Technology, Cellular

BIBLIOGRAPHY

Japan developed the world’s first analog mobile phones in 1979. They spread rapidly, outstripping the world’s landline systems within fifteen years. By 2006 the majority of the citizens of Europe, North America, and the wealthier nations of Asia, Africa, the Caribbean, and Latin America owned mobile phones. The United Kingdom had more mobiles than people, and there were 207 million users in the United States. More than twenty manufacturers produced them, and most nations had converged on GSM transmission, which was designed for European compatibility, although it coexisted with CMDA and iDen standards in the United States, Australia, Japan, and South Korea.

Most innovations have come from Japan, where a dense population that commutes to work, a high-tech industry long focused on miniaturization, and conducive social and consumer relationships led to early adoptions of camera and video phones, GPS (global positioning systems), text messaging, Internet, and music player capabilities. In Japan third-generation (3G) systems were the norm by 2005. Europe, South Korea, Taiwan, and coastal China are said to lag behind Japan by eighteen months, and North America lags three years behind. Elsewhere, developing nations rejected landlines in favor of cheaper mobile systems. The rollout of 4G systems is anticipated in Japan around 2010.

Mobile phones are not without problems. Many studies confirm the higher risk of auto accidents while using mobiles, even hands-free systems. Some scientific evidence shows increases in cancerous tumors among heavy, long-time users. Transmission towers are unwelcome sights in residential areas. Mobiles are also used in identity theft and credit card crime, in the coordination of terrorist attacks, and as detonators for bombs. Due to possible radio-wave interference, their use is banned in airplanes, hospitals, and some high-tech facilities. Theft of mobiles is common, with black markets on the Internet and in major cities.

Despite their problems, mobile phones have changed human communication profoundly, freeing it from the ancient constraints of physical proximity and spatial immobility. They have been rapidly adopted across cultures, age groups, and literacy and income levels, though in polyvalent modes. Mobile use initially was similar to the use of pagers by doctors and business people. Later mobiles became status items, especially among teenagers, who engaged in a “personalization culture” that included the use of faceplates, hand cords, stickers, and ringtones. For adults, status shifted to broadband Internet access.

Mobiles have become a basic technology of emergency response. Drivers use them to report accidents, police and fire departments use them as a back channel in disasters, and the elderly carry them “just in case.” Australian studies show that high percentages of mobile users are “cellular Samaritans” who use their phones to summon help for those in difficulty. Camera and video phones allowed instant reporting on the 2005 Indian Ocean tsunami and Hurricane Katrina. Japanese users can even be informed of impending earthquakes.

Sociologists have noted across cultures, genders, and age groups an increase in “grooming calls,” by which members of a family or group show concern and “nearness.” These short, frequent calls reinforce bonds of affection. Immigrant families and diasporic clans in particular do this. However, the “universal availability” of mobile users also allows the reinforcement of hierarchy. Bosses call employees outside work hours, parents monitor children, and couples monitor each other: “If you are without a mobile phone it means that no one depends on you for urgent direction” (Bautsch et al. 2001, p. 3).

The location of mobile use is problematic. Mobiles have been banned from theaters, religious institutions, funerals, airplanes, and many restaurants, and their use is frowned upon in museums, bookstores, trains, and buses. A dynamic of “civil inattention” has arisen in which bystanders pretend to ignore mobile conversations and speakers use vague or euphemistic language. Mobiles are also used as symbolic bodyguards in public areas to ward off unwanted attention or to refuse to participate in public space: “Public space is no longer lived in all of its aspects, stimuli and prospects, but is kept in the background of an itinerant cellular intimacy” (Fortunati 2000, p. 11).

Receiving mobile calls is an area without norms. Phones may be on, off, or in message-only mode, as users determine their degree of availability. Users decide whom to give their numbers to, whom to block, whom to answer immediately, and who hears a busy signal. Finnish studies show that men are more likely than women to turn mobiles off to avoid social control. Because calls arrive unpredictably but habit dictates that they be answered, face-to-face conversations and other calls must be “suspended.” Such interruptions cause anxiety for both parties, leading to anomie and difficult restarts. Users must also manage facial expressions and body language for multiple audiences, indicating primary and secondary importance to those present and absent. Such “managed availability,” however, has increased the capacity of parents in particular to coordinate various roles. But managing role conflicts and the discrepant awareness of conversation partners may be difficult for older users, and may promote broad but shallow relationships among younger users.

One alternative is SMS (short message systems), or “text messaging.” SMS patterns tend to follow earlier pager use, though today’s users can communicate through emoticons or delay responses via timers. Finnish studies, however, show that feedback is expected within 15–30 minutes. In Asia SMS users tend to be young and to belong to linguistic subcultures, and they are often killing time in public places or transport. SMS offers friendship tryouts, invitations without risk, and the cost is shared by sender and receiver. Some Japanese teens maintain multiple personae for hundreds of meru tomo (email friends), and SMS is the common channel for arranging enjo kosai, or paid “dates,” between businessmen and high school girls.

The mobile’s impact on individuality is also an area of concern. Traditional feelings of longing, homesickness, sadness, or insecurity are assuaged by calls and thus leveled out. Mobiles diminish the number of true hellos and goodbyes. Lost are reflective periods when people review past actions and plan future ones. This culture of “nomadic intimacy” may portend more peripheral relationships, but fewer deep ones (Fortunati 2000). The deregulation of social life is another implication. “Nights out [are] characterized by endless deferrals and reshuffling of meetings and events which might never occur,” writes Sadie Plant (2003, p. 64), and “freedom from punctuality is permitted by constant ability to update other parties as to your status” (Townsend 2000, p. 94). In Italy the popularity of the mobile “seems to be associated with its support for a spontaneous, disorganized lifestyle that has always reigned among most of the country’s population” (Geser 2004).

The mobile has also made covert information exchange more possible. Some critics call this gossip, but others see it as decentralizing or democratizing. Parents communicate with other parents about children’s attitudes and whereabouts; employees engage in a similar dynamic about bosses; and law officers speak to each other rather than through dispatchers or superiors. In China mobile networks have spread news censored by the government and allowed seemingly spontaneous demonstrations. But studies show that mothers and wives act as the mobile information hubs of most families, so although mobiles may reduce the number of shared family experiences, they seem to be assimilated to traditional roles.

In the future, as the distribution of antennas grows denser, the location of every mobile will be determinable by GPS. In Japan, location within 30 feet was the norm by 2006, whereas in the United States the few GPS-enabled systems were accurate to 300 feet. GPS will be standard in 4G systems and, combined with built-in compasses, will allow users to point phones at buildings to find addresses, businesses, and friends, as well as to navigate roads. One side effect may be a barrage of business advertising. Barcode scanners may also become standard on mobiles, so that consumers concerned about food safety and product origin can “source” their purchases on databases before buying. Pocket-sized mobiles with SIMs (subscriber identity modules) will serve as credit cards that can be passed over sensors, like RFID (radio frequency interface devices) tags (Kohiyama 2005). Because SIMs are removable, users may have different mobiles for different occasions; they may even use friends’ phones, because their SIM carries their rate plans and caller lists. Batteries may become universally available, recharged, or swapped cheaply at kiosks or vending machines. Increased demand for Internet uses will lead to multilayered rate plans, and SMS will prevail underground on trains and in subsurface rooms. South Korea has announced plans to send out traffic tickets, fines, and even indictments by SMS. All mobiles will connect to nearby workplace, school, or community LANs to make use of the Internet when possible. Future architectural designs will change, allowing for ubiquitous mobile phone niches. World cities such as Tokyo, New York, London, and Paris may consist of people whose work requires face-to-face proximity for deals and transactions, whereas mobiles will allow others to work nomadically.

SEE ALSO Technology, Video

BIBLIOGRAPHY

Bautsch, Holly, Julien Ganger, Timothy Karnjate, et al. 2001. An Investigation of Mobile Phone Use: A Socio-technical Approach. Unpublished research report, Department of Industrial Engineering, University of Wisconsin-Madison. http://www.mobilesociety.net/uploadi/editor/IE449_0108.pdf.

Brown, Barry, Nicola Green, and Richard Harper, eds. 2002. Wireless World: Social and Interactional Aspects of the Mobile Age. London: Springer-Verlag.

Dziesinski, Michael J. 2003. What Is “Keitai Culture”?: Investigations into the Social Impact of Mobile Telephony with Society in Contemporary Japan. http://towakudai.blogs.com/Keitai.Research.Survey.pdf.

Fortunati, Leopoldina. 2000. The Mobile Phone: New Social Categories and Relations. Trieste, Italy: University of Trieste.

Geser, Hans. 2004. Towards a Sociological Theory of the Mobile Phone. http://socio.ch/mobile/t_geser1.htm.

Goffman, Erving. 1963. Behavior in Public Places: Notes on the Social Organization of Gatherings. New York: Free Press.

Ito, Mizoko, Daisuke Okabe, and Misa Matsuda, eds. 2006. Personal, Portable, Pedestrian: Mobile Phones in Japanese Life. Boston: MIT Press.

Katz, James E., and Mark A. Aakhus 2002. Perpetual Contact: Mobile Communication, Private Talk, Public Performance. Cambridge, U.K.: Cambridge University Press.

Kohiyama, Kenji. 2005. The Future of the Ketai. Japan Media Review, August 11. http://www.japanmediareview.com/japan/stories/050811kohiyama/.

Lasen, Amparo. 2005. The Social Shaping of Fixed and Mobile Networks: A Historical Comparison. Surrey, U.K.: University of Surrey.

Markoff, John, and Martin Fackler. 2006. With a Cellphone as My Guide. New York Times, June 28.

Plant, Sadie. 2003. On the Mobile: The Effects of Mobile Telephones on Social and Individual Life. http://www.motorola.com/mot/doc/0/234_MotDoc.pdf.

Sloane, Andy, and Felix van Rijn, eds. 2000. Home Informatics and Telematics: Information, Technology, and Society. Boston: Kluwer.

Townsend, Anthony M. 2000. Life in the Real-Time City: Mobile Telephones and Urban Metabolism. Journal of Urban Technology 7 (2): 85–104.

Tsai, Michelle. 2006. What’s a Phone For? Wall Street Journal (Eastern edition), June 19: R 12.

Wellman, Barry. 2001. Physical Place and Cyber Place: The Rise of Personalized Networking. International Journal of Urban and Regional Research 25 (2): 227–252.

Wellman, Barry, Janet Salaff, Dimitrina Dimitrova, et al. 1996. Computer Networks as Social Networks: Collaborative Work, Telework, and Virtual Community. Annual Review of Sociology 22: 213–238.

William Marling

Cellular telephone

Resources

Cellular telephone (cell phone) technology is also called cellular radio. American inventor Marty Cooper is considered the inventor of the cellular phone. While working for Motorola Corporation, Cooper developed the concept of using wireless communications with a portable device to make telephone calls. He made the first cell phone call in New York City on April 3, 1973, with a brick-sized, 30-ounce (850-gram) device. The call was placed between competitors Motorola and AT&T Bell Laboratories.

The cellular radio network became fully operational in North America in 1978. This technology relies on the distribution of what are called cell sites over a wide geographical area. Each cell site consists of a radio transceiver and a controller that sends and receives signals from mobile phones in the area to a telephone switch. The signals can be beamed to a central point called the mobile telecommunications switching office. This office places calls from land-based telephones to mobile telephones, and allows mobile phones to operate across the globe as the phone signal is relayed from one switching office to another.

Mobile telephone service was severely limited in availability until 1984. Until that year, only urban areas had mobile service, primarily for city services. Each city had a single antenna to transmit signals to and from the antennae of car phones. The Federal Communications Commission (FCC) assigned only 12 to 24 frequencies to an urban area. As a result, only one or two-dozen car phone calls could take place in the entire city at one time. The system was frustrating. Users had to wait up to 30 minutes to get a dial tone, and potential mobile phone customers were put on five to ten-year waiting lists.

Cellular phone technology changed all this. In a cellular system, each metropolitan area is divided into broadcasting zones, or cells. Each 6- to 10-mi² (15.5- to 25.9-km²) cell has its own broadcast antenna or tower. As a car phone moves through the city, a computer automatically passes its frequency from one cell to the next. A single frequency can be used for multiple, nonadjacent cells; and, as the number of users increases, cells can be subdivided into any number of smaller cells, so the cellular system is capable of far greater usage than the old mobile service.

Rudimentary cellular technology was known as early as 1947. By the 1960s and 1970s, mobile phone service was overcrowded, and the need for a more efficient system led to a re-examination and refinement of cellular technology. Bell Laboratories, a research division within the American Telephone and Telegraph Company (AT&T), took the lead in this development. A prototype network had been developed by 1971. In 1978, the first experimental cellular service, which was called the Advanced Mobile Phone Service (AMPS), was operational in the Chicago, Illinois, area. AT&T was declared a monopoly and was reorganized in 1978. This reorganization opened the cellular phone market to competitors. Seven new regional phone companies began to pursue the cellular phone market.

In 1981, the FCC issued cellular phone regulations. In October 1983, Ameritech Mobile Communications (a subsidiary resulting from the Bell breakup) introduced the first American commercial cellular system in Chicago. Cellular service was also available by then in a number of other countries. The FCC also allowed one non-Bell service in each metropolitan area. For example, Cellular One began transmitting in Washington, DC, in December 1983.

As the number of cellular phone systems and subscribers increased, the costs for equipment and service decreased. As of 2006, pocket-size personal telephones based on cellular technology were available, as were machines that combine a cellular phone, facsimile machine, voice and e-mail systems, answering machine, pager, video phone, camera, Internet-browsing, music (MP3), personal organizers, ring tones, games, instant messaging, and a number of other features.

The cellular technology that relied on ground-based antennae is giving way to satellite technology. Communication satellites are being used increasingly by the cellular services to provide uniform service as the telephone and its user travel through a number of cells. A new form of satellite technology called Global Mobile Personal Communications by Satellite (GMPCS) allows telecommunication virtually anywhere in the world.

Earlier communication satellites traveled high above the Earth and orbited at the same speed as Earth rotates. The satellites stayed in one position relative to the ground. This geosynchronous orbit caused delays and loss of quality in signal transmission. Now, GMPCS satellites have much lower orbits and can be used in clusters called constellations to transfer signals rapidly and with greater clarity. Developing countries and remote areas have access to cellular service, and, during natural disasters, emergency relief can be mobilized and coordinated when land-line telephones have been disabled or the region is remote.

The telephone industry is making advances toward a single telephone number per person. This is called a Personal Communications Network or PCN. The PCN can be used for both land-line networks (telephone service by cable that has traditionally been provided to homes and businesses) and cellular systems. Basically, the service is a form of call-forwarding in which the signal is transferred through the land-line network until a transceiver detects that the cell phone is within range. The call is then sent as a cellular signal.

Further development is expected to lead to digital transmissions that convert conversations into computer code that can be transferred by advanced cellular technology. In addition, microcellular technology that uses smaller and more closely spaced transceivers instead of cellular towers or by satellite is on the horizon. Microcells will relieve the pressure to provide enough access telephone numbers, and the FCC is working on modifying communications regulations to suit the new technologies and to free frequencies with less demand for cellular use. Radio frequencies may be converted to phone service, and dedicated land-lines for telephone service may be outmoded by delivering phone signals via cable television.

In 2005, the number of cell phones in the world was estimated to be 2.14 billion. Hong Kong has the highest percentage of people with cell phones: nearly 129% (more than one per person). As of 2006, about 80% of the world’s population has access to cell phone coverage. This percentage is expected to increase to 90% by 2010. Telecommunications experts predict

KEY TERMS

Cellular signal— An analog or digital telephone signal that is transmitted on a specific frequency among areas or cells from cellular towers or by satellite.

Land-line network— A communications network that uses underground or overhead cables to carry signals.

Microcellular technology— Method of transmitting cellular telephone signals among smaller areas or microcells by transceivers or satellites.

Personal Communications Network— Also called a Personal Communications Service (PCS), a technology that uses one telephone access number assigned per person to transmit both land-line and cellular telephone calls.

that eventually all telephones will be wireless. Some of the largest cell phone manufacturers include Audiovox, Fujitsu, Kyocera, Motorola, NEC, Nokia, Panasonic, Philips, Samsung, Sanyo, Sharp, Sony, and Toshiba.

The ease of use and life-saving potential of cellular telephones has not come without negative aspects. Foremost is the use of cellular telephones in motor vehicles. The use of a phone can divert the driver’s attention from the road. An increase in motor vehicle accidents and in injuries and death has been attributed to the use of cellular telephones. Increasingly, legislation is requiring the use of hands-off cellular technology in motor vehicles, where the phone is positioned somewhere on the dashboard and a speaker is activated to carry on the conversation. In some states, such as New York, cell phone use is prohibited while driving.

See also Fiber optics; Synthesizer, voice.

Resources

BOOKS

Lindholm, Christian, Turkka Keinonen, and Harri Kiljander. Mobile Usability, How Nokia Changed the Face of the Mobile Phone. New York: McGraw-Hill, 2003.

Dodd, A.Z. The Essential Guide to Telecommunications, 3rd ed. Englewood Cliffs, NJ: Prentice-Hall, 2001.

Walters, Stephen M. The New Telephony. Upper Saddle River, NJ: Prentice Hall PTR, 2002.

Brian Hoyle

Cellular Technology

The cellular phone is the latest in a long line of mobile, portable, and wireless technologies extending back to the 1930s. Military forces were among the first to use mobile radio communications. Early mobile radio equipment for the military involved large transmitters aboard military vehicles with huge antennas and high transmitter power. The large, robust military vehicles were capable of accommodating the massive, power-hungry equipment.

The first use of radio communications for civilian land vehicles was primarily by police departments. The earliest systems were one-way, where the dispatcher could broadcast to all cars the location and nature of a problem. There was no return communication and thus no verification of a response to the problem, but it was better than nothing.

The first successful installation of a large two-way police radio system was for the Connecticut State Police in 1939. This system used a newly invented type of radio called frequency modulation (FM). This system set the standard for mobile radio for many years.

Two-way radio installed in automobiles inspired the idea for a mobile telephone service. The first police radio was a simple , or one-way, system, meaning that the mobile unit could only receive communications. The two-way police radio was a half duplex system in which both the mobile and base units could transmit and receive but not at the same time. Proper radio procedures were required, such as saying "over" to invite the other station to transmit, and using radio call signs. The frequency was shared by a number of users and conversations were far from private.

Ideally, a mobile telephone is a full duplex system where both stations transmit and receive simultaneously and the channel is not shared. The first full duplex mobile telephone systems were installed in large cities in the 1950s. The systems used base stations connected to the public switched telephone network (PSTN) and had a range of 60 to 80 kilometers (37 to 50 miles). Mobile telephones had a telephone number, rang like a normal telephone, and were full duplex. Because of the large area covered by the base station and the limited number of available channels or radio frequencies, the mobile phone system (MPS) quickly reached full capacity. Priority for new subscribers was given to physicians and others needing emergency communications, and the waiting lists were very long.

A Texas rancher, Tom Carter, played an important role in mobile telephone history. Carter had made a simple device that would allow his private business two-way radio system to be used with his office telephone when he was out on the ranch. The telephone company refused to allow Carter to connect his device to the PSTN and Carter took the case to court. Although it took fifteen years, the Federal Communications Commission (FCC) in 1968 ruled in favor of Carter in the landmark Carterfone decision. The action opened the PSTN to radio connections as well as those for computer data and other devices.

In the 1970s Bell Telephone Laboratories began investigating a replacement system for the MPS. After the Carterfone decision, competitors were gearing up to use new technologies to provide alternative mobile telephone service. The FCC reassigned a number of under-used ultra-high frequency (UHF) television channels for a new, advanced mobile phone system (AMPS). The AMPS had considerably more channels than the older MPS and had two sets—one for the local telephone company, and a second set for a competitor.

The concept of the AMPS was to increase the reuse of the communications channels. Frequency reuse occurs when two stations occupy the same frequency or channel but are separated by such a distance that they do not interfere. The MPS used high antennas to provide a 60 to 80 kilometer (37 to 50 mile) range, but no two base stations could be closer than about 150 kilometers (93 miles) to avoid interference. In the AMPS, the height of the base station antenna and the transmitter power are limited so the range of a cell is only about 11 to 15 kilometers (7 to 9 miles). In addition, the base station controls the transmitter powers of the mobile units. This ensures that the least amount of power is used, which limits the interference and allows the channels to be reused by another cell only 20 to 30 kilometers (12 to 19 miles) away.

The cells are interconnected with wire lines or microwave radio links. When a user leaves the coverage of one cell and enters another, the new cell provides continuing communications, a process called handoff. The cell system must determine which cell is most capable of picking up the user, acquire that user, and connect the user to the correct land line. All of this is invisible to the user.

The handoff process involves a number of algorithms using various data from the mobile telephone. First, every cell phone handset has a digital address that is continuously transmitted. Any cell site, or base station, can positively identify signals being received even though many of the received signals are not communicating with that cell site. Cell sites continually communicate with neighboring cell sites and compare the signal quality of the mobile units being received. If a particular mobile telephone unit has a superior signal in a neighboring cell site, the handoff process begins. This has to be done with care, as certain situations can cause a signal to fade temporarily in one site while improving at another, perhaps only for a few seconds. If a handoff is initiated prematurely, it will be necessary to restore the mobile phone to the original cell site quickly.

In addition to determining which cell site is capable of providing the best communications to the mobile phone, the computer system must also switch the land lines and keep a tally of the airtime for billing purposes.

Early cell telephone systems only allowed customers to use the system to which the user was a subscriber. Later, roaming, or using another company's cell system, was initiated. This came with very high prices and complicated billing procedures. As the cellular mobile phone system became financially successful, more cell sites were constructed, and now most of the continental United States has cell coverage. Proposed regulations would require the cell system to determine the location of a handset in emergency situations. Agreements between cellular telephone companies simplified roaming, and a customer can now travel through much of the country with no loss of service. This is called a seamless system.

AMPS uses frequency modulation (FM), which is the same technology used in the very first mobile two-way radio in 1939. FM has performed well for many years but is inferior to many digital systems. These digital systems opened up the way for more sophisticated applications—especially non-voice communications such as paging, e-mail, and Internet services. Many mobile telephones became not just telephones but personal communications systems or PCSs.

It is important for a global, seamless, wireless cell phone system to have well thought-out standards to which the cell sites adhere. With the advent of the more sophisticated digital cell systems, a large number of new standards have appeared. These include a European standard, global system for mobile (GSM), code division multiple access (CDMA), time division multiple access (TDMA), and others. The complexity of modern handsets has increased because of the need to operate with a number of different standards. The modern cellular telephone is a sophisticated, cost-effective, and worldwide communications device and promises to become more capable in the future.

see also Cell Phones; Networks; Telecommunications; Wireless Technology.

Albert D. Helfrick

Bibliography

Kellogg, Steven, ed. The Comprehensive Guide to Wireless Technology. Fuquay-Varina, NC: APDG Publishing, 2000.

Stetz, Penelope. The Cell Phone Handbook: Everything You Wanted to Know About Wireless Telephony (But Didn't Know Who or What to Ask). Newport, RI: Aegis Publishing Group, 1999.

Cellular telephone

Cellular telephone technology is also called cellular radio . The cellular radio network became fully operational in North America in 1978. This technology relies on the distribution of what are called cell sites over a wide geographical area. Each cell site consists of a radio transceiver and a controller that sends and receives signals from the mobile phones in the area to a telephone switch. The signals can be beamed to a central point called the mobile telecommunications switching office. This office places calls from land based telephones to mobile telephones, and allows mobile phones to operate across the globe as the phone signal is relayed from one switching office to another.

Mobile telephone service was severely limited in availability until 1984. Until that year, only urban areas had mobile service, primarily for city services. Each city had a single antenna to transmit signals to and from the antennae of car phones. The Federal Communications Commission (FCC) assigned only 12–4 frequencies to an urban area. As a result, only one or two-dozen car phone calls could take place in the entire city at one time. The system was frustrating. Users had to wait up to 30 minutes to get a dial tone, and potential mobile phone customers were put on five to 10-year waiting lists.

Cellular phone technology changed all this. In a cellular system, each metropolitan area is divided into broadcasting zones or "cells." Each 6–10-mi2 (15.5–25.9-km2) cell has its own broadcast antenna or tower. As a car phone moves through the city, a computer automatically passes its frequency from one cell to the next. A single frequency can be used for multiple, nonadjacent cells; and, as the number of users increases, cells can be subdivided into any number of smaller cells, so the cellular system is capable of far greater usage than the old mobile service.

Rudimentary cellular technology was known as early as 1947. By the 1960s and 1970s, mobile phone service was overcrowded, and the need for a more efficient system led to a re-examination and refinement of cellular technology. Bell Laboratories, a research division within the American Telephone and Telegraph Company (AT&T), took the lead in this development. A prototype network had been developed by 1971. In 1978 the first experimental cellular service, which was called the Advanced Mobile Phone Service (AMPS), was operational in the Chicago, Illinois, area. AT&T was declared a monopoly and was reorganized in 1978. This opened the cellular phone market to competitors. Seven new regional phone companies began to pursue the cellular phone market.

In 1981, the FCC issued cellular phone regulations. In October 1983, Ameritech Mobile Communications (a subsidiary resulting from the Bell breakup) introduced the first American commercial cellular system in Chicago. Cellular service was also available by then in a number of other countries. The FCC also allowed one non-Bell service in each metropolitan area. For example, Cellular One began transmitting in Washington, D.C., in December 1983.

As the number of cellular phone systems and subscribers increased, the costs for equipment and service decreased. As of 2002, pocket-size personal telephones based on cellular technology are available, as are machines that combine a cellular phone, facsimile machine, voice and e-mail systems, answering machine, and pager.

The cellular technology that relied on ground-based antennae is giving way to satellite technology. Communication satellites are being used increasingly by the cellular services to provide uniform service as the telephone and its user travel through a number of cells. A new form of satellite technology called Global Mobile Personal Communications by Satellite (GMPCS) allows telecommunication virtually anywhere in the world.

Earlier communication satellites traveled high above Earth and orbited at the same speed as Earth rotates. The satellites stayed in one position relative to the ground. This geosynchronous orbit caused delays and loss of quality in signal transmission. GMPCS satellites have much lower orbits and can be used in clusters called constellations to transfer signals rapidly and with greater clarity. Developing countries and remote areas have access to cellular service, and, during natural disasters, emergency relief can be mobilized and coordinated when land-line telephones have been disabled or the region is remote.

The telephone industry is making advances toward a single telephone number per person. This is called a Personal Communications Network or PCN. The PCN can be used for both land-line networks (telephone service by cable that has traditionally been provided to homes and businesses) and cellular systems. Basically, this service is a form of call-forwarding in which the signal is transferred through the land-line network until a transceiver detects that the cell phone is within range. The call is then sent as a cellular signal.

Further development is expected to lead to digital transmissions that convert conversations into computer code that can be transferred by advanced cellular technology. Also microcellular technology that uses smaller and more closely spaced transceivers instead of cellular towers or by satellite is on the horizon. Microcells will relieve the pressure to provide enough access telephone numbers, and the FCC is working on modifying communications regulations to suit the new technologies and to free frequencies with less demand for cellular use. Radio frequencies may be converted to phone service, and dedicated land-lines for telephone service may be outmoded by delivering phone signals via cable television .

Telecommunications experts predict that all telephones will be wireless by 2010.

The ease of use and life saving potential of cellular telephones has not come without negative aspects. Foremost is the use of cellular telephones in motor vehicles.

The use of a phone can divert the driver's attention from the road. The increase in motor vehicle accidents and in injuries and death has been attributed to the use of cellular telephones. Increasingly, legislation is requiring the use of "hands off" cellular technology in motor vehicles, where the phone is positioned somewhere on the dashboard and a speaker is activated to carry on the conversation.

See also Fiber optics; Synthesizer, voice.

Resources

books

Dodd, A.Z. The Essential Guide to Telecommunications. 3rd ed. Englewood Cliffs, NJ: Prentice-Hall, 2001.

Laino, J. The Telephony Book-Understanding Systems and Services. Gilroy, CA: CMP Books, 1999.

Noll, A.M. Introduction to Telephones and Telephone Systems Norwood. MA: Artech House, 1999.

Brian Hoyle

KEY TERMS

Cellular signal

—An analog or digital telephone signal that is transmitted on a specific frequency among areas or cells from cellular towers or by satellite.

Land-line network

—A communications network that uses underground or overhead cables to carry signals.

Microcellular technology

—Method of transmitting cellular telephone signals among smaller areas or microcells by transceivers or satellites.

Personal Communications Network

—Also called a Personal Communications Service (PCS), a technology that uses one telephone access number assigned per person to transmit both land-line and cellular telephone calls.

cel·lu·lar / ˈselyələr/ • adj. 1. of, relating to, or consisting of living cells: cellular proliferation.2. denoting or relating to a mobile telephone system that uses a number of short-range radio stations to cover the area that it serves, the signal being automatically switched from one station to another as the user travels about.3. consisting of small compartments or rooms: cellular accommodations.DERIVATIVES: cel·lu·lar·i·ty / ˌselyəˈlaritē/ n.