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A mobile phone (also known as a cell phone or cellular phone) is a telephone which can make and receive calls over a radio frequency carrier while the user is moving within a telephone service area. 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). A modern mobile telephone service uses a cellular network architecture. In addition to telephony, modern mobile phones support a variety of other services, such as text messaging, MMS, email, Internet access, short-range wireless communications (infrared, Bluetooth), business applications, gaming, and photography. Mobile phones which offer these and more general computing capabilities are referred to as smartphones. The first handheld mobile phone was demonstrated by John F. Mitchell〔(John F. Mitchell Biography )〕〔(Who invented the cell phone? )〕 and Martin Cooper of Motorola in 1973, using a handset weighing around 4.4 lbs (2 kg). 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, penetrating 100% of the global population and reaching the bottom of the economic pyramid. In 2014, the top mobile phone manufacturers were Samsung, Nokia, Apple, and LG.〔(【引用サイトリンク】title=Top 10 Best-selling Mobile Phone Brands in the World 2014 )〕 == History == (詳細は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 "0G" (zeroth generation) services, such as Bell System's Mobile Telephone Service and its successor, the Improved Mobile Telephone Service. These "0G" systems were not cellular, supported few simultaneous calls, and were very expensive. The first handheld mobile cell phone was demonstrated by Motorola in 1973. The first commercial automated cellular network 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.〔(【引用サイトリンク】title=Swedish National Museum of Science and Technology )〕 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 technology. 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. Ten years later, in 2001, the third generation (3G) was launched in Japan by NTT DoCoMo on the WCDMA standard. This was followed by 3.5G, 3G+ or turbo 3G enhancements based on the high-speed packet access (HSPA) family, allowing UMTS networks to have higher data transfer speeds and capacity. By 2009, it had become clear that, at some point, 3G networks would be overwhelmed by the growth of bandwidth-intensive applications, such as streaming media. Consequently, the industry began looking to data-optimized fourth-generation technologies, with the promise of speed improvements up to ten-fold over existing 3G technologies. The first two commercially available technologies billed as 4G were the WiMAX standard, offered in North America by Sprint, and the LTE standard, first offered in Scandinavia by TeliaSonera. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Mobile phone」の詳細全文を読む スポンサード リンク
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