wifi: Add useful methods to class HeRu

src/wifi/model/he/he-ru.cc

@@ -20,6 +20,7 @@
 
 #include "he-ru.h"
 #include "ns3/abort.h"
+#include "ns3/assert.h"
 
 namespace ns3 {
 
@@ -168,6 +169,80 @@ HeRu::GetNRus (uint16_t bw, RuType ruType)
   return (bw == 160 ? 2 : 1) * it->second.size ();
 }
 
+std::vector<HeRu::RuSpec>
+HeRu::GetRusOfType (uint16_t bw, HeRu::RuType ruType)
+{
+  if (ruType == HeRu::RU_2x996_TONE)
+    {
+      NS_ASSERT (bw >= 160);
+      return {{true, ruType, 1}};
+    }
+
+  std::vector<HeRu::RuSpec> ret;
+  std::vector<bool> primary80MHzSet {true};
+
+  if (bw == 160)
+    {
+      primary80MHzSet.push_back (false);
+      bw = 80;
+    }
+
+  for (auto primary80MHz : primary80MHzSet)
+    {
+      for (std::size_t ruIndex = 1; ruIndex <= HeRu::m_heRuSubcarrierGroups.at ({bw, ruType}).size (); ruIndex++)
+        {
+          ret.push_back ({primary80MHz, ruType, ruIndex});
+        }
+    }
+  return ret;
+}
+
+std::vector<HeRu::RuSpec>
+HeRu::GetCentral26TonesRus (uint16_t bw, HeRu::RuType ruType)
+{
+  std::vector<std::size_t> indices;
+
+  if (ruType == HeRu::RU_52_TONE || ruType == HeRu::RU_106_TONE)
+    {
+      if (bw == 20)
+        {
+          indices.push_back (5);
+        }
+      else if (bw == 40)
+        {
+          indices.insert (indices.end (), {5, 14});
+        }
+      else if (bw >= 80)
+        {
+          indices.insert (indices.end (), {5, 14, 19, 24, 33});
+        }
+    }
+  else if (ruType == HeRu::RU_242_TONE || ruType == HeRu::RU_484_TONE)
+    {
+      if (bw >= 80)
+        {
+          indices.push_back (19);
+        }
+    }
+
+  std::vector<HeRu::RuSpec> ret;
+  std::vector<bool> primary80MHzSet {true};
+
+  if (bw == 160)
+    {
+      primary80MHzSet.push_back (false);
+    }
+
+  for (auto primary80MHz : primary80MHzSet)
+    {
+      for (const auto& index : indices)
+        {
+          ret.push_back ({primary80MHz, HeRu::RU_26_TONE, index});
+        }
+    }
+  return ret;
+}
+
 HeRu::SubcarrierGroup
 HeRu::GetSubcarrierGroup (uint16_t bw, RuType ruType, std::size_t index)
 {
@@ -379,4 +454,70 @@ HeRu::GetRuType (uint16_t bandwidth)
     }
 }
 
+HeRu::RuType
+HeRu::GetEqualSizedRusForStations (uint16_t bandwidth, std::size_t& nStations,
+                                   std::size_t& nCentral26TonesRus)
+{
+  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;
+
+  switch (ruType)
+    {
+      case RU_52_TONE:
+      case RU_106_TONE:
+        if (bandwidth == 20)
+          {
+            nCentral26TonesRus = 1;
+          }
+        else if (bandwidth == 40)
+          {
+            nCentral26TonesRus = 2;
+          }
+        else
+          {
+            nCentral26TonesRus = 5;
+          }
+        break;
+      case RU_242_TONE:
+      case RU_484_TONE:
+        nCentral26TonesRus = (bandwidth >= 80 ? 1 : 0);
+        break;
+      default:
+        nCentral26TonesRus = 0;
+    }
+
+  if (bandwidth == 160)
+    {
+      nCentral26TonesRus *= 2;
+    }
+
+  return ruType;
+}
+
+
 } //namespace ns3

src/wifi/model/he/he-ru.h

@@ -79,6 +79,26 @@ public:
    */
   static std::size_t GetNRus (uint16_t bw, RuType ruType);
 
+  /**
+   * Get the set of distinct RUs of the given type (number of tones)
+   * available in a HE PPDU of the given bandwidth.
+   *
+   * \param bw the bandwidth (MHz) of the HE PPDU (20, 40, 80, 160)
+   * \param ruType the RU type (number of tones)
+   * \return the set of distinct RUs available
+   */
+  static std::vector<HeRu::RuSpec> GetRusOfType (uint16_t bw, HeRu::RuType ruType);
+
+  /**
+   * Get the set of 26-tone RUs that can be additionally allocated if the given
+   * bandwidth is split in RUs of the given type.
+   *
+   * \param bw the bandwidth (MHz) of the HE PPDU (20, 40, 80, 160)
+   * \param ruType the RU type (number of tones)
+   * \return the set of 26-tone RUs that can be additionally allocated
+   */
+  static std::vector<HeRu::RuSpec> GetCentral26TonesRus (uint16_t bw, HeRu::RuType ruType);
+
   /**
    * Get the subcarrier group of the RU having the given index among all the
    * RUs of the given type (number of tones) available in a HE PPDU of the
@@ -147,6 +167,22 @@ public:
    */
   static RuType GetRuType (uint16_t bandwidth);
 
+  /**
+   * Given the channel bandwidth and the number of stations candidate for being
+   * assigned an RU, maximize the number of candidate stations that can be assigned
+   * an RU subject to the constraint that all the stations must be assigned an RU
+   * of the same size (in terms of number of tones).
+   *
+   * \param bandwidth the channel bandwidth in MHz
+   * \param nStations the number of candidate stations. On return, it is set to
+   *                  the number of stations that are assigned an RU
+   * \param[out] nCentral26TonesRus the number of additional 26-tone RUs that can be
+   *                                allocated if the returned RU size is greater than 26 tones
+   * \return the RU type
+   */
+  static RuType GetEqualSizedRusForStations (uint16_t bandwidth, std::size_t& nStations,
+                                             std::size_t& nCentral26TonesRus);
+
   /// (bandwidth, number of tones) pair
   typedef std::pair<uint8_t, RuType> BwTonesPair;