Editing Code-division multiple access (section)

===Soviet Union===
In the [[Soviet Union]] (USSR), the first work devoted to this subject was published in 1935 by [[Dmitry Vasiliyevich Ageev|Dmitry Ageev]].<ref>{{cite journal|last=Ageev|first=D. V.|title=Bases of the Theory of Linear Selection. Code Demultiplexing|journal=Proceedings of the Leningrad Experimental Institute of Communication|year=1935|pages=3–35}}</ref> It was shown that through the use of linear methods, there are three types of signal separation: frequency, time and compensatory.{{clarify|date=August 2020|reason=No such thing.}} The technology of CDMA was used in 1957, when the young military radio engineer [[Leonid Kupriyanovich]] in Moscow made an experimental model of a wearable automatic mobile phone, called LK-1 by him, with a base station.<ref>{{Cite patent | country = Soviet Union
| number = 115494 | title = Устройства вызова и коммутации каналов радиотелефонной связи (Devices for calling and switching radio communication channels) | pubdate = 1957-11-04 | inventor = Куприянович (Leonid Kupriyanovich) | url = https://patents.su/7-115494-ustrojjstva-vyzova-i-kommutacii-kanalov-radiotelefonnojj-svyazi.html}}</ref> LK-1 has a weight of 3&nbsp;kg, 20–30&nbsp;km operating distance, and 20–30 hours of battery life.<ref>''[[Nauka i Zhizn]]'' 8, 1957, p. 49.</ref><ref>''Yuniy technik'' 7, 1957, p. 43–44.</ref> The base station, as described by the author, could serve several customers. In 1958, Kupriyanovich made the new experimental "pocket" model of mobile phone. This phone weighed 0.5&nbsp;kg. To serve more customers, Kupriyanovich proposed the device, which he called "correlator."<ref>''Nauka i Zhizn'' 10, 1958, p. 66.</ref><ref>''[[Tekhnika Molodezhi]]'' 2, 1959, p. 18–19.</ref> In 1958, the USSR also started the development of the "[[Altai (mobile telephone system)|Altai]]" national civil mobile phone service for cars, based on the Soviet MRT-1327 standard. The phone system weighed {{convert|11|kg|abbr=on}}.  It was placed in the trunk of the vehicles of high-ranking officials and used a standard handset in the passenger compartment. The main developers of the Altai system were VNIIS (Voronezh Science Research Institute of Communications) and GSPI (State Specialized Project Institute). In 1963 this service started in Moscow, and in 1970 Altai service was used in 30 USSR cities.<ref>{{cite web|url=http://englishrussia.com/2006/09/18/first-russian-mobile-phone/|title=First Russian Mobile Phone|date=September 18, 2006}}</ref>