This exmaple demonstrates the IEEE 802.11 rate control algorhitm.

The scenario contains two mobile nodes following each other around a 
thick wall that blocks the communication between the hosts when they
are on the opposite side. To follow how the data rate is changing, open 
the 'cliHost[0].wlan.mac' module and watch how the actual mode is changing
above the 'rateControl' module. The transmission rate will raise to 54Mbps
when the two nodes can see each other and quickly drop to 1Mbps once they
cannot communicate.
