AddAttribute ("IsLowLatency", "If true, we attempt to modelize a so-called low-latency device: a device"
                   " where decisions about tx parameters can be made on a per-packet basis and feedback about the"
                   " transmission of each packet is obtained before sending the next. Otherwise, we modelize a "
                   " high-latency device, that is a device where we cannot update our decision about tx parameters"
                   " after every packet transmission.",
                   BooleanValue (true), // this value is ignored because there is no setter
                   MakeBooleanAccessor (&WifiRemoteStationManager::IsLowLatency),
                   MakeBooleanChecker ())
    .AddAttribute ("MaxSsrc", "The maximum number of retransmission attempts for an RTS. This value"
                   " will not have any effect on some rate control algorithms.",
                   UintegerValue (7),
                   MakeUintegerAccessor (&WifiRemoteStationManager::m_maxSsrc),
                   MakeUintegerChecker<uint32_t> ())
    .AddAttribute ("MaxSlrc", "The maximum number of retransmission attempts for a DATA packet. This value"
                   " will not have any effect on some rate control algorithms.",
                   UintegerValue (7),
                   MakeUintegerAccessor (&WifiRemoteStationManager::m_maxSlrc),
                   MakeUintegerChecker<uint32_t> ())
    .AddAttribute ("RtsCtsThreshold", "If  the size of the data packet + LLC header + MAC header + FCS trailer is bigger than "
                   "this value, we use an RTS/CTS handshake before sending the data, as per IEEE Std. 802.11-2012, Section 9.3.5. "
                   "This value will not have any effect on some rate control algorithms.",
                   UintegerValue (2346),
                   MakeUintegerAccessor (&WifiRemoteStationManager::m_rtsCtsThreshold),
                   MakeUintegerChecker<uint32_t> ())
    .AddAttribute ("FragmentationThreshold", "If the size of the data packet + LLC header + MAC header + FCS trailer is bigger"
                   "than this value, we fragment it such that the size of the fragments are equal or smaller "
                   "than this value, as per IEEE Std. 802.11-2012, Section 9.5. "
                   "This value will not have any effect on some rate control algorithms.",
                   UintegerValue (2346),
                   MakeUintegerAccessor (&WifiRemoteStationManager::DoSetFragmentationThreshold,
                                         &WifiRemoteStationManager::DoGetFragmentationThreshold),
                   MakeUintegerChecker<uint32_t> ())
    .AddAttribute ("NonUnicastMode", "Wifi mode used for non-unicast transmissions.",
                   WifiModeValue (),
                   MakeWifiModeAccessor (&WifiRemoteStationManager::m_nonUnicastMode),
                   MakeWifiModeChecker ())
    .AddAttribute ("DefaultTxPowerLevel", "Default power level to be used for transmissions. "
                   "This is the power level that is used by all those WifiManagers that do not"
                   "implement TX power control.",
                   UintegerValue (0),
                   MakeUintegerAccessor (&WifiRemoteStationManager::m_defaultTxPowerLevel),
                   MakeUintegerChecker<uint8_t> ())
    .AddTraceSource ("MacTxRtsFailed",
                     "The transmission of a RTS by the MAC layer has failed",
                     MakeTraceSourceAccessor (&WifiRemoteStationManager::m_macTxRtsFailed))
    .AddTraceSource ("MacTxDataFailed",
                     "The transmission of a data packet by the MAC layer has failed",
                     MakeTraceSourceAccessor (&WifiRemoteStationManager::m_macTxDataFailed))
    .AddTraceSource ("MacTxFinalRtsFailed",
                     "The transmission of a RTS has exceeded the maximum number of attempts",
                     MakeTraceSourceAccessor (&WifiRemoteStationManager::m_macTxFinalRtsFailed))
    .AddTraceSource ("MacTxFinalDataFailed",
                     "The transmission of a data packet has exceeded the maximum number of attempts",
                     MakeTraceSourceAccessor (&WifiRemoteStationManager::m_macTxFinalDataFailed))
  ;
  return tid;
}

WifiRemoteStationManager::WifiRemoteStationManager ()
{
}

WifiRemoteStationManager::~WifiRemoteStationManager ()
{
}
void
WifiRemoteStationManager::DoDispose (void)
{
  for (StationStates::const_iterator i = m_states.begin (); i != m_states.end (); i++)
    {
      delete (*i);
    }
  m_states.clear ();
  for (Stations::const_iterator i = m_stations.begin (); i != m_stations.end (); i++)
    {
      delete (*i);
    }
  m_stations.clear ();
}
void
WifiRemoteStationManager::SetupPhy (Ptr<WifiPhy> phy)
{
  // We need to track our PHY because it is the object that knows the
  // full set of transmit rates that are supported. We need to know
  // this in order to find the relevant mandatory rates when chosing a
  // transmit rate for automatic control responses like
  // acknowledgements.
  m_wifiPhy = phy;
  m_defaultTxMode = phy->GetMode (0);
  if(HasHtSupported())
    {
       m_defaultTxMcs = phy->GetMcs (0);
    }
  else
    {
      m_defaultTxMcs = 0;
    }
  Reset ();
}
void
WifiRemoteStationManager::SetHtSupported (bool enable)
{
  m_htSupported=enable;
}

bool
WifiRemoteStationManager::HasHtSupported (void) const
{
  return m_htSupported;
}
uint32_t
WifiRemoteStationManager::GetMaxSsrc (void) const
{
  return m_maxSsrc;
}
uint32_t
WifiRemoteStationManager::GetMaxSlrc (void) const
{
  return m_maxSlrc;
}
uint32_t
WifiRemoteStationManager::GetRtsCtsThreshold (void) const
{
  return m_rtsCtsThreshold;
}
uint32_t
WifiRemoteStationManager::GetFragmentationThreshold (void) const
{
  return DoGetFragmentationThreshold ();
}
void
WifiRemoteStationManager::SetMaxSsrc (uint32_t maxSsrc)
{
  m_maxSsrc = maxSsrc;
}
void
WifiRemoteStationManager::SetMaxSlrc (uint32_t maxSlrc)
{
  m_maxSlrc = maxSlrc;
}
void
WifiRemoteStationManager::SetRtsCtsThreshold (uint32_t threshold)
{
  m_rtsCtsThreshold = threshold;
}
void
WifiRemoteStationManager::SetFragmentationThreshold (uint32_t threshold)
{
  DoSetFragmentationThreshold (threshold);
}

void
WifiRemoteStationManager::Reset (Mac48Address address)
{
  NS_ASSERT (!address.IsGroup ());
  WifiRemoteStationState *state = LookupState (address);
  state->m_operationalRateSet.clear ();
  state->m_operationalMcsSet.clear ();
  AddSupportedMode (address, GetDefaultMode ());
  AddSupportedMcs(address,GetDefaultMcs());
}
void
WifiRemoteStationManager::AddSupportedMode (Mac48Address address, WifiMode mode)
{
  NS_ASSERT (!address.IsGroup ());
  WifiRemoteStationState *state = LookupState (address);
  for (WifiModeListIterator i = state->m_operationalRateSet.begin (); i != state->m_operationalRateSet.end (); i++)
    {
      if ((*i) == mode)
        {
          // already in.
          return;
        }
    }
  state->m_operationalRateSet.push_back (mode);
}
/*void
WifiRemoteStationManager::AddBssMembershipParameters(Mac48Address address, uint32_t selector)
{
  NS_ASSERT (!address.IsGroup ());
  WifiRemoteStationState *state = LookupState (address);
  WifiMode mode;
  WifiModeList membershipselectormodes = m_wifiPhy->GetMembershipSelectorModes(selector);
  for (WifiModeListIterator j = membershipselectormodes.begin (); j != membershipselectormodes.end (); j++)
    {
      mode=(*j);
     for (WifiModeListIterator i = state->m_operationalRateSet.begin (); i != state->m_operationalRateSet.end (); i++)
      {
        if ((*i) == mode)
          {
            // already in.
            break;
          }
      }
    state->m_operationalRateSet.push_back (mode);
  }
}*/
void 
WifiRemoteStationManager::AddSupportedMcs (Mac48Address address, uint8_t mcs)
{
  NS_ASSERT (!address.IsGroup ());
  WifiRemoteStationState *state = LookupState (address);
  for (WifiMcsListIterator i = state->m_operationalMcsSet.begin (); i != state->m_operationalMcsSet.end (); i++)
    {
      if ((*i) == mcs)
        {
          // already in.
          return;
        }
    }
  state->m_operationalMcsSet.push_back (mcs);
}
bool
WifiRemoteStationManager::IsBrandNew (Mac48Address address) const
{
  if (address.IsGroup ())
    {
      return false;
    }
  return LookupState (address)->m_state == WifiRemoteStationState::BRAND_NEW;
}
bool
WifiRemoteStationManager::IsAssociated (Mac48Address address) const
{
  if (address.IsGroup ())
    {
      return true;
    }
  return LookupState (address)->m_state == WifiRemoteStationState::GOT_ASSOC_TX_OK;
}
bool
WifiRemoteStationManager::IsWaitAssocTxOk (Mac48Address address) const
{
  if (address.IsGroup ())
    {
      return false;
    }
  return LookupState (address)->m_state == WifiRemoteStationState::WAIT_ASSOC_TX_OK;
}
void
WifiRemoteStationManager::RecordWaitAssocTxOk (Mac48Address address)
{
  NS_ASSERT (!address.IsGroup ());
  LookupState (address)->m_state = WifiRemoteStationState::WAIT_ASSOC_TX_OK;
}
void
WifiRemoteStationManager::RecordGotAssocTxOk (Mac48Address address)
{
  NS_ASSERT (!address.IsGroup ());
  LookupState (address)->m_state = WifiRemoteStationState::GOT_ASSOC_TX_OK;
}
void
WifiRemoteStationManager::RecordGotAssocTxFailed (Mac48Address address)
{
  NS_ASSERT (!address.IsGroup ());
  LookupState (address)->m_state = WifiRemoteStationState::DISASSOC;
}
void
WifiRemoteStationManager::RecordDisassociated (Mac48Address address)
{
  NS_ASSERT (!address.IsGroup ());
  LookupState (address)->m_state = WifiRemoteStationState::DISASSOC;
}
void
WifiRemoteStationManager::PrepareForQueue (Mac48Address address, const WifiMacHeader *header,
                                           Ptr<const Packet> packet, uint32_t fullPacketSize)
{
  if (IsLowLatency () || address.IsGroup ())
    {
      return;
    }
  WifiRemoteStation *station = Lookup (address, header);
  WifiTxVector rts = DoGetRtsTxVector (station);
  WifiTxVector data = DoGetDataTxVector (station, fullPacketSize); 
  WifiTxVector ctstoself = DoGetCtsToSelfTxVector (); 
  HighLatencyDataTxVectorTag datatag;
  HighLatencyRtsTxVectorTag rtstag;
  HighLatencyCtsToSelfTxVectorTag ctstoselftag;
  // first, make sure that the tag is not here anymore.
  ConstCast<Packet> (packet)->RemovePacketTag (datatag);
  ConstCast<Packet> (packet)->RemovePacketTag (rtstag);
  ConstCast<Packet> (packet)->RemovePacketTag (ctstoselftag);
  datatag = HighLatencyDataTxVectorTag (data);
  rtstag = HighLatencyRtsTxVectorTag (rts);
  ctstoselftag = HighLatencyCtsToSelfTxVectorTag (ctstoself);
  // and then, add it back
  packet->AddPacketTag (datatag);
  packet->AddPacketTag (rtstag);
  packet->AddPacketTag (ctstoselftag);
}
WifiTxVector
WifiRemoteStationManager::GetDataTxVector (Mac48Address address, const WifiMacHeader *header,
                                       Ptr<const Packet> packet, uint32_t fullPacketSize)
{
  if (address.IsGroup ())
    {
      WifiTxVector v;
      v.SetMode (GetNonUnicastMode ());
      v.SetTxPowerLevel (m_defaultTxPowerLevel);
      v.SetShortGuardInterval (false);
      v.SetNss (1);
      v.SetNess (0);
      v.SetStbc (false);
      return v;
    }
  if (!IsLowLatency ())
    {
      HighLatencyDataTxVectorTag datatag;
      bool found;
      found = ConstCast<Packet> (packet)->PeekPacketTag (datatag);
      NS_ASSERT (found);
      // cast found to void, to suppress 'found' set but not used
      // compiler warning
      (void) found;
      return datatag.GetDataTxVector ();
    }
  return DoGetDataTxVector (Lookup (address, header), fullPacketSize);
}
WifiTxVector
WifiRemoteStationManager::GetCtsToSelfTxVector(const WifiMacHeader *header,
                                      Ptr<const Packet> packet)
{
  
  if (!IsLowLatency ())
    {
      HighLatencyCtsToSelfTxVectorTag ctstoselftag;
      bool found;
      found = ConstCast<Packet> (packet)->PeekPacketTag (ctstoselftag);
      NS_ASSERT (found);
      // cast found to void, to suppress 'found' set but not used
      // compiler warning
      (void) found;
      return ctstoselftag.GetCtsToSelfTxVector ();
    }
  return DoGetCtsToSelfTxVector ();
}

WifiTxVector
WifiRemoteStationManager::DoGetCtsToSelfTxVector (void)
{
  return WifiTxVector (GetDefaultMode(), GetDefaultTxPowerLevel (),0,m_wifiPhy->GetGuardInterval(),GetNumberOfTransmitAntennas(), GetNumberOfTransmitAntennas(), false);
}

WifiTxVector
WifiRemoteStationManager::GetRtsTxVector (Mac48Address address, const WifiMacHeader *header,
                                      Ptr<const Packet> packet)
{
  NS_ASSERT (!address.IsGroup ());
  if (!IsLowLatency ())
    {
      HighLatencyRtsTxVectorTag rtstag;
      bool found;
      found = ConstCast<Packet> (packet)->PeekPacketTag (rtstag);
      NS_ASSERT (found);
      // cast found to void, to suppress 'found' set but not used
      // compiler warning
      (void) found;
      return rtstag.GetRtsTxVector ();
    }
  return DoGetRtsTxVector (Lookup (address, header));
}
void
WifiRemoteStationManager::ReportRtsFailed (Mac48Address address, const WifiMacHeader *header)
{
  NS_ASSERT (!address.IsGroup ());
  WifiRemoteStation *station = Lookup (address, header);
  station->m_ssrc++;
  m_macTxRtsFailed (address);
  DoReportRtsFailed (station);
}
void
WifiRemoteStationManager::ReportDataFailed (Mac48Address address, const WifiMacHeader *header)
{
  NS_ASSERT (!address.IsGroup ());
  WifiRemoteStation *station = Lookup (address, header);
  station->m_slrc++;
  m_macTxDataFailed (address);
  DoReportDataFailed (station);
}
void
WifiRemoteStationManager::ReportRtsOk (Mac48Address address, const WifiMacHeader *header,
                                       double ctsSnr, WifiMode ctsMode, double rtsSnr)
{
  NS_ASSERT (!address.IsGroup ());
  WifiRemoteStation *station = Lookup (address, header);
  station->m_state->m_info.NotifyTxSuccess (station->m_ssrc);
  station->m_ssrc = 0;
  DoReportRtsOk (station, ctsSnr, ctsMode, rtsSnr);
}
void
WifiRemoteStationManager::ReportDataOk (Mac48Address address, const WifiMacHeader *header,
                                        double ackSnr, WifiMode ackMode, double dataSnr)
{
  NS_ASSERT (!address.IsGroup ());
  WifiRemoteStation *station = Lookup (address, header);
  station->m_state->m_info.NotifyTxSuccess (station->m_slrc);
  station->m_slrc = 0;
  DoReportDataOk (station, ackSnr, ackMode, dataSnr);
}
void
WifiRemoteStationManager::ReportFinalRtsFailed (Mac48Address address, const WifiMacHeader *header)
{
  NS_ASSERT (!address.IsGroup ());
  WifiRemoteStation *station = Lookup (address, header);
  station->m_state->m_info.NotifyTxFailed ();
  station->m_ssrc = 0;
  m_macTxFinalRtsFailed (address);
  DoReportFinalRtsFailed (station);
}
void
WifiRemoteStationManager::ReportFinalDataFailed (Mac48Address address, const WifiMacHeader *header)
{
  NS_ASSERT (!address.IsGroup ());
  WifiRemoteStation *station = Lookup (address, header);
  station->m_state->m_info.NotifyTxFailed ();
  station->m_slrc = 0;
  m_macTxFinalDataFailed (address);
  DoReportFinalDataFailed (station);
}
void
WifiRemoteStationManager::ReportRxOk (Mac48Address address, const WifiMacHeader *header,
                                      double rxSnr, WifiMode txMode)
{
  if (address.IsGroup ())
    {
      return;
    }
  WifiRemoteStation *station = Lookup (address, header);
  DoReportRxOk (station, rxSnr, txMode);
}
bool
WifiRemoteStationManager::NeedRts (Mac48Address address, const WifiMacHeader *header,
                                   Ptr<const Packet> packet)
{
  if (address.IsGroup ())
    {
      return false;
    }
  bool normally = (packet->GetSize () + header->GetSize () + WIFI_MAC_FCS_LENGTH) > GetRtsCtsThreshold ();
  return DoNeedRts (Lookup (address, header), packet, normally);
}
bool
WifiRemoteStationManager::NeedCtsToSelf (WifiTxVector txVector)
{
  WifiMode mode = txVector.GetMode();
 
  // search the BSS Basic Rate set if the used mode in the basic set then no need for Cts to self
  for (WifiModeListIterator i = m_bssBasicRateSet.begin ();
       i != m_bssBasicRateSet.end (); i++)
    {
      if (mode == *i)
        {
          return false;
        }
    }
  if (HasHtSupported())
    {
      uint8_t mcs = m_wifiPhy->WifiModeToMcs (mode);
      for (WifiMcsListIterator i = m_bssBasicMcsSet.begin ();
           i != m_bssBasicMcsSet.end (); i++)
        {
          if (mcs == *i)
            {
              return false;
            }
        }
    }
  return true;
}
bool
WifiRemoteStationManager::NeedRtsRetransmission (Mac48Address address, const WifiMacHeader *header,
                                                 Ptr<const Packet> packet)
{
  NS_ASSERT (!address.IsGroup ());
  WifiRemoteStation *station = Lookup (address, header);
  bool normally = station->m_ssrc < GetMaxSsrc ();
  return DoNeedRtsRetransmission (station, packet, normally);
}
bool
WifiRemoteStationManager::NeedDataRetransmission (Mac48Address address, const WifiMacHeader *header,
                                                  Ptr<const Packet> packet)
{
  NS_ASSERT (!address.IsGroup ());
  WifiRemoteStation *station = Lookup (address, header);
  bool normally = station->m_slrc < GetMaxSlrc ();
  return DoNeedDataRetransmission (station, packet, normally);
}
bool
WifiRemoteStationManager::NeedFragmentation (Mac48Address address, const WifiMacHeader *header,
                                             Ptr<const Packet> packet)
{
  if (address.IsGroup ())
    {
      return false;
    }
  WifiRemoteStation *station = Lookup (address, header);
  bool normally = (packet->GetSize () + header->GetSize () + WIFI_MAC_FCS_LENGTH) > GetFragmentationThreshold ();
  return DoNeedFragmentation (station, packet, normally);
}

void
WifiRemoteStationManager::DoSetFragmentationThreshold (uint32_t threshold)
{
  if (threshold < 256)
    {
      /*
       * ASN.1 encoding of the MAC and PHY MIB (256 ... 8000)
       */
      NS_LOG_WARN ("Fragmentation threshold should be larger than 256. Setting to 256.");
      m_fragmentationThreshold = 256;
    }
  else
    {
      /*
       * The length of each fragment shall be an even number of octets, except for the last fragment if an MSDU or
       * MMPDU, which may be either an even or an odd number of octets.
       */
      if (threshold % 2 != 0)
        {
          NS_LOG_WARN ("Fragmentation threshold should be an even number. Setting to " << threshold - 1);
          m_fragmentationThreshold = threshold - 1; 
        }
      else
        {
          m_fragmentationThreshold = threshold;
        }
    }
}

uint32_t
WifiRemoteStationManager::DoGetFragmentationThreshold (void) const
{
  return m_fragmentationThreshold;
}

uint32_t
WifiRemoteStationManager::GetNFragments (const WifiMacHeader *header, Ptr<const Packet> packet)
{
  //The number of bytes a fragment can support is (Threshold - WIFI_HEADER_SIZE - WIFI_FCS).
  uint32_t nFragments = (packet->GetSize () / (GetFragmentationThreshold () - header->GetSize () - WIFI_MAC_FCS_LENGTH));

  //If the size of the last fragment is not 0.
  if ((packet->GetSize () % (GetFragmentationThreshold () - header->GetSize () - WIFI_MAC_FCS_LENGTH)) > 0)
    {
      nFragments++;
    }
  return nFragments;
}

uint32_t
WifiRemoteStationManager::GetFragmentSize (Mac48Address address, const WifiMacHeader *header,
                                           Ptr<const Packet> packet, uint32_t fragmentNumber)
{
  NS_ASSERT (!address.IsGroup ());
  uint32_t nFragment = GetNFragments (header, packet);
  if (fragmentNumber >= nFragment)
    {
      return 0;
    }
  //Last fragment
  if (fragmentNumber == nFragment - 1)
    {
      uint32_t lastFragmentSize = packet->GetSize () - (fragmentNumber * (GetFragmentationThreshold () - header->GetSize () - WIFI_MAC_FCS_LENGTH));
      return lastFragmentSize;
    }
  //All fragments but the last, the number of bytes is (Threshold - WIFI_HEADER_SIZE - WIFI_FCS).
  else
    {
      return GetFragmentationThreshold () - header->GetSize () - WIFI_MAC_FCS_LENGTH;
    }
}
uint32_t
WifiRemoteStationManager::GetFragmentOffset (Mac48Address address, const WifiMacHeader *header,
                                             Ptr<const Packet> packet, uint32_t fragmentNumber)
{
  NS_ASSERT (!address.IsGroup ());
  NS_ASSERT (fragmentNumber < GetNFragments (header, packet));
  uint32_t fragmentOffset = fragmentNumber * (GetFragmentationThreshold () - header->GetSize () - WIFI_MAC_FCS_LENGTH);
  return fragmentOffset;
}
bool
WifiRemoteStationManager::IsLastFragment (Mac48Address address, const WifiMacHeader *header,
                                          Ptr<const Packet> packet, uint32_t fragmentNumber)
{
  NS_ASSERT (!address.IsGroup ());
  bool isLast = fragmentNumber == (GetNFragments (header, packet) - 1);
  return isLast;
}
WifiMode
WifiRemoteStationManager::GetControlAnswerMode (Mac48Address address, WifiMode reqMode)
{
  WifiMode mode = GetDefaultMode ();
  bool found = false;

  // First, search the BSS Basic Rate set
  for (WifiModeListIterator i = m_bssBasicRateSet.begin ();
       i != m_bssBasicRateSet.end (); i++)
    {
      if ((!found || i->GetPhyRate () > mode.GetPhyRate ())
          && i->GetPhyRate () <= reqMode.GetPhyRate ()
          && i->GetModulationClass () == reqMode.GetModulationClass ())
        {
          mode = *i;
          // We've found a potentially-suitable transmit rate, but we
          // need to continue and consider all the basic rates before
          // we can be sure we've got the right one.
          found = true;
        }
    }
  if(HasHtSupported())
      {
        if (!found)
          {
            uint8_t mcs = GetDefaultMcs (); 
            mode=  m_wifiPhy->McsToWifiMode (mcs); 
          }
        for (WifiMcsListIterator i = m_bssBasicMcsSet.begin ();
             i != m_bssBasicMcsSet.end (); i++)
          {
            WifiMode thismode=  m_wifiPhy->McsToWifiMode (*i); 
            if ((!found || thismode.GetPhyRate () > mode.GetPhyRate ())
                && thismode.GetPhyRate () <= reqMode.GetPhyRate ()
                && thismode.GetModulationClass () == reqMode.GetModulationClass ())
              {
                mode = thismode;
                // We've found a potentially-suitable transmit rate, but we
                // need to continue and consider all the basic rates before
                // we can be sure we've got the right one.
                found = true;
              }
          }
      }
  // If we found a suitable rate in the BSSBasicRateSet, then we are
  // done and can return that mode.
  if (found)
    {
      return mode;
    }

  for (uint32_t idx = 0; idx < m_wifiPhy->GetNModes (); idx++)
    {
      WifiMode thismode = m_wifiPhy->GetMode (idx);

      /* If the rate:
       *
       *  - is a mandatory rate for the PHY, and
       *  - is equal to or faster than our current best choice, and
       *  - is less than or equal to the rate of the received frame, and
       *  - is of the same modulation class as the received frame
       *
       * ...then it's our best choice so far.
       */
      if (thismode.IsMandatory ()
          && (!found || thismode.GetPhyRate () > mode.GetPhyRate ())
          && thismode.GetPhyRate () <= reqMode.GetPhyRate ()
          && thismode.GetModulationClass () == reqMode.GetModulationClass ())
        {
          mode = thismode;
          // As above; we've found a potentially-suitable transmit
          // rate, but we need to continue and consider all the
          // mandatory rates before we can be sure we've got the right
          // one.
          found = true;
        }
    }
  if(HasHtSupported())
    {
      for (uint32_t idx = 0; idx < m_wifiPhy->GetNMcs (); idx++)
        {
          uint8_t thismcs = m_wifiPhy->GetMcs (idx);
          WifiMode thismode=  m_wifiPhy->McsToWifiMode (thismcs);
          if (thismode.IsMandatory ()
              && (!found || thismode.GetPhyRate () > mode.GetPhyRate ())
              && thismode.GetPhyRate () <= reqMode.GetPhyRate ()
              && thismode.GetModulationClass () == reqMode.GetModulationClass ())
            {
              mode = thismode;
              // As above; we've found a potentially-suitable transmit
              // rate, but we need to continue and consider all the
              // mandatory rates before we can be sure we've got the right
              // one.
              found = true;
            }
            
        }
    }

  if (!found)
    {
      NS_FATAL_ERROR ("Can't find response rate for " << reqMode
                      << ". Check standard and selected rates match.");
    }

  return mode;
}

WifiTxVector
WifiRemoteStationManager::GetCtsTxVector (Mac48Address address, WifiMode rtsMode)
{
  NS_ASSERT (!address.IsGroup ());
  WifiTxVector v;
  v.SetMode (GetControlAnswerMode (address, rtsMode));
  v.SetTxPowerLevel (DoGetCtsTxPowerLevel (address, v.GetMode()));
  v.SetShortGuardInterval (DoGetCtsTxGuardInterval(address, v.GetMode()));
  v.SetNss (DoGetCtsTxNss(address, v.GetMode()));
  v.SetNess (DoGetCtsTxNess(address, v.GetMode()));
  v.SetStbc (DoGetCtsTxStbc(address, v.GetMode()));
  return v;
}
WifiTxVector
WifiRemoteStationManager::GetAckTxVector (Mac48Address address, WifiMode dataMode)
{
  NS_ASSERT (!address.IsGroup ());
  WifiTxVector v;
  v.SetMode (GetControlAnswerMode (address, dataMode));
  v.SetTxPowerLevel (DoGetAckTxPowerLevel (address, v.GetMode()));
  v.SetShortGuardInterval(DoGetAckTxGuardInterval(address, v.GetMode()));
  v.SetNss(DoGetAckTxNss(address, v.GetMode()));
  v.SetNess(DoGetAckTxNess(address, v.GetMode()));
  v.SetStbc(DoGetAckTxStbc(address, v.GetMode()));
  return v;
}
WifiTxVector
WifiRemoteStationManager::GetBlockAckTxVector (Mac48Address address, WifiMode blockAckReqMode)
{
  NS_ASSERT (!address.IsGroup ());
  WifiTxVector v;
  v.SetMode (GetControlAnswerMode (address, blockAckReqMode));
  v.SetTxPowerLevel (DoGetBlockAckTxPowerLevel (address, v.GetMode()));
  v.SetShortGuardInterval (DoGetBlockAckTxGuardInterval(address, v.GetMode()));
  v.SetNss (DoGetBlockAckTxNss(address, v.GetMode()));
  v.SetNess (DoGetBlockAckTxNess(address, v.GetMode()));
  v.SetStbc (DoGetBlockAckTxStbc(address, v.GetMode()));
  return v;
}

uint8_t 
WifiRemoteStationManager::DoGetCtsTxPowerLevel (Mac48Address address, WifiMode ctsMode)
{
  return m_defaultTxPowerLevel;
}

bool 
WifiRemoteStationManager::DoGetCtsTxGuardInterval(Mac48Address address, WifiMode ctsMode)
{
  return m_wifiPhy->GetGuardInterval();
}

uint8_t
WifiRemoteStationManager::DoGetCtsTxNss(Mac48Address address, WifiMode ctsMode)
{
  return 1;
}
uint8_t
WifiRemoteStationManager::DoGetCtsTxNess(Mac48Address address, WifiMode ctsMode)
{
  return 0;
}
bool 
WifiRemoteStationManager::DoGetCtsTxStbc(Mac48Address address, WifiMode ctsMode)
{
  return m_wifiPhy->GetStbc();
}

uint8_t 
WifiRemoteStationManager::DoGetAckTxPowerLevel (Mac48Address address, WifiMode ackMode)
{
  return m_defaultTxPowerLevel;
}

bool 
WifiRemoteStationManager::DoGetAckTxGuardInterval(Mac48Address address, WifiMode ackMode)
{
  return m_wifiPhy->GetGuardInterval();
}

uint8_t
WifiRemoteStationManager::DoGetAckTxNss(Mac48Address address, WifiMode ackMode)
{
  return 1;
}
uint8_t
WifiRemoteStationManager::DoGetAckTxNess(Mac48Address address, WifiMode ackMode)
{
  return 0;
}
bool 
WifiRemoteStationManager::DoGetAckTxStbc(Mac48Address address, WifiMode ackMode)
{
  return m_wifiPhy->GetStbc();
}

uint8_t 
WifiRemoteStationManager::DoGetBlockAckTxPowerLevel (Mac48Address address, WifiMode blockAckMode)
{
  return m_defaultTxPowerLevel;
}

bool 
WifiRemoteStationManager::DoGetBlockAckTxGuardInterval(Mac48Address address, WifiMode blockAckMode)
{
  return m_wifiPhy->GetGuardInterval();
}

uint8_t
WifiRemoteStationManager::DoGetBlockAckTxNss(Mac48Address address, WifiMode blockAckMode)
{
  return 1;
}
uint8_t
WifiRemoteStationManager::DoGetBlockAckTxNess(Mac48Address address, WifiMode blockAckMode)
{
  return 0;
}
bool 
WifiRemoteStationManager::DoGetBlockAckTxStbc(Mac48Address address, WifiMode blockAckMode)
{
  return m_wifiPhy->GetStbc();
}


uint8_t
WifiRemoteStationManager::GetDefaultTxPowerLevel (void) const
{
  return m_defaultTxPowerLevel;
}


WifiRemoteStationInfo
WifiRemoteStationManager::GetInfo (Mac48Address address)
{
  WifiRemoteStationState *state = LookupState (address);
  return state->m_info;
}

WifiRemoteStationState *
WifiRemoteStationManager::LookupState (Mac48Address address) const
{
  for (StationStates::const_iterator i = m_states.begin (); i != m_states.end (); i++)
    {
      if ((*i)->m_address == address)
        {
          return (*i);
        }
    }
  WifiRemoteStationState *state = new WifiRemoteStationState ();
  state->m_state = WifiRemoteStationState::BRAND_NEW;
  state->m_address = address;
  state->m_operationalRateSet.push_back (GetDefaultMode ());
  state->m_operationalMcsSet.push_back(GetDefaultMcs());
  state->m_shortGuardInterval=m_wifiPhy->GetGuardInterval();
  state->m_greenfield=m_wifiPhy->GetGreenfield();
  state->m_rx=1;
  state->m_tx=1;
  state->m_stbc=false;
  const_cast<WifiRemoteStationManager *> (this)->m_states.push_back (state);
  return state;
}
WifiRemoteStation *
WifiRemoteStationManager::Lookup (Mac48Address address, const WifiMacHeader *header) const
{
  uint8_t tid;
  if (header->IsQosData ())
    {
      tid = header->GetQosTid ();
    }
  else
    {
      tid = 0;
    }
  return Lookup (address, tid);
}
WifiRemoteStation *
WifiRemoteStationManager::Lookup (Mac48Address address, uint8_t tid) const
{
  for (Stations::const_iterator i = m_stations.begin (); i != m_stations.end (); i++)
    {
      if ((*i)->m_tid == tid
          && (*i)->m_state->m_address == address)
        {
          return (*i);
        }
    }
  WifiRemoteStationState *state = LookupState (address);

  WifiRemoteStation *station = DoCreateStation ();
  station->m_state = state;
  station->m_tid = tid;
  station->m_ssrc = 0;
  station->m_slrc = 0;
  // XXX
  const_cast<WifiRemoteStationManager *> (this)->m_stations.push_back (station);
  return station;

}
//Used by all stations to record HT capabilities of remote stations
void
WifiRemoteStationManager::AddStationHtCapabilities (Mac48Address from, HtCapabilities htcapabilities)
{
  WifiRemoteStationState *state;
  state=LookupState (from);
  state->m_shortGuardInterval=htcapabilities.GetShortGuardInterval20();
  state->m_greenfield=htcapabilities.GetGreenfield();
 
}
//Used by mac low to choose format used GF, MF or Non HT
bool 
WifiRemoteStationManager::GetGreenfieldSupported (Mac48Address address) const
{
 return LookupState(address)->m_greenfield;
}
WifiMode
WifiRemoteStationManager::GetDefaultMode (void) const
{
  return m_defaultTxMode;
}
uint8_t
WifiRemoteStationManager::GetDefaultMcs (void) const
{
  return m_defaultTxMcs;
}
void
WifiRemoteStationManager::Reset (void)
{
  for (Stations::const_iterator i = m_stations.begin (); i != m_stations.end (); i++)
    {
      delete (*i);
    }
  m_stations.clear ();
  m_bssBasicRateSet.clear ();
  m_bssBasicRateSet.push_back (m_defaultTxMode);
  m_bssBasicMcsSet.clear();
  m_bssBasicMcsSet.push_back (m_defaultTxMcs);
  NS_ASSERT (m_defaultTxMode.IsMandatory ());
}
void
WifiRemoteStationManager::AddBasicMode (WifiMode mode)
{
  for (uint32_t i = 0; i < GetNBasicModes (); i++)
    {
      if (GetBasicMode (i) == mode)
        {
          return;
        }
    }
  m_bssBasicRateSet.push_back (mode);
}
uint32_t
WifiRemoteStationManager::GetNBasicModes (void) const
{
  return m_bssBasicRateSet.size ();
}
WifiMode
WifiRemoteStationManager::GetBasicMode (uint32_t i) const
{
  NS_ASSERT (i < m_bssBasicRateSet.size ());
  return m_bssBasicRateSet[i];
}

void 
WifiRemoteStationManager::AddBasicMcs (uint8_t mcs)
{
   for (uint32_t i = 0; i < GetNBasicMcs (); i++)
    {
      if (GetBasicMcs (i) == mcs)
        {
          return;
        }
    }
  m_bssBasicMcsSet.push_back (mcs);
}

uint32_t
WifiRemoteStationManager::GetNBasicMcs (void) const
{
  return m_bssBasicMcsSet.size ();
}
uint8_t 
WifiRemoteStationManager::GetBasicMcs (uint32_t i) const
{
   NS_ASSERT (i < m_bssBasicMcsSet.size ());
  return m_bssBasicMcsSet[i];
}

WifiMode
WifiRemoteStationManager::GetNonUnicastMode (void) const
{
  if (m_nonUnicastMode == WifiMode ())
    {
      return GetBasicMode (0);
    }
  else
    {
      return m_nonUnicastMode;
    }
}

bool
WifiRemoteStationManager::DoNeedRts (WifiRemoteStation *station,
                                     Ptr<const Packet> packet, bool normally)
{
  return normally;
}
bool
WifiRemoteStationManager::DoNeedRtsRetransmission (WifiRemoteStation *station,
                                                   Ptr<const Packet> packet, bool normally)
{
  return normally;
}
bool
WifiRemoteStationManager::DoNeedDataRetransmission (WifiRemoteStation *station,
                                                    Ptr<const Packet> packet, bool normally)
{
  return normally;
}
bool
WifiRemoteStationManager::DoNeedFragmentation (WifiRemoteStation *station,
                                               Ptr<const Packet> packet, bool normally)
{
  return normally;
}

WifiMode
WifiRemoteStationManager::GetSupported (const WifiRemoteStation *station, uint32_t i) const
{
  NS_ASSERT (i < GetNSupported (station));
  return station->m_state->m_operationalRateSet[i];
}
uint8_t
WifiRemoteStationManager::GetMcsSupported (const WifiRemoteStation *station, uint32_t i) const
{
  NS_ASSERT (i < GetNMcsSupported (station));
  return station->m_state->m_operationalMcsSet[i];
}
bool 
WifiRemoteStationManager::GetShortGuardInterval (const WifiRemoteStation *station) const
{
  return station->m_state->m_shortGuardInterval;
}
bool 
WifiRemoteStationManager::GetGreenfield (const WifiRemoteStation *station) const
{
  return station->m_state->m_greenfield;
}
bool 
WifiRemoteStationManager::GetStbc (const WifiRemoteStation *station) const
{
  return station->m_state->m_stbc;
}
uint32_t 
WifiRemoteStationManager::GetNumberOfReceiveAntennas (const WifiRemoteStation *station) const
{
  return station->m_state->m_rx;
}
uint32_t 
WifiRemoteStationManager::GetNumberOfTransmitAntennas (const WifiRemoteStation *station) const
{
  return station->m_state->m_tx;
}
uint32_t 
WifiRemoteStationManager::GetShortRetryCount (const WifiRemoteStation *station) const
{
  return station->m_ssrc;
}
uint32_t 
WifiRemoteStationManager::GetLongRetryCount (const WifiRemoteStation *station) const
{
  return station->m_slrc;
}
uint32_t
WifiRemoteStationManager::GetNSupported (const WifiRemoteStation *station) const
{
  return station->m_state->m_operationalRateSet.size ();
}
uint32_t
WifiRemoteStationManager::GetNMcsSupported (const WifiRemoteStation *station) const
{
  return station->m_state->m_operationalMcsSet.size ();
}
void
WifiRemoteStationManager::SetDefaultTxPowerLevel (uint8_t txPower)
{
  m_defaultTxPowerLevel = txPower;
}

//support 11n
uint32_t
WifiRemoteStationManager::GetNumberOfTransmitAntennas (void)
{
  return m_wifiPhy->GetNumberOfTransmitAntennas();
}
//WifiRemoteStationInfo constructor
WifiRemoteStationInfo::WifiRemoteStationInfo ()
  : m_memoryTime (Seconds (1.0)),
    m_lastUpdate (Seconds (0.0)),
    m_failAvg (0.0)
{
}

double
WifiRemoteStationInfo::CalculateAveragingCoefficient ()
{
  double retval = std::exp ((double)(m_lastUpdate.GetMicroSeconds () - Simulator::Now ().GetMicroSeconds ())
                            / (double)m_memoryTime.GetMicroSeconds ());
  m_lastUpdate = Simulator::Now ();
  return retval;
}

void
WifiRemoteStationInfo::NotifyTxSuccess (uint32_t retryCounter)
{
  double coefficient = CalculateAveragingCoefficient ();
  m_failAvg = (double)retryCounter / (1 + (double) retryCounter) * (1.0 - coefficient) + coefficient * m_failAvg;
}

void
WifiRemoteStationInfo::NotifyTxFailed ()
{
  double coefficient = CalculateAveragingCoefficient ();
  m_failAvg = (1.0 - coefficient) + coefficient * m_failAvg;
}

double
WifiRemoteStationInfo::GetFrameErrorRate () const
{
  return m_failAvg;
}
} // namespace ns3