diff --git a/src/wifi/model/he-capabilities.cc b/src/wifi/model/he-capabilities.cc
index be8ddeb84..ae65a059b 100644
--- a/src/wifi/model/he-capabilities.cc
+++ b/src/wifi/model/he-capabilities.cc
@@ -93,7 +93,13 @@ HeCapabilities::HeCapabilities ()
 WifiInformationElementId
 HeCapabilities::ElementId () const
 {
-  return IE_HE_CAPABILITIES;
+  return IE_EXTENSION;
+}
+
+WifiInformationElementId
+HeCapabilities::ElementIdExt () const
+{
+  return IE_EXT_HE_CAPABILITIES;
 }
 
 void
@@ -107,7 +113,7 @@ HeCapabilities::GetInformationFieldSize () const
 {
   //we should not be here if ht is not supported
   NS_ASSERT (m_heSupported > 0);
-  return 16; //todo: variable length!
+  return 19; //todo: variable length!
 }
 
 Buffer::Iterator
@@ -140,8 +146,9 @@ HeCapabilities::SerializeInformationField (Buffer::Iterator start) const
       start.WriteU8 (GetHeMacCapabilitiesInfo2 ());
       start.WriteHtolsbU64 (GetHePhyCapabilitiesInfo1 ());
       start.WriteU8 (GetHePhyCapabilitiesInfo2 ());
-      start.WriteU16 (GetSupportedMcsAndNss ()); //todo: variable length
-      //todo: optional PPE Threshold field
+      start.WriteHtolsbU32 (GetSupportedMcsAndNss ());
+      //todo: add another 32-bits field if 160 MHz channel is supported (variable length)
+      //todo: optional PPE Threshold field (variable length)
     }
 }
 
@@ -153,11 +160,12 @@ HeCapabilities::DeserializeInformationField (Buffer::Iterator start, uint8_t len
   uint8_t macCapabilities2 = i.ReadU8 ();
   uint64_t phyCapabilities1 = i.ReadLsbtohU64 ();
   uint8_t phyCapabilities2 = i.ReadU8 ();
-  uint16_t mcsset = i.ReadU16 (); //todo: variable length
+  uint32_t mcsset = i.ReadU32 ();
   SetHeMacCapabilitiesInfo (macCapabilities1, macCapabilities2);
   SetHePhyCapabilitiesInfo (phyCapabilities1, phyCapabilities2);
   SetSupportedMcsAndNss (mcsset);
-  //todo: optional PPE Threshold field
+  //todo: add another 32-bits field if 160 MHz channel is supported (variable length)
+  //todo: optional PPE Threshold field (variable length)
   return length;
 }
 
diff --git a/src/wifi/model/he-capabilities.h b/src/wifi/model/he-capabilities.h
index 2e43ccd14..776ceb579 100644
--- a/src/wifi/model/he-capabilities.h
+++ b/src/wifi/model/he-capabilities.h
@@ -44,6 +44,11 @@ public:
    * \returns the wifi information element ID
    */
   WifiInformationElementId ElementId () const;
+  /**
+   * Get the wifi information element ID extension
+   * \returns the wifi information element ID extension
+   */
+  WifiInformationElementId ElementIdExt () const;
   /**
    * Get information field size
    * \returns the information field size
@@ -175,14 +180,14 @@ public:
   void SetHighestNssSupported (uint8_t nss);
 
   /**
-   * Is transmit MCS supported.
+   * Is RX MCS supported.
    *
    * \param mcs the MCS
    * \returns true if MCS transmit supported
    */
   bool IsSupportedTxMcs (uint8_t mcs) const;
   /**
-   * Is reeive MCS supported.
+   * Is RX MCS supported.
    *
    * \param mcs the MCS
    * \returns true if MCS receive supported
diff --git a/src/wifi/model/he-operation.cc b/src/wifi/model/he-operation.cc
index 1291cf46c..6247f80bf 100644
--- a/src/wifi/model/he-operation.cc
+++ b/src/wifi/model/he-operation.cc
@@ -40,7 +40,13 @@ HeOperation::HeOperation ()
 WifiInformationElementId
 HeOperation::ElementId () const
 {
-  return IE_HE_OPERATION;
+  return IE_EXTENSION;
+}
+
+WifiInformationElementId
+HeOperation::ElementIdExt () const
+{
+  return IE_EXT_HE_OPERATION;
 }
 
 void
@@ -54,7 +60,7 @@ HeOperation::GetInformationFieldSize () const
 {
   //we should not be here if he is not supported
   NS_ASSERT (m_heSupported > 0);
-  return 10;
+  return 7;
 }
 
 void
@@ -91,10 +97,23 @@ void
 HeOperation::SetMaxHeMcsPerNss (uint8_t nss, uint8_t maxHeMcs)
 {
   NS_ASSERT ((maxHeMcs >= 7 && maxHeMcs <= 11) && (nss >= 1 && nss <= 8));
-  m_basicHeMcsAndNssSet |= (((maxHeMcs - 7) & 0x07) << ((nss - 1) * 3));
+  uint8_t val = 3; //3 means not supported
+  if (maxHeMcs > 9) //MCS 0 - 11
+    {
+      val = 2;
+    }
+  else if (maxHeMcs > 7) //MCS 0 - 9
+    {
+      val = 1;
+    }
+  else if (maxHeMcs == 7) //MCS 0 - 7
+    {
+      val = 0;
+    }
+  m_basicHeMcsAndNssSet |= ((val & 0x03) << ((nss - 1) * 2));
 }
 
-uint32_t
+uint16_t
 HeOperation::GetBasicHeMcsAndNssSet (void) const
 {
   return m_basicHeMcsAndNssSet;
@@ -127,11 +146,8 @@ HeOperation::SerializeInformationField (Buffer::Iterator start) const
     {
       //write the corresponding value for each bit
       start.WriteHtolsbU32 (GetHeOperationParameters ());
-      uint32_t mcsset = GetBasicHeMcsAndNssSet ();
-      start.WriteU16 (mcsset & 0xffff);
-      start.WriteU8 ((mcsset >> 16) & 0xff);
-      start.WriteU16 (0); //todo: VHT Operation Information
-      start.WriteU8 (0); //todo: VHT Operation Information
+      start.WriteU16 (GetBasicHeMcsAndNssSet ());
+      //todo: VHT Operation Information (variable)
     }
 }
 
@@ -140,13 +156,9 @@ HeOperation::DeserializeInformationField (Buffer::Iterator start, uint8_t length
 {
   Buffer::Iterator i = start;
   uint32_t heOperationParameters = i.ReadLsbtohU32 ();
-  uint16_t mcsset_1 = i.ReadU16 ();
-  uint8_t mcsset_2 = i.ReadU8 ();
-  i.ReadU16 (); //todo: VHT Operation Information
-  i.ReadU8 (); //todo: VHT Operation Information
+  m_basicHeMcsAndNssSet = i.ReadU16 ();
   SetHeOperationParameters (heOperationParameters);
-  m_basicHeMcsAndNssSet |= mcsset_1 & 0xffff;
-  m_basicHeMcsAndNssSet |= (mcsset_2 & 0xff) << 16;
+  //todo: VHT Operation Information (variable)
   return length;
 }
 
diff --git a/src/wifi/model/he-operation.h b/src/wifi/model/he-operation.h
index 17150279a..2caf16b8d 100644
--- a/src/wifi/model/he-operation.h
+++ b/src/wifi/model/he-operation.h
@@ -71,7 +71,7 @@ public:
    *
    * \return the Basic HE-MCS And Nss field in the HE Operation information element
    */
-  uint32_t GetBasicHeMcsAndNssSet (void) const;
+  uint16_t GetBasicHeMcsAndNssSet (void) const;
 
   /**
    * Return the element ID.
@@ -79,6 +79,11 @@ public:
    * \returns the element ID
    */
   WifiInformationElementId ElementId () const;
+  /**
+   * Get the wifi information element ID extension
+   * \returns the wifi information element ID extension
+   */
+  WifiInformationElementId ElementIdExt () const;
   /**
    * Return the information field size.
    *
@@ -131,7 +136,7 @@ private:
   uint8_t m_dualBeacon; //!< Dual Beacon
 
   //Basic HE-MCS and NSS Set
-  uint32_t m_basicHeMcsAndNssSet; ///< basic HE MCS NSS set
+  uint16_t m_basicHeMcsAndNssSet; ///< basic HE MCS NSS set
 
   //TODO: VHT Operation Information subfields not defined in the standard yet.
 
diff --git a/src/wifi/model/wifi-information-element.cc b/src/wifi/model/wifi-information-element.cc
index bea446576..5a7dff5ad 100644
--- a/src/wifi/model/wifi-information-element.cc
+++ b/src/wifi/model/wifi-information-element.cc
@@ -37,13 +37,28 @@ WifiInformationElement::GetSerializedSize () const
   return (2 + GetInformationFieldSize ());
 }
 
+WifiInformationElementId
+WifiInformationElement::ElementIdExt () const
+{
+  return 0;
+}
+
 Buffer::Iterator
 WifiInformationElement::Serialize (Buffer::Iterator i) const
 {
   i.WriteU8 (ElementId ());
   i.WriteU8 (GetInformationFieldSize ());
-  SerializeInformationField (i);
-  i.Next (GetInformationFieldSize ());
+  if (ElementId () == IE_EXTENSION)
+    {
+      i.WriteU8 (ElementIdExt ());
+      SerializeInformationField (i);
+      i.Next (GetInformationFieldSize () - 1);
+    }
+  else
+    {
+      SerializeInformationField (i);
+      i.Next (GetInformationFieldSize ());
+    }
   return i;
 }
 
@@ -77,10 +92,24 @@ WifiInformationElement::DeserializeIfPresent (Buffer::Iterator i)
     }
 
   uint8_t length = i.ReadU8 ();
-
-  DeserializeInformationField (i, length);
-  i.Next (length);
-
+  if (ElementId () == IE_EXTENSION)
+  {
+    uint8_t elementIdExt = i.ReadU8 ();
+    //If the element here isn't the one we're after then we immediately
+    //return the iterator we were passed indicating that we haven't
+    //taken anything from the buffer.
+    if (elementIdExt != ElementIdExt ())
+      {
+        return start;
+      }
+    DeserializeInformationField (i, length - 1);
+    i.Next (length - 1);
+  }
+  else
+  {
+    DeserializeInformationField (i, length);
+    i.Next (length);
+  }
   return i;
 }
 
@@ -97,6 +126,11 @@ WifiInformationElement::operator== (WifiInformationElement const & a) const
       return false;
     }
 
+  if (ElementIdExt () != a.ElementIdExt ())
+    {
+      return false;
+    }
+
   uint32_t ieSize = GetInformationFieldSize ();
 
   Buffer myIe, hisIe;
diff --git a/src/wifi/model/wifi-information-element.h b/src/wifi/model/wifi-information-element.h
index c9c57b574..59e822a5b 100644
--- a/src/wifi/model/wifi-information-element.h
+++ b/src/wifi/model/wifi-information-element.h
@@ -185,10 +185,11 @@ typedef uint8_t WifiInformationElementId;
 #define IE_OPERATING_MODE_NOTIFICATION          ((WifiInformationElementId)199)
 // 200 to 220 are reserved
 #define IE_VENDOR_SPECIFIC                      ((WifiInformationElementId)221)
-// 222 to 255 are reserved
-#define IE_HE_CAPABILITIES                      ((WifiInformationElementId)255) //todo: not defined yet in the standard!
-#define IE_HE_OPERATION                         ((WifiInformationElementId)255) //todo: not defined yet in the standard!
+// 222 to 254 are reserved
+#define IE_EXTENSION                            ((WifiInformationElementId)255)
 
+#define IE_EXT_HE_CAPABILITIES                  ((WifiInformationElementId)35)
+#define IE_EXT_HE_OPERATION                     ((WifiInformationElementId)36)
 
 /**
  * \brief Information element, as defined in 802.11-2007 standard
@@ -303,6 +304,11 @@ public:
   virtual uint8_t DeserializeInformationField (Buffer::Iterator start,
                                                uint8_t length) = 0;
 
+  /**
+   * \returns Own unique Element ID Extension
+   */
+  virtual WifiInformationElementId ElementIdExt () const;
+
   // In addition, a subclass may optionally override the following...
   /**
    * Generate human-readable form of IE