/* -*- 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 "wifi-phy.h"

#include "wifi-mode.h"

#include "wifi-channel.h"

#include "wifi-preamble.h"

#include "ns3/simulator.h"

#include "ns3/packet.h"

#include "ns3/assert.h"

#include "ns3/log.h"

#include "ns3/double.h"

#include "ns3/uinteger.h"

#include "ns3/enum.h"

#include "ns3/trace-source-accessor.h"

#include <cmath>

NS_LOG_COMPONENT_DEFINE ("WifiPhy");

namespace ns3 {

/****************************************************************

 *       This destructor is needed.

 ****************************************************************/

WifiPhyListener::~WifiPhyListener ()

{

}

/****************************************************************

 *       The actual WifiPhy class

 ****************************************************************/

NS_OBJECT_ENSURE_REGISTERED (WifiPhy)

  ;

TypeId

WifiPhy::GetTypeId (void)

{

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

    .SetParent<Object> ()

    .AddTraceSource ("PhyTxBegin",

                     "Trace source indicating a packet has begun transmitting over the channel medium",

                     MakeTraceSourceAccessor (&WifiPhy::m_phyTxBeginTrace))

    .AddTraceSource ("PhyTxEnd",

                     "Trace source indicating a packet has been completely transmitted over the channel. NOTE: the only official WifiPhy implementation available to this date (YansWifiPhy) never fires this trace source.",

                     MakeTraceSourceAccessor (&WifiPhy::m_phyTxEndTrace))

    .AddTraceSource ("PhyTxDrop",

                     "Trace source indicating a packet has been dropped by the device during transmission",

                     MakeTraceSourceAccessor (&WifiPhy::m_phyTxDropTrace))

    .AddTraceSource ("PhyRxBegin",

                     "Trace source indicating a packet has begun being received from the channel medium by the device",

                     MakeTraceSourceAccessor (&WifiPhy::m_phyRxBeginTrace))

    .AddTraceSource ("PhyRxEnd",

                     "Trace source indicating a packet has been completely received from the channel medium by the device",

                     MakeTraceSourceAccessor (&WifiPhy::m_phyRxEndTrace))

    .AddTraceSource ("PhyRxDrop",

                     "Trace source indicating a packet has been dropped by the device during reception",

                     MakeTraceSourceAccessor (&WifiPhy::m_phyRxDropTrace))

    .AddTraceSource ("MonitorSnifferRx",

                     "Trace source simulating a wifi device in monitor mode sniffing all received frames",

                     MakeTraceSourceAccessor (&WifiPhy::m_phyMonitorSniffRxTrace))

    .AddTraceSource ("MonitorSnifferTx",

                     "Trace source simulating the capability of a wifi device in monitor mode to sniff all frames being transmitted",

                     MakeTraceSourceAccessor (&WifiPhy::m_phyMonitorSniffTxTrace))

  ;

  return tid;

}

WifiPhy::WifiPhy ()

{

  NS_LOG_FUNCTION (this);

}

WifiPhy::~WifiPhy ()

{

  NS_LOG_FUNCTION (this);

}

//Added by Ghada to support 11n

//return the L-SIG

WifiMode

WifiPhy::GetMFPlcpHeaderMode (WifiMode payloadMode, WifiPreamble preamble)

{

    switch (payloadMode.GetBandwidth ())

       {

       case 20000000:

          return WifiPhy::GetOfdmRate6_5MbpsBW20MHz ();

        case 40000000:

           return WifiPhy::GetOfdmRate13_5MbpsBW40MHz ();

        default:

            return WifiPhy::GetOfdmRate6_5MbpsBW20MHz ();

      }

}

uint32_t

WifiPhy::GetPlcpHtTrainingSymbolDurationMicroSeconds (WifiMode payloadMode, WifiPreamble preamble, WifiTxVector txvector)

{

   switch (preamble)

     {

     case WIFI_PREAMBLE_HT_MF:

        return 4+ (4* txvector.GetNss());

     case WIFI_PREAMBLE_HT_GF:

         return (4*txvector.GetNss())+(4*txvector.GetNess());

      default:

         // no training for non HT

          return 0;

      }

}

//return L-SIG

uint32_t

WifiPhy::GetPlcpHtSigHeaderDurationMicroSeconds (WifiMode payloadMode, WifiPreamble preamble)

{

         switch (preamble)

            {

             case WIFI_PREAMBLE_HT_MF:

               // HT-SIG

               return 8;

             case WIFI_PREAMBLE_HT_GF:

               //HT-SIG

               return 8;

             default:

               // no HT-SIG for non HT

               return 0;

            }

}

//end added by Ghada

WifiMode

WifiPhy::GetPlcpHeaderMode (WifiMode payloadMode, WifiPreamble preamble)

{

  switch (payloadMode.GetModulationClass ())

    {

    case WIFI_MOD_CLASS_OFDM:

      {

        switch (payloadMode.GetBandwidth ())

          {

          case 5000000:

            return WifiPhy::GetOfdmRate1_5MbpsBW5MHz ();

          case 10000000:

            return WifiPhy::GetOfdmRate3MbpsBW10MHz ();

          default:

            // actually this is only the first part of the PlcpHeader,

            // because the last 16 bits of the PlcpHeader are using the

            // same mode of the payload

            return WifiPhy::GetOfdmRate6Mbps ();

          }

      }

    //Added by Ghada to support 11n

    case WIFI_MOD_CLASS_HT:

      {  //return the HT-SIG

         // IEEE Std 802.11n, 20.3.23

         switch (preamble)

           {

            case WIFI_PREAMBLE_HT_MF:

                switch (payloadMode.GetBandwidth ())

                  {

                   case 20000000:

                      return WifiPhy::GetOfdmRate13MbpsBW20MHz ();

                   case 40000000:

                      return WifiPhy::GetOfdmRate27MbpsBW40MHz ();

                   default:

                      return WifiPhy::GetOfdmRate13MbpsBW20MHz ();

                  }

            case WIFI_PREAMBLE_HT_GF:

                  switch (payloadMode.GetBandwidth ())

                  {

                   case 20000000:

                      return WifiPhy::GetOfdmRate13MbpsBW20MHz ();

                   case 40000000:

                      return WifiPhy::GetOfdmRate27MbpsBW40MHz ();

                   default:

                      return WifiPhy::GetOfdmRate13MbpsBW20MHz ();

                  }

             default:

                return WifiPhy::GetOfdmRate6Mbps ();

          }

      }

    case WIFI_MOD_CLASS_ERP_OFDM:

      return WifiPhy::GetErpOfdmRate6Mbps ();

    case WIFI_MOD_CLASS_DSSS:

      if (preamble == WIFI_PREAMBLE_LONG)

        {

          return WifiPhy::GetDsssRate1Mbps ();

        }

      else  //  WIFI_PREAMBLE_SHORT

        {

          return WifiPhy::GetDsssRate2Mbps ();

        }

    default:

      NS_FATAL_ERROR ("unsupported modulation class");

      return WifiMode ();

    }

}

uint32_t

WifiPhy::GetPlcpHeaderDurationMicroSeconds (WifiMode payloadMode, WifiPreamble preamble)

{

  switch (payloadMode.GetModulationClass ())

    {

    case WIFI_MOD_CLASS_OFDM:

      {

        switch (payloadMode.GetBandwidth ())

          {

          case 20000000:

          default:

            // We return the duration of the SIGNAL field only, since the

            // SERVICE field (which strictly speaking belongs to the PLCP

            // payload mode.

            return 4;

          case 10000000:

            return 8;

          case 5000000:

            return 16;

          }

      }

     //Added by Ghada to support 11n

    case WIFI_MOD_CLASS_HT:

      { //IEEE 802.11n Figure 20.1

         switch (preamble)

            {

             case WIFI_PREAMBLE_HT_MF:

               // L-SIG

               return 4;

             case WIFI_PREAMBLE_HT_GF:

               //L-SIG

               return 0;

             default:

               // L-SIG

               return 4;

            }

      }

    case WIFI_MOD_CLASS_ERP_OFDM:

      return 4;

    case WIFI_MOD_CLASS_DSSS:

      if (preamble == WIFI_PREAMBLE_SHORT)

        {

          return 24;

        }

      else // WIFI_PREAMBLE_LONG

        {

          return 48;

        }

    default:

      NS_FATAL_ERROR ("unsupported modulation class");

      return 0;

    }

}

uint32_t

WifiPhy::GetPlcpPreambleDurationMicroSeconds (WifiMode payloadMode, WifiPreamble preamble)

{

  switch (payloadMode.GetModulationClass ())

    {

    case WIFI_MOD_CLASS_OFDM:

      {

        switch (payloadMode.GetBandwidth ())

          {

          case 20000000:

          default:

            return 16;

          case 10000000:

            return 32;

          case 5000000:

            return 64;

          }

      }

    case WIFI_MOD_CLASS_HT:

      { //IEEE 802.11n Figure 20.1 the training symbols before L_SIG or HT_SIG

           return 16;

      }

    case WIFI_MOD_CLASS_ERP_OFDM:

      return 16;

    case WIFI_MOD_CLASS_DSSS:

      if (preamble == WIFI_PREAMBLE_SHORT)

        {

          return 72;

        }

      else // WIFI_PREAMBLE_LONG

        {

          return 144;

        }

    default:

      NS_FATAL_ERROR ("unsupported modulation class");

      return 0;

    }

}

double

WifiPhy::GetPayloadDurationMicroSeconds (uint32_t size, WifiTxVector txvector)

{

  WifiMode payloadMode=txvector.GetMode();

  NS_LOG_FUNCTION (size << payloadMode);

  switch (payloadMode.GetModulationClass ())

    {

    case WIFI_MOD_CLASS_OFDM:

    case WIFI_MOD_CLASS_ERP_OFDM:

      {

        uint32_t symbolDurationUs;

        switch (payloadMode.GetBandwidth ())

          {

          case 20000000:

          default:

            symbolDurationUs = 4;

            break;

          case 10000000:

            symbolDurationUs = 8;

            break;

          case 5000000:

            symbolDurationUs = 16;

            break;

          }

        // corresponds to N_{DBPS} in the table

        double numDataBitsPerSymbol = payloadMode.GetDataRate () * symbolDurationUs / 1e6;

        uint32_t numSymbols = lrint (ceil ((16 + size * 8.0 + 6.0) / numDataBitsPerSymbol));

        // Add signal extension for ERP PHY

        if (payloadMode.GetModulationClass () == WIFI_MOD_CLASS_ERP_OFDM)

          {

            return numSymbols * symbolDurationUs + 6;

          }

        else

          {

            return numSymbols * symbolDurationUs;

          }

      }

    case WIFI_MOD_CLASS_HT:

      {

         double symbolDurationUs;

         double m_Stbc;

        //if short GI data rate is used then symbol duration is 3.6us else symbol duration is 4us

        //In the future has to create a stationmanager that only uses these data rates if sender and reciever support GI

         if (payloadMode.GetUniqueName() == "OfdmRate135MbpsBW40MHzShGi" || payloadMode.GetUniqueName() == "OfdmRate65MbpsBW20MHzShGi" )

           {

             symbolDurationUs=3.6;

           }

         else

           {

             switch (payloadMode.GetDataRate ()/ (txvector.GetNss()))

               { //shortGi

                  case 7200000:

                  case 14400000:

                  case 21700000:

                  case 28900000:

                  case 43300000:

                  case 57800000:

                  case 72200000:

                  case 15000000:

                  case 30000000:

                  case 45000000:

                  case 60000000:

                  case 90000000:

                  case 120000000:

                  case 150000000:

                    symbolDurationUs=3.6;

                    break;               

                 default:

                    symbolDurationUs=4;

              }

           }

         if  (txvector.IsStbc())

            m_Stbc=2;

         else

           m_Stbc=1;

         double numDataBitsPerSymbol = payloadMode.GetDataRate () *txvector.GetNss()  * symbolDurationUs / 1e6;

         //check tables 20-35 and 20-36 in the standard to get cases when nes =2

         double Nes=1;

        // IEEE Std 802.11n, section 20.3.11, equation (20-32)

        uint32_t numSymbols = lrint (m_Stbc*ceil ((16 + size * 8.0 + 6.0*Nes) / (m_Stbc* numDataBitsPerSymbol)));

        return numSymbols * symbolDurationUs;

      }

    case WIFI_MOD_CLASS_DSSS:

      NS_LOG_LOGIC (" size=" << size

                             << " mode=" << payloadMode

                             << " rate=" << payloadMode.GetDataRate () );

      return lrint (ceil ((size * 8.0) / (payloadMode.GetDataRate () / 1.0e6)));

    default:

      NS_FATAL_ERROR ("unsupported modulation class");

      return 0;

    }

}

Time

WifiPhy::CalculateTxDuration (uint32_t size, WifiTxVector txvector, WifiPreamble preamble)

{

  WifiMode payloadMode=txvector.GetMode();

  double duration = GetPlcpPreambleDurationMicroSeconds (payloadMode, preamble)

    + GetPlcpHeaderDurationMicroSeconds (payloadMode, preamble)

    + GetPlcpHtSigHeaderDurationMicroSeconds (payloadMode, preamble)

    + GetPlcpHtTrainingSymbolDurationMicroSeconds (payloadMode, preamble,txvector)

    + GetPayloadDurationMicroSeconds (size, txvector);

  return MicroSeconds (duration);

}

void

WifiPhy::NotifyTxBegin (Ptr<const Packet> packet)

{

  m_phyTxBeginTrace (packet);

}

void

WifiPhy::NotifyTxEnd (Ptr<const Packet> packet)

{

  m_phyTxEndTrace (packet);

}

void

WifiPhy::NotifyTxDrop (Ptr<const Packet> packet)

{

  m_phyTxDropTrace (packet);

}

void

WifiPhy::NotifyRxBegin (Ptr<const Packet> packet)

{

  m_phyRxBeginTrace (packet);

}

void

WifiPhy::NotifyRxEnd (Ptr<const Packet> packet)

{

  m_phyRxEndTrace (packet);

}

void

WifiPhy::NotifyRxDrop (Ptr<const Packet> packet)

{

  m_phyRxDropTrace (packet);

}

void