HT configuration

================

HT is an acronym for High Throughput, a term synonymous with the IEEE 802.11n

standard.  Once the ``ns3::WifiHelper::Install`` has been called and the

user sets the standard to a variant that supports HT capabilities (802.11n,

802.11ac, or 802.11ax), an HT configuration object will automatically be

created for the device.  The configuration object is used to store and 

manage HT-specific attributes.

802.11n/ac PHY layer can use either either long (800 ns) or short (400 ns) OFDM guard intervals. To configure this parameter for a given device, the following lines of code could be used (in this example, it enables the support of a short guard interval for the first station)::

 Ptr<NetDevice> nd = wifiStaDevices.Get (0);

 Ptr<WifiNetDevice> wnd = nd->GetObject<WifiNetDevice> ();

 Ptr<HtConfiguration> htConfiguration = wnd->GetHtConfiguration ();

 htConfiguration->SetShortGuardIntervalSupported (true);

It is also possible to configure HT-specific attributes using ``Config::Set``.

The following line of code enables the support of a short guard interval for all stations:

 Config::Set ("/NodeList/*/DeviceList/*/$ns3::WifiNetDevice/HtConfiguration/ShortGuardIntervalSupported", BooleanValue (true));

Furthermore, 802.11n provides an optional mode (Greenfield mode) to reduce preamble durations and which is only compatible with 802.11n devices. This mode is enabled as follows::

 htConfiguration->SetGreenfieldSupported (true);

VHT configuration

=================

IEEE 802.11ac devices are also known as supporting Very High Throughput (VHT).  Once the ``ns3::WifiHelper::Install`` has been called and either the 802.11ac

or 802.11ax 5 GHz standards are configured, a VHT configuration object will be

automatically created to manage VHT-specific attributes.

As of ns-3.29, however, there are no VHT-specific configuration items to

manage; therefore, this object is a placeholder for future growth.

HE configuration

================

IEEE 802.11ax is also known as High Efficiency (HE).  Once the ``ns3::WifiHelper::Install`` has been called and IEEE 802.11ax configured as the standard, an 

HE configuration object will automatically be created to manage HE-specific

attributes for 802.11ax devices.

802.11ax PHY layer can use either either 3200 ns, 1600 ns or 800 ns OFDM guard intervals. To configure this parameter, the following line of code could be used (in this example, it enables the support of 1600 ns guard interval), such as in this example code snippet::

 Ptr<NetDevice> nd = wifiStaDevices.Get (0);

 Ptr<WifiNetDevice> wnd = nd->GetObject<WifiNetDevice> ();

 Ptr<HeConfiguration> heConfiguration = wnd->GetHeConfiguration ();

 heConfiguration->SetGuardInterval (NanoSeconds (1600));