/**

 * \defgroup Wifi Wifi Models

 *

 * \section Wifi Models

 *

 * The set of 802.11 models provided in ns-3 attempts to provide

 * an accurate MAC-level implementation of the 802.11 specification

 * and to provide a not-so-slow PHY-level model of the 802.11a

 * specification.

 *

 * The current implementation provides roughly 4 levels of models:

 *   - the PHY layer models

 *   - the so-called MAC low models: they implement DCF

 *   - the so-called MAC high models: they implement the MAC-level

 *     beacon generation, probing, and association state machines.

 *   - a set of Rate control algorithms used by the MAC low models.

 * 

 *

 * We have today 3 MAC high models:

 *   - a simple adhoc state machine which does not perform any

 *     kind of beacon generation, probing, or association. This

 *     state machine is implemented by the ns3::AdhocWifiNetDevice

 *     class.

 *   - an active probing and association state machine which handles

 *     automatic re-association whenever too many beacons are missed

 *     is implemented by the ns3::NqstaWifiNetDevice class.

 *   - an access point which generates periodic beacons, and which

 *     accepts every attempt to associate. This AP state machine

 *     is implemented by the ns3::NqapWifiNetDevice.

 *

 * The MAC low layer is split in 3 components:

 *   - ns3::MacLow which takes care of RTS/CTS/DATA/ACK transactions.

 *   - ns3::Dcf which implements the DCF function.

 *   - ns3::DcaTxop which handles the packet queue, packet fragmentation,

 *     and packet retransmissions if they are needed.

 *

 * The PHY layer implements a single model in ns3::WifiPhy.

 *

 * It also provides a set of Rate control algorithms:

 *   - ns3::ArfMacStations (initialized from \valueref{WifiArfTimerThreshold}, and,

 *     \valueref{WifiArfSuccessThreshold})

 *   - ns3::AArfMacStations (initialized from \valueref{WifiAarfMinSuccessThreshold},

 *     \valueref{WifiAarfMinTimerThreshold}, \valueref{WifiAarfSuccessK}, 

 *     \valueref{WifiAarfMaxSuccessThreshold}, and, \valueref{WifiAarfTimerK}

 *   - ns3::IdealMacStations (initialized from \valueref{WifiIdealRateControlBerThreshold})

 *   - ns3::CrMacStations (initialized from \valueref{WifiConstantDataRate}, and,

 *     \valueref{WifiConstantCtlRate}).

 *

 * The type of rate control algorithm is controlled through \valueref{WifiRateControlAlgorithm}.

 *

 *

 * \section Wifi Tutorial

 *

 *

 */