he-ru.cc

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/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2018
 *
 * 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: Stefano Avallone <stavallo@unina.it>
 */

#include "he-ru.h"
#include "ns3/abort.h"

namespace ns3 {

const HeRu::SubcarrierGroups HeRu::m_heRuSubcarrierGroups =
{
  // RUs in a 20 MHz HE PPDU (Table 28-6)
  { {20, HeRu::RU_26_TONE}, { /* 1 */ {{-121, -96}},
      /* 2 */ {{-95, -70}},
      /* 3 */ {{-68, -43}},
      /* 4 */ {{-42, -17}},
      /* 5 */ {{-16, -4}, {4, 16}},
      /* 6 */ {{17, 42}},
      /* 7 */ {{43, 68}},
      /* 8 */ {{70, 95}},
      /* 9 */ {{96, 121}} } },
  { {20, HeRu::RU_52_TONE}, { /* 1 */ {{-121, -70}},
      /* 2 */ {{-68, -17}},
      /* 3 */ {{17, 68}},
      /* 4 */ {{70, 121}} } },
  { {20, HeRu::RU_106_TONE}, { /* 1 */ {{-122, -17}},
      /* 2 */ {{17, 122}} } },
  { {20, HeRu::RU_242_TONE}, { /* 1 */ {{-122, -2}, {2, 122}} } },
  // RUs in a 40 MHz HE PPDU (Table 28-7)
  { {40, HeRu::RU_26_TONE}, { /* 1 */ {{-243, -218}},
      /* 2 */ {{-217, -192}},
      /* 3 */ {{-189, -164}},
      /* 4 */ {{-163, -138}},
      /* 5 */ {{-136, -111}},
      /* 6 */ {{-109, -84}},
      /* 7 */ {{-83, -58}},
      /* 8 */ {{-55, -30}},
      /* 9 */ {{-29, -4}},
      /* 10 */ {{4, 29}},
      /* 11 */ {{30, 55}},
      /* 12 */ {{58, 83}},
      /* 13 */ {{84, 109}},
      /* 14 */ {{111, 136}},
      /* 15 */ {{138, 163}},
      /* 16 */ {{164, 189}},
      /* 17 */ {{192, 217}},
      /* 18 */ {{218, 243}} } },
  { {40, HeRu::RU_52_TONE}, { /* 1 */ {{-243, -192}},
      /* 2 */ {{-189, -138}},
      /* 3 */ {{-109, -58}},
      /* 4 */ {{-55, -4}},
      /* 5 */ {{4, 55}},
      /* 6 */ {{58, 109}},
      /* 7 */ {{138, 189}},
      /* 8 */ {{192, 243}} } },
  { {40, HeRu::RU_106_TONE}, { /* 1 */ {{-243, -138}},
      /* 2 */ {{-109, -4}},
      /* 3 */ {{4, 109}},
      /* 4 */ {{138, 243}} } },
  { {40, HeRu::RU_242_TONE}, { /* 1 */ {{-244, -3}},
      /* 2 */ {{3, 244}} } },
  { {40, HeRu::RU_484_TONE}, { /* 1 */ {{-244, -3}, {3, 244}} } },
  // RUs in an 80 MHz HE PPDU (Table 28-8)
  { {80, HeRu::RU_26_TONE}, { /* 1 */ {{-499, -474}},
      /* 2 */ {{-473, -448}},
      /* 3 */ {{-445, -420}},
      /* 4 */ {{-419, -394}},
      /* 5 */ {{-392, -367}},
      /* 6 */ {{-365, -340}},
      /* 7 */ {{-339, -314}},
      /* 8 */ {{-311, -286}},
      /* 9 */ {{-285, -260}},
      /* 10 */ {{-257, -232}},
      /* 11 */ {{-231, -206}},
      /* 12 */ {{-203, -178}},
      /* 13 */ {{-177, -152}},
      /* 14 */ {{-150, -125}},
      /* 15 */ {{-123, -98}},
      /* 16 */ {{-97, -72}},
      /* 17 */ {{-69, -44}},
      /* 18 */ {{-43, -18}},
      /* 19 */ {{-16, -4}, {4, 16}},
      /* 20 */ {{18, 43}},
      /* 21 */ {{44, 69}},
      /* 22 */ {{72, 97}},
      /* 23 */ {{98, 123}},
      /* 24 */ {{125, 150}},
      /* 25 */ {{152, 177}},
      /* 26 */ {{178, 203}},
      /* 27 */ {{206, 231}},
      /* 28 */ {{232, 257}},
      /* 29 */ {{260, 285}},
      /* 30 */ {{286, 311}},
      /* 31 */ {{314, 339}},
      /* 32 */ {{340, 365}},
      /* 33 */ {{367, 392}},
      /* 34 */ {{394, 419}},
      /* 35 */ {{420, 445}},
      /* 36 */ {{448, 473}},
      /* 37 */ {{474, 499}} } },
  { {80, HeRu::RU_52_TONE}, { /* 1 */ {{-499, -448}},
      /* 2 */ {{-445, -394}},
      /* 3 */ {{-365, -314}},
      /* 4 */ {{-311, -260}},
      /* 5 */ {{-257, -206}},
      /* 6 */ {{-203, -152}},
      /* 7 */ {{-123, -72}},
      /* 8 */ {{-69, -18}},
      /* 9 */ {{18, 69}},
      /* 10 */ {{72, 123}},
      /* 11 */ {{152, 203}},
      /* 12 */ {{206, 257}},
      /* 13 */ {{260, 311}},
      /* 14 */ {{314, 365}},
      /* 15 */ {{394, 445}},
      /* 16 */ {{448, 499}} } },
  { {80, HeRu::RU_106_TONE}, { /* 1 */ {{-499, -394}},
      /* 2 */ {{-365, -260}},
      /* 3 */ {{-257, -152}},
      /* 4 */ {{-123, -18}},
      /* 5 */ {{18, 123}},
      /* 6 */ {{152, 257}},
      /* 7 */ {{260, 365}},
      /* 8 */ {{394, 499}} } },
  { {80, HeRu::RU_242_TONE}, { /* 1 */ {{-500, -259}},
      /* 2 */ {{-258, -17}},
      /* 3 */ {{17, 258}},
      /* 4 */ {{259, 500}} } },
  { {80, HeRu::RU_484_TONE}, { /* 1 */ {{-500, -17}},
      /* 2 */ {{17, 500}} } },
  { {80, HeRu::RU_996_TONE}, { /* 1 */ {{-500, -3}, {3, 500}} } }
};


std::size_t
HeRu::GetNRus (uint8_t bw, RuType ruType)
{
  if (bw == 160 && ruType == RU_2x996_TONE)
    {
      return 1;
    }

  // if the bandwidth is 160MHz, search for the number of RUs available
  // in 80MHz and double the result.
  auto it = m_heRuSubcarrierGroups.find ({(bw == 160 ? 80 : bw), ruType});

  if (it == m_heRuSubcarrierGroups.end ())
    {
      return 0;
    }

  return (bw == 160 ? 2 : 1) * it->second.size ();
}

HeRu::SubcarrierGroup
HeRu::GetSubcarrierGroup (uint8_t bw, RuType ruType, std::size_t index)
{
  if (ruType == HeRu::RU_2x996_TONE) //handle special case of RU covering 160 MHz channel
    {
      NS_ABORT_MSG_IF (bw != 160, "2x996 tone RU can only be used on 160 MHz band");
      return {{-1012, -3}, {3, 1012}};
    }

  // Determine the shift to apply to tone indices for 160 MHz channel (i.e. -1012 to 1012), since
  // m_heRuSubcarrierGroups contains indices for primary 80 MHz subchannel (i.e. from -500 to 500).
  // The index is used to that aim.
  std::size_t indexInPrimary80MHz = index;
  std::size_t numRus = GetNRus (bw, ruType);
  int16_t shift = (bw == 160) ? -512 : 0;
  if (bw == 160 && index > (numRus / 2))
    {
      // The provided index is that of the secondary 80 MHz subchannel
      indexInPrimary80MHz = index - (numRus / 2);
      shift = 512;
    }

  auto it = m_heRuSubcarrierGroups.find ({(bw == 160 ? 80 : bw), ruType});

  NS_ABORT_MSG_IF (it == m_heRuSubcarrierGroups.end (), "RU not found");
  NS_ABORT_MSG_IF (!indexInPrimary80MHz || indexInPrimary80MHz > it->second.size (), "RU index not available");

  SubcarrierGroup group = it->second.at (indexInPrimary80MHz - 1);
  if (bw == 160)
    {
      for (auto & range : group)
        {
          range.first += shift;
          range.second += shift;
        }
    }
  return group;
}

#ifdef NOTYET
// Currently unused methods planned for ns-3.34; causing
// problems with API scanning (see issue #308)
bool
HeRu::DoesOverlap (uint8_t bw, RuSpec ru, const std::vector<RuSpec> &v)
{
  // A 2x996-tone RU spans 160 MHz, hence it overlaps with any other RU
  if (bw == 160 && ru.ruType == RU_2x996_TONE && !v.empty ())
    {
      return true;
    }

  SubcarrierGroup groups = GetSubcarrierGroup (bw, ru.ruType, ru.index);
  for (auto& p : v)
    {
      if (ru.primary80MHz != p.primary80MHz)
        {
          // the two RUs are located in distinct 80MHz bands
          continue;
        }
      if (DoesOverlap (bw, p, groups))
        {
          return true;
        }
    }
  return false;
}

bool
HeRu::DoesOverlap (uint8_t bw, RuSpec ru, const SubcarrierGroup &toneRanges)
{
  for (const auto & range : toneRanges)
    {
      if (bw == 160 && ru.ruType == RU_2x996_TONE)
        {
          return true;
        }

      SubcarrierGroup rangesRu = GetSubcarrierGroup (bw, ru.ruType, ru.index);
      for (auto& r : rangesRu)
        {
          if (range.second >= r.first && r.second >= range.first)
            {
              return true;
            }
        }
    }
  return false;
}
#endif

std::ostream& operator<< (std::ostream& os, const HeRu::RuType &ruType)
{
  switch (ruType)
    {
      case HeRu::RU_26_TONE:
        os << "26-tones";
        break;
      case HeRu::RU_52_TONE:
        os << "52-tones";
        break;
      case HeRu::RU_106_TONE:
        os << "106-tones";
        break;
      case HeRu::RU_242_TONE:
        os << "242-tones";
        break;
      case HeRu::RU_484_TONE:
        os << "484-tones";
        break;
      case HeRu::RU_996_TONE:
        os << "996-tones";
        break;
      case HeRu::RU_2x996_TONE:
        os << "2x996-tones";
        break;
      default:
        NS_FATAL_ERROR ("Unknown RU type");
    }
  return os;
}

std::ostream& operator<< (std::ostream& os, const HeRu::RuSpec &ru)
{
  os << "RU{" << ru.ruType << "/" << ru.index << "/" << (ru.primary80MHz ? "primary80MHz" : "secondary80MHz") << "}";
  return os;
}

uint16_t
HeRu::GetBandwidth (RuType ruType)
{
  switch (ruType)
    {
      case RU_26_TONE:
        return 2;
      case RU_52_TONE:
        return 4;
      case RU_106_TONE:
        return 8;
      case RU_242_TONE:
        return 20;
      case RU_484_TONE:
        return 40;
      case RU_996_TONE:
        return 80;
      case RU_2x996_TONE:
        return 160;
      default:
        NS_ABORT_MSG ("RU type " << ruType << " not found");
        return 0;
    }
}

HeRu::RuType
HeRu::GetEqualSizedRusForStations (uint16_t bandwidth, std::size_t& nStations)
{
  RuType ruType;
  uint8_t nRusAssigned = 0;

  // iterate over all the available RU types
  for (auto& ru : m_heRuSubcarrierGroups)
    {
      if (ru.first.first == bandwidth && ru.second.size () <= nStations)
        {
          ruType = ru.first.second;
          nRusAssigned = ru.second.size ();
          break;
        }
      else if (bandwidth == 160 && ru.first.first == 80 && (2 * ru.second.size () <= nStations))
        {
          ruType = ru.first.second;
          nRusAssigned = 2 * ru.second.size ();
          break;
        }
    }
  if (nRusAssigned == 0)
    {
      NS_ABORT_IF (bandwidth != 160 || nStations != 1);
      nRusAssigned = 1;
      ruType = RU_2x996_TONE;
    }

  nStations = nRusAssigned;
  return ruType;
}

} //namespace ns3