Mobile phone
The
mobile phone (also called a mobile,
wireless, cellular phone, cell phone, or
hand phone(hp)is a short-range,
portable electronic device used for
mobile voice or data communication over
a network of specialized base stations
known as cell sites. In addition to the
standard voice function of a telephone,
current mobile phones may support many
additional services, and accessories,
such as SMS for text messaging, email,
packet switching for access to the
Internet,java gaming, bluetooth, infared,
camera with video recorder and MMS for
sending and receiving photos and video.
Most current mobile phones connect to a
cellular network of base stations (cell
sites), which is in turn interconnected
to the public switched telephone network
(PSTN) (the exception is satellite
phones). Since the mid-2000s, an
increasing number of cellphones can
connect to the Internet, a portion of
which can be navigated using cellphones.
In
1908, U.S. Patent 887,357 for a wireless
telephone was issued in to Nathan B.
Stubblefield of Murray, Kentucky. He
applied this patent to "cave radio"
telephones and not directly to cellular
telephony as the term is currently
understood.[59] Cells for mobile phone
base stations were invented in 1947 by
Bell Labs engineers at AT&T and further
developed by Bell Labs during the 1960s.
Radiophones have a long and varied
history going back to Reginald
Fessenden's invention and shore-to-ship
demonstration of radio telephony,
through the Second World War with
military use of radio telephony links
and civil services in the 1950s, while
hand-held cellular radio devices have
been available since 1973. Due to their
low establishment costs and rapid
deployment, mobile phone networks have
since spread rapidly throughout the
world, outstripping the growth of fixed
telephony.[citation needed]
In 1945, the zero generation (0G) of
mobile telephones was introduced. 0G
mobile phones, such as Mobile Telephone
Service, were not cellular, and so did
not feature "handover" from one base
station to the next and reuse of radio
frequency channels.[citation needed]
Like other technologies of the time, it
involved a single, powerful base station
covering a wide area, and each telephone
would effectively monopolize a channel
over that whole area while in use. The
concepts of frequency reuse and handoff
as well as a number of other concepts
that formed the basis of modern cell
phone technology are first described in
U.S. Patent 4,152,647 , issued May 1,
1979 to Charles A. Gladden and Martin H.
Parelman, both of Las Vegas, Nevada and
assigned by them to the United States
Government.
This is the first embodiment of all the
concepts that formed the basis of the
next major step in mobile telephony, the
Analog cellular telephone. Concepts
covered in this patent (cited in at
least 34 other patents) also were later
extended to several satellite
communication systems. Later updating of
the cellular system to a digital system
credits this patent.
Martin Cooper, a Motorola researcher and
executive is widely considered to be the
inventor of the first practical mobile
phone for handheld use in a non-vehicle
setting. Using a modern, if somewhat
heavy portable handset, Cooper made the
first call on a handheld mobile phone on
April 3, 1973.[60]
The first commercial citywide cellular
network was launched in Japan by NTT in
1979. Fully automatic cellular networks
were first introduced in the early to
mid 1980s (the 1G generation). The
Nordic Mobile Telephone (NMT) system
went online in Denmark, Finland, Norway
and Sweden in 1981[citation needed]. NMT
was the first mobile phone system that
enabled international use of the phone,
or "roaming" on other networks in other
countries. This was followed by a boom
in mobile phone usage, particularly in
Northern Europe.[citation needed]
In 1983, Motorola DynaTAC was the first
approved mobile phone by FCC in the
United States. In 1984, Bell Labs
developed modern commercial cellular
technology (based, to a large extent, on
the Gladden, Parelman Patent), which
employed multiple, centrally-controlled
base stations (cell sites), each
providing service to a small area (a
cell). The cell sites would be set up
such that cells partially overlapped. In
a cellular system, a signal between a
base station (cell site) and a terminal
(phone) only need be strong enough to
reach between the two, so the same
channel can be used simultaneously for
separate conversations in different
cells.
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