History of First-Generation Systems

Mobile communications as we know it today really started in the late 1970s,
with the implementation of a trial system in Chicago in 1978. The system
used a technology known as Advanced Mobile Phone Service (AMPS), operating
in the 800-MHz band. For numerous reasons, however, including the
break-up of AT&T, it took a few years before a commercial system was
launched in the United States. That launch occurred in Chicago in 1983,
with other cities following rapidly.
Meanwhile, however, other countries were making progress, and a commercial
AMPS system was launched in Japan in 1979. The Europeans also
were active in mobile communications technology, and the first European
system was launched in 1981 in Sweden, Norway, Denmark, and Finland.
The European system used a technology known as Nordic Mobile Telephony
(NMT), operating in the 450-MHz band. Later, a version of NMT was developed
to operate in the 900-MHz band and was known (not surprisingly) as
NMT900. Not to be left out, the British introduced yet another technology in 1985. This technology is known as the Total Access Communications System
(TACS) and operates in the 900-MHz band. TACS is basically a modified
version of AMPS.
Many other countries followed along, and soon mobile communications
services spread across the globe. Although several other technologies were
developed, particularly in Europe, AMPS, NMT (both variants), and TACS
were certainly the most successful technologies. These are the main firstgeneration
systems and they are still in service today.
First-generation systems experienced success far greater than anyone
had expected. In fact, this success exposed one of the weaknesses in the
technologies—limited capacity. Of course, the systems were able to handle
large numbers of subscribers, but when the subscribers started to number
in the millions, cracks started to appear, particularly since subscribers tend
to be densely clustered in metropolitan areas. Limited capacity was not the
only problem, however, and other problems such as fraud became a major
concern. Consequently, significant effort was dedicated to the development
of second-generation systems.