A mobile phone (or cellphone[a]) is a portable telephone that can make and receive calls over a radio frequency link while the user is moving within a telephone service area, as opposed to a fixed-location phone (landline phone). The radio frequency link establishes a connection to the switching systems of a mobile phone operator, which provides access to the public switched telephone network (PSTN). Modern mobile telephone services use a cellular network architecture, and therefore mobile telephones are called cellphones (or "cell phones") in North America. In addition to telephony, digital mobile phones support a variety of other services, such as text messaging, multimedia messaging, email, Internet access (via LTE, 5G NR or Wi-Fi), short-range wireless communications (infrared, Bluetooth), satellite access (navigation, messaging connectivity), business applications, payments (via NFC), multimedia playback and streaming (radio, television), digital photography, and video games. Mobile phones offering only basic capabilities are known as feature phones (slang: "dumbphones"); mobile phones that offer greatly advanced computing capabilities are referred to as smartphones.[1]
The first handheld mobile phone was demonstrated by Martin Cooper of Motorola in New York City on 3 April 1973, using a handset weighing c. 2 kilograms (4.4 lbs).[2] In 1979, Nippon Telegraph and Telephone (NTT) launched the world's first cellular network in Japan.[3] In 1983, the DynaTAC 8000x was the first commercially available handheld mobile phone. From 1983 to 2014, worldwide mobile phone subscriptions grew to over seven billion; enough to provide one for every person on Earth.[4] In the first quarter of 2016, the top smartphone developers worldwide were Samsung, Apple and Huawei; smartphone sales represented 78 percent of total mobile phone sales.[5] For feature phones as of 2016[update], the top-selling brands were Samsung, Nokia and Alcatel.[6]
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Mobile phones are considered an important human invention as they have been one of the most widely used and sold pieces of consumer technology.[7] The growth in popularity has been rapid in some places, for example, in the UK, the total number of mobile phones overtook the number of houses in 1999.[8] Today, mobile phones are globally ubiquitous,[9] and in almost half the world's countries, over 90% of the population owns at least one.[10]
A handheld mobile radio telephone service was envisioned in the early stages of radio engineering. In 1917, Finnish inventor Eric Tigerstedt filed a patent for a "pocket-size folding telephone with a very thin carbon microphone". Early predecessors of cellular phones included analog radio communications from ships and trains. The race to create truly portable telephone devices began after World War II, with developments taking place in many countries. The advances in mobile telephony have been traced in successive "generations", starting with the early zeroth-generation (0G) services, such as Bell System's Mobile Telephone Service and its successor, the Improved Mobile Telephone Service. These 0G systems were not cellular, supported a few simultaneous calls, and were very expensive.
The first handheld cellular mobile phone was demonstrated by John F. Mitchell[11][12] and Martin Cooper of Motorola in 1973, using a handset weighing 2 kilograms (4.4 lb).[2] The first commercial automated cellular network (1G) analog was launched in Japan by Nippon Telegraph and Telephone in 1979. This was followed in 1981 by the simultaneous launch of the Nordic Mobile Telephone (NMT) system in Denmark, Finland, Norway, and Sweden.[13] Several other countries then followed in the early to mid-1980s. These first-generation (1G) systems could support far more simultaneous calls but still used analog cellular technology. In 1983, the DynaTAC 8000x was the first commercially available handheld mobile phone.
In 1991, the second-generation (2G) digital cellular technology was launched in Finland by Radiolinja on the GSM standard. This sparked competition in the sector as the new operators challenged the incumbent 1G network operators. The GSM standard is a European initiative expressed at the CEPT ("Confrence Europenne des Postes et Telecommunications", European Postal and Telecommunications conference). The Franco-German R&D cooperation demonstrated the technical feasibility, and in 1987, a Memorandum of Understanding was signed between 13 European countries that agreed to launch a commercial service by 1991. The first version of the GSM standard had 6,000 pages. The IEEE and RSE awarded Thomas Haug and Philippe Dupuis the 2018 James Clerk Maxwell medal for their contributions to the first digital mobile telephone standard.[14] In 2018, the GSM was used by over 5 billion people in over 220 countries. The GSM (2G) has evolved into 3G, 4G and 5G. The standardization body for GSM started at the CEPT Working Group GSM (Group Special Mobile) in 1982 under the umbrella of CEPT. In 1988, ETSI was established, and all CEPT standardization activities were transferred to ETSI. Working Group GSM became Technical Committee GSM. In 1991, it became Technical Committee SMG (Special Mobile Group) when ETSI tasked the committee with UMTS (3G). In addition to transmitting voice over digital signals, the 2G network introduced data services for mobile, starting with SMS text messages, then expanding to Multimedia Messaging Service (MMS), and mobile internet with a theoretical maximum transfer speed of 384 kbit/s (48 kB/s).
In 2001, the third-generation (3G) was launched in Japan by NTT DoCoMo on the WCDMA standard.[15] This was followed by 3.5G or 3G+ enhancements based on the high-speed packet access (HSPA) family, allowing UMTS networks to have higher data transfer speeds and capacity. 3G is able to provide mobile broadband access of several Mbit/s to smartphones and mobile modems in laptop computers. This ensures it can be applied to mobile Internet access, VoIP, video calls, and sending large e-mail messages, as well as watching videos, typically in standard-definition quality.
Smartphones have a number of distinguishing features. The International Telecommunication Union measures those with Internet connection, which it calls Active Mobile-Broadband subscriptions (which includes tablets, etc.). In the developed world, smartphones have now overtaken the usage of earlier mobile systems. However, in the developing world, they account for around 50% of mobile telephony.
Feature phone is a term typically used as a retronym to describe mobile phones which are limited in capabilities in contrast to a modern smartphone. Feature phones typically provide voice calling and text messaging functionality, in addition to basic multimedia and Internet capabilities, and other services offered by the user's wireless service provider. A feature phone has additional functions over and above a basic mobile phone, which is only capable of voice calling and text messaging.[18][19] Feature phones and basic mobile phones tend to use a proprietary, custom-designed software and user interface. By contrast, smartphones generally use a mobile operating system that often shares common traits across devices.
The critical advantage that modern cellular networks have over predecessor systems is the concept of frequency reuse allowing many simultaneous telephone conversations in a given service area. This allows efficient use of the limited radio spectrum allocated to mobile services, and lets thousands of subscribers converse at the same time within a given geographic area.
A cellular network mobile phone system gets its name from dividing the service area into many small cells, each with a base station with (for example) a useful range on the order of a kilometer (mile). These systems have dozens or hundreds of possible channels allocated to them. When a subscriber is using a given channel for a telephone connection, that frequency is unavailable for other customers in the local cell and in the adjacent cells. However, cells further away can re-use that channel without interference as the subscriber's handset is too far away to be detected. The transmitter power of each base station is coordinated to efficiently service its own cell, but not to interfere with the cells further away.
Automation embedded in the customer's handset and in the base stations control all phases of the call, from detecting the presence of a handset in a service area, temporary assignment of a channel to a handset making a call, interface with the land-line side of the network to connect to other subscribers, and collection of billing information for the service. The automation systems can control the "hand off" of a customer handset moving between one cell and another so that a call in progress continues without interruption, changing channels if required. In the earliest mobile phone systems by contrast, all control was done manually; the customer would search for an unoccupied channel and speak to a mobile operator to request connection of a call to a landline number or another mobile. At the termination of the call the mobile operator would manually record the billing information.
Mobile phones communicate with cell towers that are placed to give coverage across a telephone service area, which is divided up into 'cells'. Each cell uses a different set of frequencies from neighboring cells, and will typically be covered by three towers placed at different locations. The cell towers are usually interconnected to each other and the phone network and the internet by wired connections. Due to bandwidth limitations each cell will have a maximum number of cell phones it can handle at once. The cells are therefore sized depending on the expected usage density, and may be much smaller in cities. In that case much lower transmitter powers are used to avoid broadcasting beyond the cell.
In order to handle the high traffic, multiple towers can be set up in the same area (using different frequencies). This can be done permanently or temporarily such as at special events or in disasters. Cell phone companies will bring a truck with equipment to host the abnormally high traffic. 0852c4b9a8
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