Cellular Systems

Today 81 percent of U.S. adults own mobile phones, and 69 percent own smart­phones (eMarketer, 2018). Mobile is now the leading digital platform, with total activity on smartphones and tablets accounting for two-thirds of digital media time spent, and smartphone apps alone capturing more than half of digital media time (Comscore, 2017).

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 Communications (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.

A competing standard in the United States is Code Division Multiple Access (CDMA), which is the system Verizon and Sprint use. CDMA was developed 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, making it more efficient than GSM.

Earlier generations of cellular systems were designed primarily for voice and limited data transmission in the form of short text messages. Today wireless carriers offer 3G and 4G networks. 3G networks, with transmission speeds ranging from 144 Kbps for mobile users in, say, a car, to more than 2 Mbps for stationary users, offer transmission speeds appropriate for email and web browsing, but are too slow for videos. 4G networks have much higher speeds, up to 100 Mbps download and 50 Mbps upload, with more than enough capacity for watching high-definition video on your smartphone. Long Term Evolution (LTE) and mobile Worldwide Interoperability for Microwave Access (WiMax— see the following section) are the current 4G standards.

The next generation of wireless technology, called 5G, is still under devel­opment. 5G will support transmission of huge amounts of data in the gigabit range, with fewer transmission delays and the ability to connect many more devices (such as sensors and smart devices) at once than existing cellular sys­tems. 5G technology will be needed for self-driving vehicles, smart cities, and extensive use of the Internet of Things. AT&T, Verizon, and other carriers are starting to launch 5G networks.

Source: Laudon Kenneth C., Laudon Jane Price (2020), Management Information Systems: Managing the Digital Firm, Pearson; 16^th edition.