/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */

/*

 * Copyright (c) 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 "ideal-wifi-manager.h"

#include "wifi-phy.h"

#include "ns3/assert.h"

#include "ns3/double.h"

#include <cmath>

#define Min(a,b) ((a < b) ? a : b)

namespace ns3 {

struct IdealWifiRemoteStation : public WifiRemoteStation

{

  double m_lastSnr;

};

TypeId

IdealWifiManager::GetTypeId (void)

{

  static TypeId tid = TypeId ("ns3::IdealWifiManager")

    .SetParent<WifiRemoteStationManager> ()

    .AddConstructor<IdealWifiManager> ()

    .AddAttribute ("BerThreshold",

                   "The maximum Bit Error Rate acceptable at any transmission mode",

                   DoubleValue (10e-6),

                   MakeDoubleAccessor (&IdealWifiManager::m_ber),

                   MakeDoubleChecker<double> ())

  ;

  return tid;

}

IdealWifiManager::IdealWifiManager ()

{

}

IdealWifiManager::~IdealWifiManager ()

{

}

void

IdealWifiManager::SetupPhy (Ptr<WifiPhy> phy)

{

  uint32_t nModes = phy->GetNModes ();

  for (uint32_t i = 0; i < nModes; i++)

    {

      WifiMode mode = phy->GetMode (i);

      AddModeSnrThreshold (mode, phy->CalculateSnr (mode, m_ber));

    }

  WifiRemoteStationManager::SetupPhy (phy);

}

double

IdealWifiManager::GetSnrThreshold (WifiMode mode) const

{

  for (Thresholds::const_iterator i = m_thresholds.begin (); i != m_thresholds.end (); i++)

    {

      if (mode == i->second)

        {

          return i->first;

        }

    }

  NS_ASSERT (false);

  return 0.0;

}

void

IdealWifiManager::AddModeSnrThreshold (WifiMode mode, double snr)

{

  m_thresholds.push_back (std::make_pair (snr,mode));

}

WifiRemoteStation *

IdealWifiManager::DoCreateStation (void) const

{

  IdealWifiRemoteStation *station = new IdealWifiRemoteStation ();

  station->m_lastSnr = 0.0;

  return station;

}

void

IdealWifiManager::DoReportRxOk (WifiRemoteStation *station,

                                double rxSnr, WifiMode txMode)

{

}

void

IdealWifiManager::DoReportRtsFailed (WifiRemoteStation *station)

{

}

void

IdealWifiManager::DoReportDataFailed (WifiRemoteStation *station)

{

}

void

IdealWifiManager::DoReportRtsOk (WifiRemoteStation *st,

                                 double ctsSnr, WifiMode ctsMode, double rtsSnr)

{

  IdealWifiRemoteStation *station = (IdealWifiRemoteStation *)st;

  station->m_lastSnr = rtsSnr;

}

void

IdealWifiManager::DoReportDataOk (WifiRemoteStation *st,

                                  double ackSnr, WifiMode ackMode, double dataSnr)

{

  IdealWifiRemoteStation *station = (IdealWifiRemoteStation *)st;

  station->m_lastSnr = dataSnr;

}

void

IdealWifiManager::DoReportFinalRtsFailed (WifiRemoteStation *station)

{

}

void

IdealWifiManager::DoReportFinalDataFailed (WifiRemoteStation *station)

{

}

WifiTxVector

IdealWifiManager::DoGetDataTxVector (WifiRemoteStation *st, uint32_t size)

{

  IdealWifiRemoteStation *station = (IdealWifiRemoteStation *)st;

  // We search within the Supported rate set the mode with the

  // highest snr threshold possible which is smaller than m_lastSnr

  // to ensure correct packet delivery.

  double maxThreshold = 0.0;

  WifiMode maxMode = GetDefaultMode ();

  for (uint32_t i = 0; i < GetNSupported (station); i++)

    {

      WifiMode mode = GetSupported (station, i);

      double threshold = GetSnrThreshold (mode);

      if (threshold > maxThreshold

          && threshold < station->m_lastSnr)

        {

          maxThreshold = threshold;

          maxMode = mode;

        }

    }

  return WifiTxVector (maxMode, GetDefaultTxPowerLevel (), GetLongRetryCount (station), GetShortGuardInterval (station), Min (GetNumberOfReceiveAntennas (station),GetNumberOfTransmitAntennas()), GetNumberOfTransmitAntennas (station), GetStbc (station));

}

WifiTxVector

IdealWifiManager::DoGetRtsTxVector (WifiRemoteStation *st)

{

  IdealWifiRemoteStation *station = (IdealWifiRemoteStation *)st;

  // We search within the Basic rate set the mode with the highest

  // snr threshold possible which is smaller than m_lastSnr to

  // ensure correct packet delivery.

  double maxThreshold = 0.0;

  WifiMode maxMode = GetDefaultMode ();

  for (uint32_t i = 0; i < GetNBasicModes (); i++)

    {

      WifiMode mode = GetBasicMode (i);

      double threshold = GetSnrThreshold (mode);

      if (threshold > maxThreshold

          && threshold < station->m_lastSnr)

        {

          maxThreshold = threshold;

          maxMode = mode;

        }

    }

  return WifiTxVector (maxMode, GetDefaultTxPowerLevel (), GetShortRetryCount (station), GetShortGuardInterval (station), Min (GetNumberOfReceiveAntennas (station),GetNumberOfTransmitAntennas()), GetNumberOfTransmitAntennas (station), GetStbc (station));

}

bool

IdealWifiManager::IsLowLatency (void) const

{

  return true;

}

} // namespace ns3