Information Technology Reference
In-Depth Information
The
FAX
Profile
is similar to the DUNP profile, enabling wireless fax
machines to send and receive faxes using mobile phones.
The
Intercom Profile
(IP) allows two phones to connect as transceivers.
The
Headset Profile
(HSP) allows a headset to connect its base station.
The
Object Push Profile
(OPP), the
File Transfer Profile
(FTP), and the
Synchronization Profile
(SP) are devoted to the objects exchange between
two wireless devices. Objects could be electronic business cards, pictures
or data files. The SP profile, in particular, is designed to synchronize data
between two devices, such as the phonebook of a PDA and a PC.
3
Wi-Fi
Wi-Fi (wireless fidelity) is currently the most used technology to implement
wireless local area networks (WLANs). It is defined by the IEEE 802.11x
standard [7].
802.11 WLANs are based on a cellular architecture in which the area
where the service should be available is divided into cells, as well as in the
GSM telephony networks. Each cell (called basic service set, BSS) is
controlled by a base station also known as access point (AP) [8]. An AP is
similar to a network hub, relaying data between connected wireless devices in
addition to a (usually) single connected wired device, most often an ethernet
hub or switch, allowing wireless devices to communicate with other wired
devices. This is the
infrastructure
operational mode (Figure 7). Even if a
simple wireless LAN can be composed of a single cell with a single access
point, in most cases, there will be a number of cells in which access points
are interconnected through some type of distribution network (which is
usually defined
distribution system
or DS). A set of several interconnected
WLANs, including various cells, the corresponding access points and the
Figure 7: Wi-Fi WLAN - Infrastructure mode, single cell (BSS).
