wifi: Fix use of YansErrorRateModel for PHY headers

src/wifi/model/wifi-mode.cc

@@ -32,6 +32,11 @@ bool operator == (const WifiMode &a, const WifiMode &b)
   return a.GetUid () == b.GetUid ();
 }
 
+bool operator != (const WifiMode &a, const WifiMode &b)
+{
+  return a.GetUid () != b.GetUid ();
+}
+
 bool operator < (const WifiMode &a, const WifiMode &b)
 {
   return a.GetUid () < b.GetUid ();

src/wifi/model/wifi-mode.h

@@ -222,6 +222,18 @@ private:
  *         false otherwise
  */
 bool operator == (const WifiMode &a, const WifiMode &b);
+
+/**
+ * Check if the two WifiModes are different.
+ *
+ * \param a WifiMode
+ * \param b WifiMode
+ *
+ * \return true if the two WifiModes are different,
+ *         false otherwise
+ */
+bool operator != (const WifiMode &a, const WifiMode &b);
+
 /**
  * Compare two WifiModes
  *
@@ -232,6 +244,7 @@ bool operator == (const WifiMode &a, const WifiMode &b);
  *         false otherwise
  */
 bool operator < (const WifiMode &a, const WifiMode &b);
+
 /**
  * Serialize WifiMode to ostream (human-readable).
  *

src/wifi/model/yans-error-rate-model.cc

@@ -189,9 +189,9 @@ YansErrorRateModel::DoGetChunkSuccessRate (WifiMode mode, const WifiTxVector& tx
       || mode.GetModulationClass () == WIFI_MOD_CLASS_HE)
     {
       uint64_t phyRate;
-      if (txVector.IsMu () && (staId == SU_STA_ID))
+      if ((mode != txVector.GetMode ()) || (txVector.IsMu () && (staId == SU_STA_ID)))
         {
-          phyRate = mode.GetPhyRate (20); //This is the PHY header: consider 20 MHz to calculate the PHY rate
+          phyRate = mode.GetPhyRate (txVector.GetChannelWidth () >= 40 ? 20 : txVector.GetChannelWidth ()); //This is the PHY header
         }
       else
         {