MOBILE PHONE
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A mobile or cellular telephone is a long-range, portable
electronic device for personal telecommunications over long distances.
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 are satellite phones). Cellular networks were first
introduced in the early to mid 1980s (the 1G generation). Prior mobile phones
operating without a cellular network (the so-called 0G generation), such as
Mobile Telephone Service, date back to 1945. Until the mid to late 1980s, most
mobile phones were sufficiently large that they were permanently installed in
vehicles as car phones. With the advance of miniaturization, currently the vast
majority of mobile phones are handheld. In addition to the standard voice
function of a telephone, a mobile phone can support many additional services
such as SMS for text messaging, email, packet switching for access to the
Internet, and MMS for sending and receiving photos and video.
The world's largest mobile phone manufacturers include Audiovox, BenQ-Siemens,
High Tech Computer Corporation, Fujitsu, Kyocera, LG, Motorola, NEC, Nokia,
Panasonic (Matsushita Electric), Pantech Curitel, Philips, Sagem, Samsung, Sanyo,
Sharp, Siemens SK Teletech, Sony Ericsson, T&A Alcatel, and Toshiba.
The world's largest mobile phone operators (based on customer totals) include
China Mobile, Vodafone, and China Unicom.
There are also specialist communication systems related to, but distinct from
mobile phones, such as Professional Mobile Radio. Mobile phones are also
distinct from cordless telephones, which generally operate only within a limited
range of a specific base station. Technically, the term mobile phone includes
such devices as satellite phones and pre-cellular mobile phones such as those
operating via MTS which do not have a cellular network, whereas the related term
cell(ular) phone does not. In practice, the two terms are used nearly
interchangeably, with the preferred term varying by location.
History and Development of the Cell Phone
Dr. Marty Cooper is widely considered to be the inventor of the cell phone. Using a modern, if somewhat heavy portable handset, Cooper made the first call on a cell phone in 1973. At the time he made his call, Cooper was working as Motorola's General Manager of its Communications Division. Motorola had developed the idea of using cellular communications on a portable platform (i.e., a handset)in a non-vehicle setting.
Worldwide deployment
Radio phones have a long and varied history that stretches back
to the 1950s, with hand-held cellular radio devices being available since 1983.
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.
World mobile phone usageIn most of Europe, wealthier parts of Asia, Africa, the
Caribbean, Latin America, Australia, Canada, and the United States, mobile
phones are now widely used, with the majority of the adult, teenage, and even
child population owning one. Taiwan had the highest mobile phone usage in 2005
at 111 subscribers per 100 people. Hong Kong has the highest mobile phone
penetration rate in the world, at 127.4% in June 2006. The total number of
mobile phone subscribers in the world was estimated at 2.14 billion in 2005.
Around 80% of world's population have mobile phone coverage as of 2006. This
figure is expected to increase to 90% by the year 2010.
At present, Africa has the largest growth rate of cellular subscribers in the
world. African markets are expanding nearly twice as fast as Asian markets. The
availability of Prepaid or pay as you go services, where the subscriber does not
have to commit to a long term contract, has helped fuel this growth on a
monumental scale, not only in Africa but on other continents as well.
All European nations and most Asian and African nations have adopted GSM. In
other countries, such as the United States, Australia, Japan, and South Korea,
legislation does not require any particular standard, and GSM coexists with
other standards, such as CDMA and iDEN.
Mobile phone culture or customs
In fewer than twenty years, mobile phones have gone from being
rare and expensive pieces of equipment used by businesses to a pervasive low-cost
personal item. In many countries, mobile phones now outnumber land-line
telephones, with most adults and many children now owning mobile phones . In the
United States, 50% of children own mobile phones. It is not uncommon for young
adults to simply own a mobile phone instead of a land-line for their residence .
In some developing countries, where there is little existing fixed-line
infrastructure, the mobile phone has become widespread. According to the CIA
World Factbook the UK now has more mobile phones than people.
With high levels of mobile telephone penetration, a mobile culture has evolved,
where the phone becomes a key social tool, and people rely on their mobile phone
address book to keep in touch with their friends. Many people keep in touch
using SMS, and a whole culture of "texting" has developed from this. The
commercial market in SMS's is growing. Many phones even offer Instant Messenger
services to increase the simplicity and ease of texting on phones. Cellular
phones in Japan, offering Internet capabilities such as NTT DoCoMo's i-mode,
offer text messaging via standard e-mail.
The mobile phone itself has also become a totemic and fashion object, with users
decorating, customizing, and accessorizing their mobile phones to reflect their
personality. This has emerged as its own industry. The sale of commercial
ringtones exceeded $2.5 billion in 2004.
The use of a mobile phone is prohibited in some rail carriagesMobile phone
etiquette has become an important issue with mobiles ringing at funerals,
weddings, movies, and plays. Users often speak at increased volume which has led
to places like bookshops, libraries, movie theatres, doctor's offices, and
houses of worship posting signs prohibiting the use of mobile phones, and in
some places installing signal jamming equipment to prevent usage (although in
many countries, e.g. the United States, such equipment is illegal).
Transportation providers, particularly those doing long-distance services, often
offer a "quiet car" where phone use is prohibited, much like the designated non-smoking
cars in the past. Mobile phone use on aircraft is also prohibited, because of
concerns of possible interference with aircraft radio communications. Most
schools in the U.S prohibit cell phones due to the high amount of class
disruptions due to their use, and due to the possibility of photographing
someone (without consent).
Camera phones and videophones that can capture video and take photographs are
increasingly being used by companies like Scoopt to cover breaking news. Stories
like the London Bombings, the Indian Ocean Tsunami and Hurricane Katrina have
been reported on by camera phone users on photo sharing sites like Flickr.
In Japan, cellular phone companies provide immediate notification of earthquakes
and other natural disasters to their customers free of charge. In the event of
an emergency, disaster response crews can locate trapped or injured people using
the signals from their mobile phones; an interactive menu accessible through the
phone's Internet browser notifies the company if the user is safe or in distress.
Technology
Mobile phones and the network they operate under vary
significantly from provider to provider, and even from nation to nation. However,
all of them communicate through electromagnetic radio waves with a cell site
base station, the antennas of which are usually mounted on a tower, pole, or
building.
The phones have a low-power transceiver that transmits voice and data to the
nearest cell sites, usually 5 to 8 miles (approximately 8 to 13 kilometres) away.
When the cellular phone or data device is turned on, it registers with the
mobile telephone exchange, or switch, with its unique identifiers, and will then
be alerted by the mobile switch when there is an incoming telephone call. The
handset constantly listens for the strongest signal being received from the
surrounding base stations. As the user moves around the network, the mobile
device will "handoff" to various cell sites during calls, or while waiting
(idle) between calls it will reselect cell sites.
Cell sites have relatively low-power (often only one or two watts) radio
transmitters which broadcast their presence and relay communications between the
mobile handsets and the switch. The switch in turn connects the call to another
subscriber of the same wireless service provider or to the public telephone
network, which includes the networks of other wireless carriers.
The dialogue between the handset and the cell site is a stream of digital data
that includes digitized audio (except for the first generation analog networks).
The technology that achieves this depends on the system which the mobile phone
operator has adopted. Some technologies include AMPS for analog, and D-AMPS,
CDMA2000, GSM, GPRS, EV-DO, and UMTS for digital communications. Each network
operator has a unique radio frequency band.
Mobile phone tower