Kenneth C. Laudon,Jane P. Laudon Management Information System 12th Edition pdf

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. 

FIGURE 7-16

AN 802.11 WIRELESS LAN

Mobile laptop computers equipped with network interface cards link to the wired LAN by communi-

cating with the access point. The access point uses radio waves to transmit network signals from the

wired network to the client adapters, which convert them into data that the mobile device can

understand. The client adapter then transmits the data from the mobile device back to the access

point, which forwards the data to the wired network.

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Chapter 7

Telecommunications, the Internet, and Wireless Technology

279

Another drawback of Wi-Fi networks is susceptibility to interference from

nearby systems operating in the same spectrum, such as wireless phones,

microwave ovens, or other wireless LANs. However, wireless networks based on

the 802.11n standard are able to solve this problem by using multiple wireless

antennas in tandem to transmit and receive data and technology called 

MIMO

(multiple input multiple output) to coordinate multiple simultaneous radio signals. 

W i M a x

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 pre-4G network technologies we discussed earlier

in this chapter. Clearwire, which is owned by Sprint-Nextel, is using WiMax

technology as the foundation for the 4G networks it is deploying throughout the

United States. 

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. 

R a d i o   F r e q u e n c y   I d e n t i f i c a t i o n   ( R F I D )