Wireless devices are increasingly common -- In fact, there were 331.6 million wireless subscriber connections in the United States at the end of 2011 -- more than the entire U.S. population, according to CTIA, the International Association for the Wireless Telecommunications Industry. The traditional cell phone grid is not the only type of wireless network, however. Since the introduction of digital cell phones in the 1990s, a variety of network formats have been developed. Users can choose from several wireless access methods to talk, text, and connect to the Internet.
2G is a digital wireless access method used by basic cellular telephones. The name comes from the term "second generation," and indicates that 2G is an upgrade from the outdated analog connection method. Prior to the introduction of 2G wireless in the early 1990s, cellphones were not digital. The radio signal of a first-generation analog phone could be easily intercepted by anybody listening on the same frequency. 2G digital signals are much more secure and have significantly better sound quality. This type of wireless signal is not designed to transfer large amounts of data, and is best suited for standard voice calls and simple text messages. In order to allow many different phones to share the same frequencies, CDMA and GSM standards were developed. In basic terms, CDMA and GSM signals are sent using a variety of digital languages, or "codes." Some of the cell phones in an area utilize one code, while other phones communicate with a completely different code. This prevents 2G phones from "interrupting" each other. As of the date of publication, the 2G format is still used by many basic cell phones, although it is slowly being replaced by newer technology.
3G or "third generation" wireless access is designed to transfer data at a faster rate than the older 2G system. This speed upgrade occurred in several steps. In the year 2000, cell phone companies began to implement General Packet Radio Service, or "GPRS." This was the beginning of 3G service, and allowed wireless data speeds of up to 114 kbps. Enhanced Data Rates for Global Evolution, also called "EDGE," was implemented in 2003. This improved the transfer rate for 3G devices to 384 kbps. Several other upgrades have since raised the rate of 3G wireless to over 1 Mbps in many developed countries. These speeds allow smartphones, including the BlackBerry and iPhone, to browse the Web and send multimedia messages. 3G can also be used to wirelessly connect tablet computers and laptops to the Internet.
4G is the "fourth generation" of mobile wireless technology. According to the International Telecommunication Union, a network is considered 4G if it operates at 100 Mbps or faster. This is more than 25 times faster than the previous 3G format. 4G wireless networks are fast enough to replace traditional cable-based broadband Internet connections, and can be used by both home computer and mobile smartphone users. 4G is significantly different from 3G -- it's not just an "upgraded" version of the older technology. A 4G network uses orthogonal frequency division multiplexing, or "OFDM." This means that the signal is split into several distinct sub-signals with slightly different frequencies. 4G was first launched in the United States in 2008. Large cities were the first to receive fourth-generation service. Major U.S. carriers plan to extend the wireless coverage -- meaning that 4G speeds eventually will be available throughout most of the country.
Wi-Fi is a type of wireless signal designed for local networks. A Wireless Local Area Network, or "WLAN," typically covers an office building or a home and does not extend beyond a relatively short range. A Wi-Fi wireless network allows a group of users to share files and connect to the Internet without a hard-wired network cable. There are several varieties of Wi-Fi, each defined by the Institute of Electrical and Electronics Engineers (IEEE). The 802.11b Wi-Fi format operates on a radio frequency of 2.4 GHz and has a maximum speed of 11 Mbps. 802.11g was released in 2003 and increased the maximum Wi-Fi speed to 54 Mbps. In 2009, the 802.11n wireless standard was announced -- it significantly upgraded the rate, to 600 Mbps. Wi-Fi networks can be used to connect PCs, smartphones, and tablet computers to the Internet; they typically have a range of several hundred feet.
Bluetooth is a wireless networking technology intended for small, personal networks. A short-range Bluetooth network is sometimes called a Personal Area Network, "PAN," or "piconet." While cell phone and Wi-Fi networks provide connectivity for many simultaneous users, a Bluetooth connection is typically used by only one user. Small Bluetooth radios are integrated in many electronic devices, ranging from music players to smartphones and printers. Wireless Bluetooth can replace the tangle of cords that these devices traditionally require. For example, a Bluetooth-enabled smartphone can be controlled by a wireless keyboard while also connecting to the user's headset for incoming calls. Bluetooth devices must be "paired" or linked before use -- this prevents unauthorized people from connecting to the personal network.
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