CELLULAR COMMUNICATIONS has become an essential facet of life for most people. But those of the "older generations" can certainly remember a time without cellular telephonesin popular culture, think back to Clark Kent racing into a telephone booth to change into Superman. Today, the telephone booth has become a technological victim of the cell phone.
Portable two-way communications has been available in the form of hand-held radio transceivers used for military radio telephone links since World War II. Motorola did a great deal of development work for the US Army, producing walkie-talkies and two-way radios. The firm's two-way "Handie-Talkie" was large compared to modern cellular telephones, but reliable. A simple mobile communications service, the Mobile Telephone Service, was introduced in St. Louis, MO in 1946. But it only had three channels, and voice channels were limited per area.
The modern concept of breaking areas into communications cells was first proposed by Bell Laboratories engineers Douglas Ring and W. Rae Young in 1947. Their idea was to use hexagonal-shaped cells with antennas in the center of the hexagon. Bell Labs' Philip Porter added the modification of having cell towers with antennas at the corners of the hexagon for improved radio coverage. But it would not be until the 1960s when the technology existed to implement such a system.
All of these early cellular system concepts assumed that a user would remain in the cell in which the call was initiated. The concepts of moving between cells did not emerge until 1970. Bell Labs engineer Amos Joel, Jr. invented an automatic call handoff system to allow mobile phones to move between cells during a call. In 1971, Bell Labs' parent company, AT&T, would submit a proposal for cellular service to the United States Federal Communications Commission (FCC). But it wasn't until 1982, after years of hearings, that the FCC would approve the proposal, granting AT&T permission to use allocated frequencies in the 824 to 894 MHz band for their Advanced Mobile Phone System (AMPS) cellular technology.
The first analog mobile telephone call in the US was made by Motorola researcher Marty Cooper, who called Dr. Joel Engel of Bell Labs. Cooper is credited as the first inventor of a portable mobile phone (US Patent No. 3,906,166). The first automated commercial cellular network representing the first-generation (1G) of cellular communications technology was launched by NTT in Japan in 1979. The network consisted of 23 base stations in an area with over 20 million people (Tokyo). The network would expand to cover all of Japan and become the first nationwide 1G cellular network. In 1981, the Nordic Mobile Telephone (NMT) 1G cell system launched in Denmark, Finland, Norway, and Sweden.
In the 1990s, the analog technology of 1G cellular systems would be replaced by the digital technology of second-generation (2G) cellular systems, largely based on the Global System for Mobile Communications (GSM) standard. The 2G networks employed digital technologies such as code-division-multiple-access (CDMA) techniques to support more users per cell.
As the desire by cellular phone users to access the Internet grew, it became clear that there was a need for a third-generation (3G) of cellular networkone that could provide Internet access. In 2001, Japan's NTT DoCoMo launched the first commercial 3G network, based on wideband CDMA (WCDMA). By the end of 2002, Vodafone KK launched the second WCDMA network in Japan, and 3G networks would spread around the world.
With a growing desire for more Internet- based services, it became apparent that data-optimized fourth-generation (4G) networks would be needed. By eliminating 3G's circuit switching and relying on an all-Internet-Protocol (all-IP) network, 4G network solutions such as Long Term Evolution (LTE) and WiMAX promise greater speed as the current 4G cellular network buildup continues.