Page 67 - DCAP311_DCAP607_WIRELESS_NETWORKS

Unit 4: Wireless Networks Types and PAN Technologies

Notes
Example: An archeologist on site in Greece might use a PDA to directly access databases
at the University of Minnesota in Minneapolis, and to transmit findings to that database.

z z Bluetooth: Bluetooth uses short-range radio waves over distances up to approximately 10
metres. For example, Bluetooth devices such as a keyboards, pointing devices, audio head
sets, printers may connect to personal digital assistants (PDAs), cell phones, or computers
wirelessly.
A Bluetooth PAN is also called a piconet (combination of the prefix “pico,” meaning very
small or one trillionth, and network), and is composed of up to 8 active devices in a master-
slave relationship (a very large number of devices can be connected in “parked” mode).
The first Bluetooth device in the piconet is the master, and all other devices are slaves that
communicate with the master. A piconet typically has a range of 10 metres (33 ft), although
ranges of up to 100 metres (330 ft) can be reached under ideal circumstances.

z z Infrared Data Association: Infrared Data Association (IrDA) uses infrared light, which has
a frequency below the human eye’s sensitivity. Infrared in general is used, for instance, in
TV remotes. Typical WPAN devices that use IrDA include printers, keyboards, and other
serial data interfaces.

z z WiFi: WiFi uses radio waves for connection over distances up to around 91 metres, usually
in a local area network (LAN) environment. Wifi can be used to connect local area networks,
to connect cellphones to the Internet to download music and other multimedia, to allow PC
multimedia content to be stream to the TV (Wireless Multimedia Adapter), and to connect
video game consoles to their networks (Nintendo WiFi Connection).

z z Body area network: A body area networks is based on the IEEE 802.15.6 standard for
transmission via the capacitive near field of human skin allowing near field communication
of devices worn by and near the wearer. The Skinplex implementation can detect and
communicate up to 1 metre (3 ft 3 in) from a human body. It is used for access control to
door locks and jamming protection in convertible car roofs.

4.1.2 WLAN (Wireless Local Area Network)

WLAN on the other is more focused on organizational connectivity not unlike wire based LAN
connections. The intent of WLAN technologies is to provide members of workgroups access to
corporate network resources be it shared data, shared applications or e-mail but do so in way that
does not inhibit a user’s mobility. The emphasis is on a permanence of the wireless connection
within a defined region like an office building or campus. This implies that there are wireless
access points that define a finite region of coverage.

Wireless local area networks (WLANs) are the same as the traditional LAN but they have a
wireless interface. With the introduction of small portable devices such as PDAs (personal digital
assistants), the WLAN technology is becoming very popular. WLANs provide high speed data
communication in small areas such as a building or an office. It allows users to move around in a
confined area while they are still connected to the network.

Example: of wireless LAN that are available today are NCR’s waveLAN and Motorola’s
ALTAIR.

Transmission Technology

There are three main ways by which WLANs transmit information : microwave, spread spectrum
and infrared.

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