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

/*

 * Copyright (c) 2010 TELEMATICS LAB, DEE - Politecnico di Bari

 *

 * 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: Giuseppe Piro  <g.piro@poliba.it>

 *         Nicola Baldo <nbaldo@cttc.es>

 */

#include <map>

#include <cmath>

#include <ns3/log.h>

#include <ns3/fatal-error.h>

#include "lte-spectrum-value-helper.h"

NS_LOG_COMPONENT_DEFINE ("LteSpectrumValueHelper");

namespace ns3 {

/**

 * Table 5.7.3-1 "E-UTRA channel numbers" from 3GPP TS 36.101

 * The table was converted to C syntax doing a cut & paste from TS 36.101 and running the following filter:

 * awk '{if ((NR % 7) == 1) printf("{"); printf ("%s",$0); if ((NR % 7) == 0) printf("},\n"); else printf(", ");}' | sed 's/ – /, /g' 

 */

struct EutraChannelNumbers

{

  uint8_t band;

  double fDlLow;

  uint16_t nOffsDl; 

  uint16_t rangeNdl1;

  uint16_t rangeNdl2;

  double fUlLow;

  uint16_t nOffsUl; 

  uint16_t rangeNul1;

  uint16_t rangeNul2;

} g_eutraChannelNumbers[] = {

  { 1, 2110, 0, 0, 599, 1920, 18000, 18000, 18599},

  { 2, 1930, 600, 600, 1199, 1850, 18600, 18600, 19199},

  { 3, 1805, 1200, 1200, 1949, 1710, 19200, 19200, 19949},

  { 4, 2110, 1950, 1950, 2399, 1710, 19950, 19950, 20399},

  { 5, 869, 2400, 2400, 2649, 824, 20400, 20400, 20649},

  { 6, 875, 2650, 2650, 2749, 830, 20650, 20650, 20749},

  { 7, 2620, 2750, 2750, 3449, 2500, 20750, 20750, 21449},

  { 8, 925, 3450, 3450, 3799, 880, 21450, 21450, 21799},

  { 9, 1844.9, 3800, 3800, 4149, 1749.9, 21800, 21800, 22149},

  { 10, 2110, 4150, 4150, 4749, 1710, 22150, 22150, 22749},

  { 11, 1475.9, 4750, 4750, 4949, 1427.9, 22750, 22750, 22949},

  { 12, 728, 5000, 5000, 5179, 698, 23000, 23000, 23179},

  { 13, 746, 5180, 5180, 5279, 777, 23180, 23180, 23279},

  { 14, 758, 5280, 5280, 5379, 788, 23280, 23280, 23379},

  { 17, 734, 5730, 5730, 5849, 704, 23730, 23730, 23849},

  { 18, 860, 5850, 5850, 5999, 815, 23850, 23850, 23999},

  { 19, 875, 6000, 6000, 6149, 830, 24000, 24000, 24149},

  { 20, 791, 6150, 6150, 6449, 832, 24150, 24150, 24449},

  { 21, 1495.9, 6450, 6450, 6599, 1447.9, 24450, 24450, 24599},

  { 33, 1900, 36000, 36000, 36199, 1900, 36000, 36000, 36199},

  { 34, 2010, 36200, 36200, 36349, 2010, 36200, 36200, 36349},

  { 35, 1850, 36350, 36350, 36949, 1850, 36350, 36350, 36949},

  { 36, 1930, 36950, 36950, 37549, 1930, 36950, 36950, 37549},

  { 37, 1910, 37550, 37550, 37749, 1910, 37550, 37550, 37749},

  { 38, 2570, 37750, 37750, 38249, 2570, 37750, 37750, 38249},

  { 39, 1880, 38250, 38250, 38649, 1880, 38250, 38250, 38649},

  { 40, 2300, 38650, 38650, 39649, 2300, 38650, 38650, 39649}

};

#define NUM_EUTRA_BANDS (sizeof (g_eutraChannelNumbers) / sizeof (EutraChannelNumbers))

double 

LteSpectrumValueHelper::GetCarrierFrequency (uint16_t earfcn)

{

  NS_LOG_FUNCTION (earfcn);

  if (earfcn < 7000)

    {

      // FDD downlink

      return GetDownlinkCarrierFrequency (earfcn);

    }

  else 

    {

      // either FDD uplink or TDD (for which uplink & downlink have same frequency)

      return GetUplinkCarrierFrequency (earfcn);

    }

}

double 

LteSpectrumValueHelper::GetDownlinkCarrierFrequency (uint16_t nDl)

{

  NS_LOG_FUNCTION (nDl);

  for (uint16_t i = 0; i < NUM_EUTRA_BANDS; ++i)

    {

      if ((g_eutraChannelNumbers[i].rangeNdl1 <= nDl)

          && (g_eutraChannelNumbers[i].rangeNdl2 >= nDl))

        {

          NS_LOG_LOGIC ("entry " << i << " fDlLow=" << g_eutraChannelNumbers[i].fDlLow);

          return 1.0e6 * (g_eutraChannelNumbers[i].fDlLow + 0.1 * (nDl - g_eutraChannelNumbers[i].nOffsDl));

        }

    }

  NS_LOG_ERROR ("invalid EARFCN " << nDl);

  return 0.0;

}

double 

LteSpectrumValueHelper::GetUplinkCarrierFrequency (uint16_t nUl)

{

  NS_LOG_FUNCTION (nUl);

  for (uint16_t i = 0; i < NUM_EUTRA_BANDS; ++i)

    {

      if ((g_eutraChannelNumbers[i].rangeNul1 <= nUl)

          && (g_eutraChannelNumbers[i].rangeNul2 >= nUl))

        {

          NS_LOG_LOGIC ("entry " << i << " fUlLow=" << g_eutraChannelNumbers[i].fUlLow);

          return 1.0e6 * (g_eutraChannelNumbers[i].fUlLow + 0.1 * (nUl - g_eutraChannelNumbers[i].nOffsUl));

        }

    }

  NS_LOG_ERROR ("invalid EARFCN " << nUl);

  return 0.0;

}

double 

LteSpectrumValueHelper::GetChannelBandwidth (uint8_t transmissionBandwidth)

{

  NS_LOG_FUNCTION ((uint16_t) transmissionBandwidth);

  switch (transmissionBandwidth)

    { 

    case 6:

      return 1.4e6;

    case 15:

      return 3.0e6;

    case 25:

      return 5.0e6;

    case 50:

      return 10.0e6;

    case 75:

      return 15.0e6;

    case 100:

      return 20.0e6;

    default:

      NS_FATAL_ERROR ("invalid bandwidth value " << (uint16_t) transmissionBandwidth);

    }

}

struct LteSpectrumModelId

{

  LteSpectrumModelId (uint16_t f, uint8_t b);

  uint16_t earfcn;

  uint8_t  bandwidth;

};

LteSpectrumModelId::LteSpectrumModelId (uint16_t f, uint8_t b)

  : earfcn (f), 

    bandwidth (b)

{

}

bool

operator < (const LteSpectrumModelId& a, const LteSpectrumModelId& b)

{

  return ( (a.earfcn < b.earfcn) || ( (a.earfcn == b.earfcn) && (a.bandwidth < b.bandwidth) ) );

}

static std::map<LteSpectrumModelId, Ptr<SpectrumModel> > g_lteSpectrumModelMap;

Ptr<SpectrumModel>

LteSpectrumValueHelper::GetSpectrumModel (uint16_t earfcn, uint8_t txBandwidthConfiguration)

{

  NS_LOG_FUNCTION (earfcn << (uint16_t) txBandwidthConfiguration);

  Ptr<SpectrumModel> ret;

  LteSpectrumModelId key (earfcn, txBandwidthConfiguration);

  std::map<LteSpectrumModelId, Ptr<SpectrumModel> >::iterator it = g_lteSpectrumModelMap.find (key);

  if (it != g_lteSpectrumModelMap.end ())

    {

      ret = it->second;

    }

  else

    {

      double fc = GetCarrierFrequency (earfcn);

      NS_ASSERT_MSG (fc != 0, "invalid EARFCN=" << earfcn);

      double f = fc - (txBandwidthConfiguration * 180e3 / 2.0);

      Bands rbs;

      for (uint8_t numrb = 0; numrb < txBandwidthConfiguration; ++numrb)

        {

          BandInfo rb; 

          rb.fl = f;

          f += 90e3;

          rb.fc = f;

          f += 90e3;

          rb.fh = f;

          rbs.push_back (rb);

        }

      ret = Create<SpectrumModel> (rbs);

      g_lteSpectrumModelMap.insert (std::pair<LteSpectrumModelId, Ptr<SpectrumModel> > (key, ret));

    }

  NS_LOG_LOGIC ("returning SpectrumModel::GetUid () == " << ret->GetUid ());

  return ret;

}

// just needed to log a std::vector<int> properly...

std::ostream&

operator << (std::ostream& os, const std::vector<int>& v)

{

  std::vector<int>::const_iterator it = v.begin ();

  while (it != v.end ())

    {

      os << *it << " " ;

      ++it;

    }

  os << std::endl;

  return os;

}

Ptr<SpectrumValue> 

LteSpectrumValueHelper::CreateTxPowerSpectralDensity (uint16_t earfcn, uint8_t txBandwidthConfiguration, double powerTx, std::vector <int> activeRbs)

{

  NS_LOG_FUNCTION (earfcn << (uint16_t) txBandwidthConfiguration << powerTx << activeRbs);

  Ptr<SpectrumModel> model = GetSpectrumModel (earfcn, txBandwidthConfiguration);

  Ptr<SpectrumValue> txPsd = Create <SpectrumValue> (model);

  // powerTx is expressed in dBm. We must convert it into natural unit.

  double powerTxW = pow (10., (powerTx - 30) / 10);

  double txPowerDensity = (powerTxW / (txBandwidthConfiguration * 180000));

  for (std::vector <int>::iterator it = activeRbs.begin (); it != activeRbs.end (); it++)

    {

      int rbId = (*it);

      (*txPsd)[rbId] = txPowerDensity;

    }

  NS_LOG_LOGIC (*txPsd);

  return txPsd;

}

Ptr<SpectrumValue>

LteSpectrumValueHelper::CreateNoisePowerSpectralDensity (uint16_t earfcn, uint8_t txBandwidthConfiguration, double noiseFigure)

{

  NS_LOG_FUNCTION (earfcn << (uint16_t) txBandwidthConfiguration << noiseFigure);

  Ptr<SpectrumModel> model = GetSpectrumModel (earfcn, txBandwidthConfiguration);

  return CreateNoisePowerSpectralDensity (noiseFigure, model);

}

Ptr<SpectrumValue>

LteSpectrumValueHelper::CreateNoisePowerSpectralDensity (double noiseFigureDb, Ptr<SpectrumModel> spectrumModel)

{

  NS_LOG_FUNCTION (noiseFigureDb << spectrumModel);

  // see "LTE - From theory to practice"

  // Section 22.4.4.2 Thermal Noise and Receiver Noise Figure

  const double kT_dBm_Hz = -174.0;  // dBm/Hz

  double kT_W_Hz = pow (10.0, (kT_dBm_Hz - 30) / 10.0);

  double noiseFigureLinear = pow (10.0, noiseFigureDb / 10.0);

  double noisePowerSpectralDensity =  kT_W_Hz * noiseFigureLinear;

  Ptr<SpectrumValue> noisePsd = Create <SpectrumValue> (spectrumModel);

  (*noisePsd) = noisePowerSpectralDensity;

  return noisePsd;

}

} // namespace ns3