A 4G phone is a type of cellular phone that can take advantage of the 4G wireless data network standard. 4G, which as of early 2010 is still under development and in the early stages of roll-out across the United States, is claimed by its developers to be capable of speeds two to four times faster than the current 3G cellular transmission standard. A 4G phone can access the Internet and wireless data services at peak gigabit, or mobile ultra-broadband, speeds.
To best understand the capabilities of a 4G phone, it helps to have some context relating to previous cellular standards. The first standard, known as 1G, provided only for simple analog voice transmissions sent along waveforms, rather than in digital packets. 1G phones suffered from the same kind of static and fading problems that automobile owners may experience when listening to AM or FM band radio, and could carry a maximum data transmission speed of only 14.4 kilobits per second (kbps).
The main issue with 1G, beyond unreliable call quality, was the relative inefficiency of analog transmissions compared to the space available on the cellular spectrum. Simply put, cellular providers were running out of room and, in order to add more customers, needed to switch to more efficient digital signals. This came about with the advent of the 2G standard. 2G phones operated using digital transmissions, and many could also take advantage of greatly enhanced data transmission speeds that averaged between 20 to 40 kbps.
Following up on the digital 2G standard, 3G was introduced around 2000, and provided users with a true mobile broadband experience. Data transmission speeds averaged between 500 and 700 kbps, or about the same as a home digital subscriber line (DSL) service. By the end of the decade, the technology had evolved to allow speeds averaging between one and three megabits per second (mbps). This final evolution of the standard has been unofficially labeled 3.5G.
The transmission standard behind the 4G phone is different from those that have come before it in one very important way — it is based entirely on Internet protocol (IP). This alone is a fundamental shift from the previous generations of cellular standards, and, in essence, means there is no limit to the number of voice or other types of communications that a 4G phone can handle at one time. Beyond the capacity for cable modem-type download speeds on a mobile device, 4G allows users to multi-task and talk on the phone while browsing the Internet and streaming video. 4G phones also have the ability to switch to 3G when out of range of 4G hubs, meaning little to no disruption of service for users.
This utility is best envisioned not by imagining a single 4G phone, but rather a 4G router serving an entire household's communication needs. Multiple computers, phones, and other mobile devices may all take advantage of a single 4G router, simultaneously and at gigabit speeds. This capability is intended to bring cellular technology to the level of traditional broadband services, such as DSL and cable.