Page 123 - Electronic Commerce

Chapter 2

One major advantage of Bluetooth technology is that it consumes very little power,
which is an important consideration for mobile devices. Another advantage is that
98 Bluetooth devices can discover one another and exchange information automatically. For
example, a person using a laptop computer in a temporary office can print to a local
Bluetooth-enabled printer without logging in to the network or installing software on
either device. The printer and the laptop computer electronically recognize each other as
Bluetooth devices and can immediately begin exchanging information.
Another wireless communication technology, Ultra Wideband (UWB), provides wide
bandwidth (up to about 480 Mbps in current versions) connections over short distances
(30 to 100 feet). UWB was developed for short-range secure communications in military
applications during the 1960s. Many observers believe that UWB technologies will be used
in future personal area networking applications such as home media centers (for example,
a PC could beam stored video files to a nearby television) and in linking mobile phones to
the Internet. UWB is faster and more reliable than the wireless Ethernet technologies now
used for these purposes.
A short-range wireless technology that was developed to be low cost and run on very
little power is ZigBee (the name is a reference to the waggle dance a honeybee performs
when returning to its hive). With intentionally low bandwidth (20–250 Kbps) to limit
power consumption, ZigBee has a range of 30 to 300 feet. An increasing number of
applications have been developed to run on ZigBee that control home energy management
systems (including lighting, heating, cooling), commercial building automation, security
systems, and remote controls for consumer electronic products. You can learn more about
this technology by visiting the ZigBee Alliance Web site.

Wireless Ethernet (Wi-Fi)
The most common wireless connection technology for use on LANs is called Wi-Fi,
wireless Ethernet,or 802.11n (802.11 is the number of the technology’s network
specification, which is the set of rules that equipment connected to the network must
follow). Wireless networking specifications are created by the IEEE (originally an
acronym for an organization named the Institute of Electrical and Electronic Engineers,
the letters are now used as the title of the organization and are pronounced eye-triple-E).
A computer equipped with a Wi-Fi network card can communicate through a wireless
access point connected to a LAN to become a part of that LAN. A wireless access point
(WAP) is a device that transmits network packets between Wi-Fi-equipped computers and
other devices that are within its range. The user must have authorization to connect to
the LAN and might be required to perform a login procedure before the laptop can access
the LAN through the WAP.
Wi-Fi that uses the 802.11n specification has a potential bandwidth of 450 Mbps and
a range of about 500 feet. In actual installations, the achieved bandwidth and range can
be dramatically affected by the construction material of the objects (such as walls, floors,
doors, and windows) through which the signals must pass. For example, reinforced
concrete walls and certain types of tinted glass windows greatly reduce the effective range
of Wi-Fi. Despite these limitations, organizations can make Wi-Fi a key element of their
LAN structures by installing a number of WAPs throughout their premises. The 802.11n

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