Local Area Connectivity

Now let’s consider local area connectivity—for instance, a person in an airport. If a person
is using a laptop to download a file, he will be more or less stationary. This is
defined as a portable application rather than a mobile application. If the user does
move, it will be a relatively slow move (walking from area to area), which will be relatively
easy to track. There is less need for a sophisticated and bandwidth-hungry signaling
overlay. In addition, because the user is inside and probably close to a base
station, there will be little or no multipath to worry about, so much of the channel coding
needed for wide area coverage can be discarded.
An optimized air interface can therefore be produced to support portable local area
access connectivity without the bandwidth overheads and delay overheads associated
with a wide area mobility air interface. This is the thinking behind wireless LANs
(WLANs). Table 15.1 summarizes present wireless LAN standards and typical gross
and net data rates.