From 16a4d770ef9cbee821ec8ec95554116a862e84ec Mon Sep 17 00:00:00 2001
From: Alexander Krotov <krotov@iitp.ru>
Date: Sun, 7 Aug 2016 20:38:18 +0300
Subject: [PATCH] spectrum: (fixes #2467) Do not schedule StartRx for receivers
 with orthogonal SpectrumModels

This change greatly reduces number of StartRx calls, propagation delay
computations and SpectrumValue conversions for scenarios with large number
of transmitters and receivers operating in different non-overlapping channels,
i.e., Wi-Fi scenarios with multiple BSS operating in different channels.
---
 .../model/multi-model-spectrum-channel.cc     | 25 +++++++++++++------
 src/spectrum/model/spectrum-model.cc          | 19 ++++++++++++++
 src/spectrum/model/spectrum-model.h           |  8 ++++++
 3 files changed, 44 insertions(+), 8 deletions(-)

diff --git a/src/spectrum/model/multi-model-spectrum-channel.cc b/src/spectrum/model/multi-model-spectrum-channel.cc
index be45abb89..edd5fa10f 100644
--- a/src/spectrum/model/multi-model-spectrum-channel.cc
+++ b/src/spectrum/model/multi-model-spectrum-channel.cc
@@ -190,11 +190,16 @@ MultiModelSpectrumChannel::AddRx (Ptr<SpectrumPhy> phy)
            ++txInfoIterator)
         {
           Ptr<const SpectrumModel> txSpectrumModel = txInfoIterator->second.m_txSpectrumModel;
-          NS_LOG_LOGIC ("Creating converters between SpectrumModelUids " << txSpectrumModel->GetUid () << " and " << rxSpectrumModelUid );
-          SpectrumConverter converter (txSpectrumModel, rxSpectrumModel);
-          std::pair<SpectrumConverterMap_t::iterator, bool> ret2;
-          ret2 = txInfoIterator->second.m_spectrumConverterMap.insert (std::make_pair (rxSpectrumModelUid, converter));
-          NS_ASSERT (ret2.second);
+          SpectrumModelUid_t txSpectrumModelUid = txSpectrumModel->GetUid ();
+
+          if (rxSpectrumModelUid != txSpectrumModelUid && !txSpectrumModel->IsOrthogonal (*rxSpectrumModel))
+            {
+              NS_LOG_LOGIC ("Creating converter between SpectrumModelUid " << txSpectrumModel->GetUid () << " and " << rxSpectrumModelUid);
+              SpectrumConverter converter (txSpectrumModel, rxSpectrumModel);
+              std::pair<SpectrumConverterMap_t::iterator, bool> ret2;
+              ret2 = txInfoIterator->second.m_spectrumConverterMap.insert (std::make_pair (rxSpectrumModelUid, converter));
+              NS_ASSERT (ret2.second);
+            }
         }
     }
   else
@@ -231,9 +236,9 @@ MultiModelSpectrumChannel::FindAndEventuallyAddTxSpectrumModel (Ptr<const Spectr
           Ptr<const SpectrumModel> rxSpectrumModel = rxInfoIterator->second.m_rxSpectrumModel;
           SpectrumModelUid_t rxSpectrumModelUid = rxSpectrumModel->GetUid ();
 
-          if (rxSpectrumModelUid != txSpectrumModelUid)
+          if (rxSpectrumModelUid != txSpectrumModelUid && !txSpectrumModel->IsOrthogonal (*rxSpectrumModel))
             {
-              NS_LOG_LOGIC ("Creating converters between SpectrumModelUids " << txSpectrumModelUid << " and " << rxSpectrumModelUid );
+              NS_LOG_LOGIC ("Creating converter between SpectrumModelUid " << txSpectrumModelUid << " and " << rxSpectrumModelUid);
 
               SpectrumConverter converter (txSpectrumModel, rxSpectrumModel);
               std::pair<SpectrumConverterMap_t::iterator, bool> ret2;
@@ -289,7 +294,11 @@ MultiModelSpectrumChannel::StartTx (Ptr<SpectrumSignalParameters> txParams)
         {
           NS_LOG_LOGIC (" converting txPowerSpectrum SpectrumModelUids" << txSpectrumModelUid << " --> " << rxSpectrumModelUid);
           SpectrumConverterMap_t::const_iterator rxConverterIterator = txInfoIteratorerator->second.m_spectrumConverterMap.find (rxSpectrumModelUid);
-          NS_ASSERT (rxConverterIterator != txInfoIteratorerator->second.m_spectrumConverterMap.end ());
+          if (rxConverterIterator == txInfoIteratorerator->second.m_spectrumConverterMap.end ())
+            {
+              // No converter means TX SpectrumModel is orthogonal to RX SpectrumModel
+              continue;
+            }
           convertedTxPowerSpectrum = rxConverterIterator->second.Convert (txParams->psd);
         }
 
diff --git a/src/spectrum/model/spectrum-model.cc b/src/spectrum/model/spectrum-model.cc
index 29ab93c5b..e89e223da 100644
--- a/src/spectrum/model/spectrum-model.cc
+++ b/src/spectrum/model/spectrum-model.cc
@@ -101,6 +101,25 @@ SpectrumModel::GetUid () const
   return m_uid;
 }
 
+bool
+SpectrumModel::IsOrthogonal (const SpectrumModel &other) const
+{
+  for (Bands::const_iterator myIt = Begin ();
+       myIt != End ();
+       ++myIt)
+    {
+      for (Bands::const_iterator otherIt = other.Begin ();
+           otherIt != other.End ();
+           ++otherIt)
+        {
+          if (std::max (myIt->fl, otherIt->fl) < std::min (myIt->fh, otherIt->fh))
+            {
+              return false;
+            }
+        }
+    }
+  return true;
+}
 
 
 } // namespace ns3
diff --git a/src/spectrum/model/spectrum-model.h b/src/spectrum/model/spectrum-model.h
index 9ea4280f0..cb84a42f3 100644
--- a/src/spectrum/model/spectrum-model.h
+++ b/src/spectrum/model/spectrum-model.h
@@ -120,6 +120,14 @@ public:
    */
   Bands::const_iterator End () const;
 
+  /**
+   * Check if another SpectrumModels has bands orthogonal to our bands.
+   *
+   * \param other another SpectrumModel
+   * \returns true if bands are orthogonal
+   */
+  bool IsOrthogonal (const SpectrumModel &other) const;
+
 private:
   Bands m_bands;         //!< Actual definition of frequency bands within this SpectrumModel
   SpectrumModelUid_t m_uid;        //!< unique id for a given set of frequencies