mobile phone history
Mobile rigs were the beginning of mobile phones for use in vehicles
such as taxicab radios, two way radios in police cruisers, and the
like. A large community of mobile radio users, known as the mobileers,
popularized the technology that would eventually give way to the mobile
phone. Originally, mobile phones were permanently installed in
vehicles, but later versions such as the so-called transportables or
"bag phones" were equipped with a cigarette lighter plug so that they
could also be carried, and thus could be used as either mobile or as
portable phones.
In December 1947, Douglas H. Ring and W. Rae Young, Bell Labs
engineers, proposed hexagonal cells for mobile phones.[1] Philip T.
Porter, also of Bell Labs, proposed that the cell towers be at the
corners of the hexagons rather than the centers and have directional
antennas that would transmit/receive in 3 directions (see picture at
left) into 3 adjacent hexagon cells.[2] [3] The technology did not
exist then and the frequencies had not yet been allocated. Cellular
technology was undeveloped until the 1960s, when Richard H. Frenkiel
and Joel S. Engel of Bell Labs developed the electronics.
In Europe, radio telephony was first used on the first-class passenger
trains between Berlin and Hamburg since 1926. At the same time, radio
telephony was introduced on passenger airplanes for air traffic
security. Later radio telephony was introduced on a large scale in
German tanks during the Second World War. After the war German police
in the British zone of occupation first used disused tank telephony
equipment to run the first radio patrol cars. In all of these cases the
service was confined to specialists that were trained to use the
equipment. In the early 1950s ships on the Rhine were among the first
to use radio telephony with an untrained end customer as a user.
Recognizable mobile phones with direct dialing have existed at least
since the 1950s. In the 1954 movie Sabrina, the businessman Linus
Larrabee (played by Humphrey Bogart) makes a call from the phone in the
back of his limousine.
The first fully automatic mobile phone system, called MTA (Mobile
Telephone system A), was developed by Ericsson and commercially
released in Sweden in 1956. This was the first system that didn't
require any kind of manual control, but had the disadvantage of a phone
weight of 40 kg (88 lbs). MTB, an upgraded version with transistors
(weighing "only" 9 kg / 8.6 lbs), was introduced in 1965 and used
dual-tone multifrequency signaling. It had 150 customers in the
beginning and 600 when it shut down in 1983.
In 1967, each mobile phone had to stay within the cell area serviced by
one base station throughout the phone call. This did not provide
continuity of automatic telephone service to mobile phones moving
through several cell areas. In 1970 Amos E. Joel, Jr., another Bell
Labs engineer,[4] invented an automatic "call handoff" system to allow
mobile phones to move through several cell areas during a single
conversation without loss of conversation.
In December 1971, AT&T submitted a proposal for cellular service to
the Federal Communications Commission (FCC). After years of hearings,
the FCC approved the proposal in 1982 for Advanced Mobile Phone Service
(AMPS) and allocated frequencies in the 824-894 MHz band.[5] Analog
AMPS was superseded by Digital AMPS in 1990.
One of the first truly successful public commercial mobile phone
networks was the ARP network in Finland, launched in 1971.
Posthumously, ARP is sometimes viewed as a zeroth generation (0G)
cellular network, being slightly above previous proprietary and limited
coverage networks.
Dr. Martin Cooper of Motorola, made the first US analogue mobile phone call on a larger prototype model in 1973.
First Generation Main article: 1G
The first handheld 1G mobile phone to become commercially available to
the US market was the Motorola DynaTAC 8000X, which received approval
in 1983. Mobile phones began to proliferate through the 1980s with the
introduction of "cellular" phones based on cellular networks with
multiple base stations located relatively close to each other, and
protocols for the automated "handover" between two cells when a phone
moved from one cell to the other. At this time analog transmission was
in use in all systems. Mobile phones were somewhat larger than current
ones, and at first, all were designed for permanent installation in
vehicles (hence the term car phone). Soon, some of these bulky units
were converted for use as "transportable" phones the size of a
briefcase. Motorola introduced the first truly portable, handheld
phone. These systems (NMT, AMPS, TACS, RTMI, C-Netz, and Radiocom 2000)
later became known as first generation (1G) mobile phones.
Second Generation Main articles: 2G, 2.5G, and 2.75G
In the 1990s, 'second generation' (2G) mobile phone systems such as
GSM, IS-136 ("TDMA"), iDEN and IS-95 ("CDMA") began to be introduced.
The first digital cellular phone call was made in the United States in
1990, in 1991 the first GSM network (Radiolinja) opened in Finland. 2G
phone systems were characterized by digital circuit switched
transmission and the introduction of advanced and fast phone to network
signaling. In general the frequencies used by 2G systems in Europe were
higher though with some overlap, for example the 900 MHz frequency
range was used for both 1G and 2G systems in Europe and so such 1G
systems were rapidly closed down to make space for 2G systems. In
America the IS-54 standard was deployed in the same band as AMPS and
displaced some of the existing analog channels.
Coinciding with the introduction of 2G systems was a trend away from
the larger "brick" phones toward tiny 100–200g hand-held devices, which
soon became the norm. This change was possible through technological
improvements such as more advanced batteries and more energy-efficient
electronics, but also was largely related to the higher density of
cellular sites caused by increasing usage levels.
Third Generation Main article: 3G
Not long after the introduction of 2G networks, projects began to
develop third generation (3G) systems. Inevitably there were many
different standards with different contenders pushing their own
technologies. Quite differently from 2G systems, however, the meaning
of 3G has been standardized in the IMT-2000 standardization processing.
This process did not standardize on a technology, but rather on a set
of requirements (2 Mbit/s maximum data rate indoors, 384 kbit/s
outdoors, for example). At that point, the vision of a single unified
worldwide standard broke down and several different standards have been
introduced.
During the development of 3G systems, 2.5G systems such as CDMA2000 1x
and GPRS were developed as extensions to existing 2G networks. These
provide some of the features of 3G without fulfilling the promised high
data rates or full range of multimedia services. CDMA2000-1X delivers
theoretical maximum data speeds of up to 307 kbit/s. Just beyond these
is the EDGE system which in theory covers the requirements for 3G
system, but is so narrowly above these that any practical system would
be sure to fall short.
At the beginning of the 21st century, 3G mobile phone systems such as
UMTS and CDMA2000 1xEV-DO have now begun to be publicly available. The
final success of these systems is still to be determined.
Live streaming of radio and television [2] to 3G handsets is one future
direction for the industry, with companies from Real [3] and Disney [4]
recently announcing services.
Subject: Mobile Abbreviations 
9/27/2007, 11:43 am
Some Electronics Components Definition 
