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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). Fully automatic cellular networks were first introduced in the early to mid 1980s (the 1G generation). The first fully automatic cell phone system was the Nordic Mobile Telephone (NMT) system, introduced in 1981.

Prior mobile telephones (the so-called 0G generation), such as Mobile Telephone Service, date back to 1945. These were not categorized as cellular phones, since they did not support handover, i.e. automatic change of channel frequency in the middle of a call, when the user moved from one cell (base station coverage area) to another.

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, 3G, LG, Motorola, NEC, i-mate, Nokia, Panasonic (Matsushita Electric), Pantech Curitel, Philips, Sagem, Samsung, Sanyo, Sharp, Siemens SK Teletech, Sony Ericsson, T&A Alcatel, T-Mobile, 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. There are lots of different networks on mobile phones. Some are pay as you go, where you can buy top ups and add them to your phone, so there is no monthly bill, and some are pay monthly. This means you get a bill every month for how much calls and texts you make.

Martin 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.

Radiophones 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.

Luxembourg has the highest mobile phone penetration rate in the world, at 164% in December 2005. 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 .

Mobile 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, although the airline Emirates have announced plans to allow limited celluar phone usage on some flights. 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.

Mobile phone features

Invented in 1997, the camera phone is now 85% of the market. Mobile phones also often have features beyond sending text messages and making voice calls—including Internet browsing, music (MP3) playback, personal organizers, e-mail, built-in cameras and camcorders, ringtones, games, radio, Push-to-Talk (PTT), infrared and Bluetooth connectivity, call registers, ability to watch streaming video or download video for later viewing, and serving as a wireless modem for a PC.

In most countries, the person receiving a cellular phone call pays nothing. However, in China (including Hong Kong), Canada, and the United States, one can be charged per minute. In the United States, a few carriers are beginning to offer unlimited received phone calls. For example as of December 2006, Sprint now has 4 plans under "Sprint Free Incoming Plans" section of their website, although the restriction is the receiving phone must be on the Sprint PCS network.

Mobile phone forensics and evidence

The UK appears to be leading the world when in comes to mobile telephone forensics and evidence. Law enforcement globally, though, relies heavily upon mobile telephone evidence. The concerns over terrorism and the use by terrorist to use technology promoted an enquiry by the UK House of Commons Home Affairs Select Committee into the use of evidence from mobile telephone devices, prompting leading mobile telephone forensic specialists to identify forensic techniques available in this area.

Technology

Mobile phones and the network they operate under vary significantly from provider to provider, and 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.

Controversy

Health controversy

Concern has been raised regarding the possibility of an increase in certain types of rare tumors (cancer) in long-time, heavy users. More recently a pan-European study provided significant evidence of genetic damage under certain conditions. Some researchers also report the mobile phone industry has interfered with further research on health risks. So far, however, the World Health Organization Task Force on EMF effects on health has no definitive conclusion on the veracity of these allegations. (See also electromagnetic radiation hazard.) It is generally thought, however, that RF is incapable of producing any more than heating effects, as it is considered non-ionizing radiation; in other words, it lacks the energy to disrupt molecular bonds like those that occur in genetic mutations.

Driving controversy

Another controversial but potentially more lethal health concern is the correlation with road traffic accidents. Several studies have shown that motorists have a much higher risk of collisions and losing control of the vehicle while talking on the mobile telephone simultaneously with driving, even when using "hands-free" systems. Other studies have shown that using a mobile phone while driving poses the same risk as someone operating a vehicle while under the influence of alcohol. Four U.S. states and many countries, such as Australia, have now restricted or prohibited the use of mobile phones while driving. In Israel and nearly all European countries, driving whilst using a hand-held mobile phone is illegal.

Potential danger during electrical storms

In 2006, it was reported that mobile phone users suffer much more serious lesions than non-users, in case of being struck by lightning during an electrical storm. Cell phones do not, however, present the danger of a land line during an electrical storm; whereas wires can carry a lightning strike to a nearby telephone user, cell phone signals are immune to such danger.

Security concerns

Early mobile phones were limited in their security features. Some problems with these models were "cloning", a variant of identity theft, and "scanning" whereby third parties in the local area could intercept and eavesdrop in on calls. Analogue phones could also be listened to on some radio scanners.

Although more recent digital systems (such as GSM) have attempted to address these fundamental issues, security problems continue to persist. Vulnerabilities (such as SMS spoofing) have been found in many current protocols that continue to allow the possibility of eavesdropping or cloning .

It should be noted that on a technical level, CDMA is more secure than GSM and TDMA. This is due to the fact that all calls are separated onto their own channel and encoded with a unique encryption code.

Location tracking using mobile phones is also a concern.

As mobile phones begin to converge with the Internet, new security concerns will exist. Early forms of mobile viruses, spam, adult content and socially engineered scams have begun to target Internet capable mobile phones. Users of mobile phones will be much less tolerant of such malicious activities.

Recently, it has been shown that cell phone microphones can be remotely activated for use as "roving bugs". This has been approved as legal in the U.S. under existing wiretapping laws. This capability is confirmed by the Western Region Security Office of the U.S. Department of Commerce (citing a newsletter from the National Reconnaissance Office), which says that :

A cellular telephone can be turned into a microphone and transmitter for the purpose of listening to conversations in the vicinity of the phone. This is done by transmitting to the cell phone a maintenance command on the control channel. This command places the cellular telephone in the "diagnostic mode." When this is done, conversations in the immediate area of the telephone can be monitored over the voice channel.

Claims of Danger at Gas Pumps

Since 1999 there have been many claims that cell phones can cause electrostatic discharge that ignite fumes in the air due to the battery, signal, or ringer. These have been proven to be false as the battery is the same kind as a car battery, the signals are too weak to ever start it, and cell phones don't actually have a ringer. Despite this many places have banned cell phone use near gas pumps including places in Canada and Belgium.

It has been alleged that the bans are maintained in order to ensure patrons are not distracted while refuelling, which could cause potentially hazardous spills.

There is a mythbusters episode where they test whether a cell phone is dangerous at the pump. It proved not to be dangerous.

Claims of danger on aircraft

Almost all countries and airlines ban the use of mobile phones on their aircraft due to unproven claims that they can interfere with systems like the radio link to Air Traffic Control and the autopilot. When Crossair Flight LX498 crashed early in 2000, many countries that had previously been reluctant to introduce this legislation adopted it because of claims it was downed by passenger cell phone use, but the official report blames pilot error and makes no mention of mobile phone use.

Mobile communication studies

Since 2002 there has been an enormous increase in academic research regarding the social impact of mobile phones. Books include:

• Agar, Jon, Constant Touch: A Global History of the Mobile Phone, 2004
• Glotz, Peter & Bertsch, Stefan, eds. Thumb Culture: The Meaning of Mobile Phones for Society, 2005
• Katz, James E. & Aakhus, Mark, eds. Perpetual Contact: Mobile Communication, Private Talk, Public Performance, 2002
• Kavoori, Anandam & Arceneaux, Noah, eds. The Cell Phone Reader: Essays in Social Transformation, 2006
• Nyíri, Kristóf, ed. Mobile Communication: Essays on Cognition and Community, 2003
• Nyíri, Kristóf, ed. Mobile Learning: Essays on Philosophy, Psychology and Education, 2003
• Nyíri, Kristóf, ed. Mobile Democracy: Essays on Society, Self and Politics, 2003
• Nyíri, Kristóf, ed. A Sense of Place: The Global and the Local in Mobile Communication, 2005
• Nyíri, Kristóf, ed. Mobile Understanding: The Epistemology of Ubiquitous Communication, 2006
• Levinson, Paul, Cellphone: The Story of the World's Most Mobile Medium, and How It Has Transformed Everything! 2004
• Rheingold, Howard, Smart Mobs: The Next Social Revolution, 2002

Terminology

Related non-cell-phone systems

Cordless phone (portable phone)

Cordless phones are standard telephones with radio handsets. Unlike mobile phones, cordless phones use private base stations that are not shared between subscribers. The base station is connected to a land-line. Increasingly, with wireless local loop technologies, namely DECT, the distinction is blurred.

Professional Mobile Radio

Advanced professional mobile radio systems can be very similar to cell phone systems. Notably, the IDEN standard has been used as both a private trunked radio system as well as the technology for several large public providers. Similar attempts have even been made to use TETRA, the European digital PMR standard, to implement public mobile networks.

Radio phone

This is a term which covers radios which could connect into the telephone network. These phones may not be mobile; for example, they may require a mains power supply. Also, they may require the assistance of a human operator to set up a PSTN phone call.

Terms in other countries

See also

Sources

1. "Total mobile subscribers top 1.8 billion".
2. Up to 90 percent of globe to have mobile coverage
3. "Mobile growth fastest in Africa".
4. "Phone revolution makes Africa upwardly mobile".
5. Long-term mobile phone use raises brain tumor risk: study, Reuters, 31 March 2006
6. http://www.isaac.cs.berkeley.edu/isaac/gsm-faq.html

External links

• Mobile phones at the Open Directory Project
• Explaining Cell Phone Reception - Mobiledia
• The British Library - finding information on the mobile phone industry

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• Consumer electronics
• Embedded systems
• Mobile phones
• Mobile telephony
• Telecommunications equipment