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

smartphones

, and wireless-enabled personal comput-

ers. We introduced smartphones in our discussions of the mobile digital

platform in Chapters 1 and 5. In addition to voice transmission, they feature

capabilities for e-mail, messaging, wireless Internet access, digital photography,

and personal information management. The features of the iPhone and

BlackBerry illustrate the extent to which cellphones have evolved into small

mobile computers.

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Part Two

Information Technology Infrastructure

CELLULAR SYSTEMS

Digital cellular service uses several competing standards. In Europe and much

of the rest of the world outside the United Sates, the standard is Global System

for Mobile Communication (GSM). GSM’s strength is its international roaming

capability. There are GSM cell phone systems in the United States, including T-

Mobile and AT&T Wireless.

The major standard in the United States is Code Division Multiple Access

(CDMA), which is the system used by Verizon and Sprint. CDMA was devel-

oped by the military during World War II. It transmits over several frequencies,

occupies the entire spectrum, and randomly assigns users to a range of

frequencies over time. 

Earlier generations of cellular systems were designed primarily for voice and

limited data transmission in the form of short text messages. Wireless carriers

now offer more powerful cellular networks called third-generation or 

3G

networks, with transmission speeds ranging from 144 Kbps for mobile users in,

say, a car, to more than 2 Mbps for stationary users. This is sufficient transmis-

sion capacity for video, graphics, and other rich media, in addition to voice,

making 3G networks suitable for wireless broadband Internet access. Many of

the cellular handsets available today are 3G-enabled.

High-speed cellular networks are widely used in Japan, South Korea, Taiwan,

Hong Kong, Singapore, and parts of northern Europe. In U.S. locations without

full 3G coverage, U.S. cellular carriers have upgraded their networks to support

higher-speed transmission, enabling cell phones to be used for Web access,

music downloads, and other broadband services. PCs equipped with a special

card can use these broadband cellular services for anytime, anywhere wireless

Internet access.

The next evolution in wireless communication, called