/*

 * 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/random-variable.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 <math.h>

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);

}

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:

            // IEEE Std 802.11-2007, 17.3.2

            // 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 ();

          }

      }

    case WIFI_MOD_CLASS_ERP_OFDM:

      return WifiPhy::GetErpOfdmRate6Mbps ();

    case WIFI_MOD_CLASS_DSSS:

      if (preamble == WIFI_PREAMBLE_LONG)

        {

          // IEEE Std 802.11-2007, sections 15.2.3 and 18.2.2.1

          return WifiPhy::GetDsssRate1Mbps ();

        }

      else  //  WIFI_PREAMBLE_SHORT

        {

          // IEEE Std 802.11-2007, section 18.2.2.2

          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:

            // IEEE Std 802.11-2007, section 17.3.3 and figure 17-4

            // also section 17.3.2.3, table 17-4

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

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

            // header, see section 17.3.2 and figure 17-1) is sent using the

            // payload mode.

            return 4;

          case 10000000:

            // IEEE Std 802.11-2007, section 17.3.2.3, table 17-4

            return 8;

          case 5000000:

            // IEEE Std 802.11-2007, section 17.3.2.3, table 17-4

            return 16;

          }

      }

    case WIFI_MOD_CLASS_ERP_OFDM:

      return 16;

    case WIFI_MOD_CLASS_DSSS:

      if (preamble == WIFI_PREAMBLE_SHORT)

        {

          // IEEE Std 802.11-2007, section 18.2.2.2 and figure 18-2

          return 24;

        }

      else // WIFI_PREAMBLE_LONG

        {

          // IEEE Std 802.11-2007, sections 18.2.2.1 and figure 18-1

          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:

            // IEEE Std 802.11-2007, section 17.3.3,  figure 17-4

            // also section 17.3.2.3, table 17-4

            return 16;

          case 10000000:

            // IEEE Std 802.11-2007, section 17.3.3, table 17-4

            // also section 17.3.2.3, table 17-4

            return 32;

          case 5000000:

            // IEEE Std 802.11-2007, section 17.3.3

            // also section 17.3.2.3, table 17-4

            return 64;

          }

      }

    case WIFI_MOD_CLASS_ERP_OFDM:

      return 4;

    case WIFI_MOD_CLASS_DSSS:

      if (preamble == WIFI_PREAMBLE_SHORT)

        {

          // IEEE Std 802.11-2007, section 18.2.2.2 and figure 18-2

          return 72;

        }

      else // WIFI_PREAMBLE_LONG

        {

          // IEEE Std 802.11-2007, sections 18.2.2.1 and figure 18-1

          return 144;

        }

    default:

      NS_FATAL_ERROR ("unsupported modulation class");

      return 0;

    }

}

uint32_t

WifiPhy::GetPayloadDurationMicroSeconds (uint32_t size, WifiMode payloadMode)

{

  NS_LOG_FUNCTION (size << payloadMode);

  switch (payloadMode.GetModulationClass ())

    {

    case WIFI_MOD_CLASS_OFDM:

    case WIFI_MOD_CLASS_ERP_OFDM:

      {

        // IEEE Std 802.11-2007, section 17.3.2.3, table 17-4

        // corresponds to T_{SYM} in the table

        uint32_t symbolDurationUs;

        switch (payloadMode.GetBandwidth ())

          {

          case 20000000:

          default:

            symbolDurationUs = 4;

            break;

          case 10000000:

            symbolDurationUs = 8;

            break;

          case 5000000:

            symbolDurationUs = 16;

            break;

          }

        // IEEE Std 802.11-2007, section 17.3.2.2, table 17-3

        // corresponds to N_{DBPS} in the table

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

        // IEEE Std 802.11-2007, section 17.3.5.3, equation (17-11)

        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_DSSS:

      // IEEE Std 802.11-2007, section 18.2.3.5

      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, WifiMode payloadMode, WifiPreamble preamble)

{

  uint32_t duration = GetPlcpPreambleDurationMicroSeconds (payloadMode, preamble)

    + GetPlcpHeaderDurationMicroSeconds (payloadMode, preamble)

    + GetPayloadDurationMicroSeconds (size, payloadMode);

  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

WifiPhy::NotifyMonitorSniffRx (Ptr<const Packet> packet, uint16_t channelFreqMhz, uint16_t channelNumber, uint32_t rate, bool isShortPreamble, double signalDbm, double noiseDbm)

{

  m_phyMonitorSniffRxTrace (packet, channelFreqMhz, channelNumber, rate, isShortPreamble, signalDbm, noiseDbm);

}

void

WifiPhy::NotifyMonitorSniffTx (Ptr<const Packet> packet, uint16_t channelFreqMhz, uint16_t channelNumber, uint32_t rate, bool isShortPreamble)

{

  m_phyMonitorSniffTxTrace (packet, channelFreqMhz, channelNumber, rate, isShortPreamble);

}

/**

 * Clause 15 rates (DSSS)

 */

WifiMode

WifiPhy::GetDsssRate1Mbps ()

{

  static WifiMode mode =

    WifiModeFactory::CreateWifiMode ("DsssRate1Mbps",

                                     WIFI_MOD_CLASS_DSSS,

                                     true,

                                     22000000, 1000000,

                                     WIFI_CODE_RATE_UNDEFINED,

                                     2);

  return mode;

}

WifiMode

WifiPhy::GetDsssRate2Mbps ()

{

  static WifiMode mode =

    WifiModeFactory::CreateWifiMode ("DsssRate2Mbps",

                                     WIFI_MOD_CLASS_DSSS,

                                     true,

                                     22000000, 2000000,

                                     WIFI_CODE_RATE_UNDEFINED,

                                     4);

  return mode;

}

/**

 * Clause 18 rates (HR/DSSS)

 */

WifiMode

WifiPhy::GetDsssRate5_5Mbps ()

{

  static WifiMode mode =

    WifiModeFactory::CreateWifiMode ("DsssRate5_5Mbps",

                                     WIFI_MOD_CLASS_DSSS,

                                     true,

                                     22000000, 5500000,

                                     WIFI_CODE_RATE_UNDEFINED,

                                     4);

  return mode;

}

WifiMode

WifiPhy::GetDsssRate11Mbps ()

{

  static WifiMode mode =

    WifiModeFactory::CreateWifiMode ("DsssRate11Mbps",

                                     WIFI_MOD_CLASS_DSSS,

                                     true,

                                     22000000, 11000000,

                                     WIFI_CODE_RATE_UNDEFINED,

                                     4);

  return mode;

}

/**

 * Clause 19.5 rates (ERP-OFDM)

 */

WifiMode

WifiPhy::GetErpOfdmRate6Mbps ()

{

  static WifiMode mode =

    WifiModeFactory::CreateWifiMode ("ErpOfdmRate6Mbps",

                                     WIFI_MOD_CLASS_ERP_OFDM,

                                     true,

                                     20000000, 6000000,

                                     WIFI_CODE_RATE_1_2,

                                     2);

  return mode;

}

WifiMode

WifiPhy::GetErpOfdmRate9Mbps ()

{

  static WifiMode mode =

    WifiModeFactory::CreateWifiMode ("ErpOfdmRate9Mbps",

                                     WIFI_MOD_CLASS_ERP_OFDM,

                                     false,

                                     20000000, 9000000,

                                     WIFI_CODE_RATE_3_4,

                                     2);

  return mode;

}

WifiMode

WifiPhy::GetErpOfdmRate12Mbps ()

{

  static WifiMode mode =

    WifiModeFactory::CreateWifiMode ("ErpOfdmRate12Mbps",

                                     WIFI_MOD_CLASS_ERP_OFDM,

                                     true,

                                     20000000, 12000000,

                                     WIFI_CODE_RATE_1_2,

                                     4);

  return mode;

}

WifiMode

WifiPhy::GetErpOfdmRate18Mbps ()

{

  static WifiMode mode =

    WifiModeFactory::CreateWifiMode ("ErpOfdmRate18Mbps",

                                     WIFI_MOD_CLASS_ERP_OFDM,

                                     false,

                                     20000000, 18000000,

                                     WIFI_CODE_RATE_3_4,

                                     4);

  return mode;

}

WifiMode

WifiPhy::GetErpOfdmRate24Mbps ()

{

  static WifiMode mode =

    WifiModeFactory::CreateWifiMode ("ErpOfdmRate24Mbps",

                                     WIFI_MOD_CLASS_ERP_OFDM,

                                     true,

                                     20000000, 24000000,

                                     WIFI_CODE_RATE_1_2,

                                     16);

  return mode;

}

WifiMode

WifiPhy::GetErpOfdmRate36Mbps ()

{

  static WifiMode mode =

    WifiModeFactory::CreateWifiMode ("ErpOfdmRate36Mbps",

                                     WIFI_MOD_CLASS_ERP_OFDM,

                                     false,

                                     20000000, 36000000,

                                     WIFI_CODE_RATE_3_4,

                                     16);

  return mode;