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This history focuses on communication devices which connect wirelessly to the public switched telephone network. The transmission of speech by radio has a long and varied history going back to Reginald Fessenden's invention and shore-to-ship demonstration of radio telephony. The first mobile telephones were barely portable compared to today's compact hand-held devices. Along with the process of developing more portable technology, drastic changes have taken place in the networking of wireless communication and the prevalence of its use. ==Predecessors== Before the devices that are now referred to as mobile phones existed, there were some precursors. In 1908 a Professor Albert Jahnke and the Oakland Transcontinental Aerial Telephone and Power Company claimed to have developed a wireless telephone. They were accused of fraud and the charge was then dropped, but they do not seem to have proceeded with production. Beginning in 1918 the German railroad system tested wireless telephony on military trains between Berlin and Zossen. In 1924, public trials started with telephone connection on trains between Berlin and Hamburg. In 1925, the company was founded to supply train telephony equipment and in 1926 telephone service in trains of the Deutsche Reichsbahn and the German mail service on the route between Hamburg and Berlin was approved and offered to 1st class travelers.〔Informatikzentrum Mobilfunk (IZMF). (izmf.de: "The development of digital mobile communications in Germany" ), retrieved on 2013-05-30〕 In 1907, the English caricaturist Lewis Baumer published a cartoon in Punch magazine entitled "Predictions for 1907" in which he showed a man and a woman in London's Hyde Park each separately engaged in gambling and dating on wireless telephony equipment. Then in 1926 the artist Karl Arnold created a visionary cartoon about the use of mobile phones in the street, in the picture "wireless telephony", published in the German satirical magazine Simplicissimus.〔(simplicissimus.info: Bild „Drahtlose Telephonie" ) in Simplicissimus, 1926 (Jg. 31) Heft 38, S. 498., (PDF-file), retrieved on 2012-03-14〕 The portrayal of a utopia of mobile phone in literature dates back to the year 1931. It is found in Erich Kästner's children's book ''The 35th of May, or Conrad's Ride to the South Seas'': The Second World War made military use of radio telephony links. Hand-held radio transceivers have been available since the 1940s. Mobile telephones for automobiles became available from some telephone companies in the 1940s. Early devices were bulky and consumed high power and the network supported only a few simultaneous conversations. Modern cellular networks allow automatic and pervasive use of mobile phones for voice and data communications. In the United States, engineers from Bell Labs began work on a system to allow mobile users to place and receive telephone calls from automobiles, leading to the inauguration of mobile service on 17 June 1946 in St. Louis, Missouri. Shortly after, AT&T offered ''Mobile Telephone Service''. A wide range of mostly incompatible mobile telephone services offered limited coverage area and only a few available channels in urban areas. The introduction of cellular technology, which allowed re-use of frequencies many times in small adjacent areas covered by relatively low powered transmitters, made widespread adoption of mobile telephones economically feasible. One of the earliest fictional descriptions of a mobile phone can be found in the 1948 science fiction novel Space Cadet by Robert Heinlein. The protagonist, who has just traveled to Colorado from his home in Des Moines, receives a call from his father on a pocket telephone. Before going to space he decides to ship the telephone home “since it was limited by its short range to the neighborhood of an earth-side (terrestrial ) relay office.” Ten years later, an essay by Arthur C. Clarke envisioned a "personal transceiver, so small and compact that every man carries one." He wrote: "the time will come when we will be able to call a person anywhere on Earth merely by dialing a number." Such a device would also, in Clarke's vision, include means for global positioning so that "no one need ever again be lost." Later, in ''Profiles of the Future'', he predicted the advent of such a device taking place in the mid-1980s.〔Arthur C. Clarke: ''Profiles of the Future'' (1962, rev. eds. 1973, 1983, and 1999, Millennium edition with a new preface)〕 US TV series Get Smart (1965-1970) depicted spy gadgets with mobile telephones concealed in random objects, including shoes. In the USSR, Leonid Kupriyanovich, an engineer from Moscow, in 1957-1961 developed and presented a number of experimental models of handheld mobile phones. The weight of one model, presented in 1961, was only 70 g and could fit on a palm.〔(Мартин Купер был не первым. ) Олег Измеров (in Russian).〕 However, in the USSR the decision at first to develop the system of the automobile "Altai" phone was made. 〔"Nauka i zhizn" magazine, 8, 1957 and 10, 1958; "Technika-molodezhi" magazine, 2, 1959; "Za rulem" magazine, 12, 1957, "Yuny technik" magazine, 7, 1957, 2, 1958 and 9, 1996; "Orlovskaya pravda" newspaper, 12, 1961.〕 In 1965, Bulgarian company "Radioelektronika" presented on the Inforga-65 international exhibition in Moscow the mobile automatic phone combined with a base station. Solutions of this phone were based on a system developed by Leonid Kupriyanovich. One base station, connected to one telephone wire line, could serve up to 15 customers. 〔"Nauka i zhizn" magazine, 8, 1965.〕 The advances in mobile telephony can be traced in successive ''generations'' from the early "0G" services like MTS and its successor Improved Mobile Telephone Service, to first generation (1G) analog cellular network, second generation (2G) digital cellular networks, third generation (3G) broadband data services to the current state of the art, fourth generation (4G) native-IP networks. 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「History of mobile phones」の詳細全文を読む スポンサード リンク
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