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310 Part Two Information Technology Infrastructure

The most popular use for Wi-Fi today is for high-speed wireless Internet
service. In this instance, the access point plugs into an Internet connection,
which could come from a cable service or DSL telephone service. Computers
within range of the access point use it to link wirelessly to the Internet.
Hotspots typically consist of one or more access points providing wireless
Internet access in a public place. Some hotspots are free or do not require any
additional software to use; others may require activation and the establishment
of a user account by providing a credit card number over the Web.
Businesses of all sizes are using Wi-Fi networks to provide low-cost wireless
LANs and Internet access. Wi-Fi hotspots can be found in hotels, airport lounges,
libraries, cafes, and college campuses to provide mobile access to the Internet.
Dartmouth College is one of many campuses where students now use Wi-Fi for
research, course work, and entertainment.
Wi-Fi technology poses several challenges, however. One is Wi-Fi’s security
features, which make these wireless networks vulnerable to intruders. We
provide more detail about Wi-Fi security issues in Chapter 8.
Another drawback of Wi-Fi networks is susceptibility to interference from
nearby systems operating in the same spectrum, such as wireless phones, micro-
wave ovens, or other wireless LANs. However, wireless networks based on the
802.11n standard are able to solve this problem by using multiple wireless anten-
nas in tandem to transmit and receive data and technology called MIMO (mul-
tiple input multiple output) to coordinate multiple simultaneous radio signals.

WiMax
A surprisingly large number of areas in the United States and throughout the
world do not have access to Wi-Fi or fixed broadband connectivity. The range of
Wi-Fi systems is no more than 300 feet from the base station, making it difficult
for rural groups that don’t have cable or DSL service to find wireless access to
the Internet.
The IEEE developed a new family of standards known as WiMax to deal
with these problems. WiMax, which stands for Worldwide Interoperability
for Microwave Access, is the popular term for IEEE Standard 802.16. It has a
wireless access range of up to 31 miles and transmission speed of up to 75 Mbps.
WiMax antennas are powerful enough to beam high-speed Internet connec-
tions to rooftop antennas of homes and businesses that are miles away. Cellular
handsets and laptops with WiMax capabilities are appearing in the marketplace.
Mobile WiMax is one of the 4G network technologies we discussed earlier in
this chapter.

RFID AND WIRELESS SENSOR NETWORKS

Mobile technologies are creating new efficiencies and ways of working through-
out the enterprise. In addition to the wireless systems we have just described,
radio frequency identification systems and wireless sensor networks are having
a major impact.

Radio Frequency Identification (RFID)
Radio frequency identification (RFID) systems provide a powerful technol-
ogy for tracking the movement of goods throughout the supply chain. RFID
systems use tiny tags with embedded microchips containing data about an item
and its location to transmit radio signals over a short distance to RFID read-
ers. The RFID readers then pass the data over a network to a computer for

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