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Channel access method
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=== Cellular networks === In [[cellular networks]] the two most widely adopted technologies are CDMA and TDMA. TDMA technology works by identifying natural breaks in speech and utilizing one radio wave to support multiple transmissions in turn. In CDMA technology, each individual packet receives a unique code that is broken up over a wide frequency spectrum and is then reassembled on the other end. CDMA allows multiple people to speak at the same time over the same frequency, allowing more conversations to be transmitted over the same amount of spectrum; this is one reason why CDMA eventually became the most widely adopted channel access method in the wireless industry.<ref name=":0">{{Cite web|url=https://www.qualcomm.com/invention/stories/world-changing-technology|title=The world-changing technology that almost wasn't|last=Qualcomm|first=Qualcomm|website=Qualcomm}}</ref> The origins of CDMA can be traced back to the 1940s where it was patented by the United States government and used throughout World War II to transmit messages. However, following the war the patent expired and the use of CDMA diminished and was widely replaced by TDMA.<ref name=":0" /> That was until [[Irwin M. Jacobs]] an MIT engineer, and fellow employees from the company [[Linkabit]] founded the telecommunications company [[Qualcomm]].<ref>{{Cite news|url=https://www.wsj.com/articles/SB10001424052970204879004577111313063790248|title=Qualcomm Founder Set to Retire|last=Tibken|first=Shara|date=2011-12-21|work=Wall Street Journal|access-date=2019-12-03|language=en-US|issn=0099-9660}}</ref> At the time Qualcomm was founded, Jacobs had already been working on addressing telecommunications problems for the military using digital technology to increase the capacity of spectrum.<ref name=":1">{{Cite book|url=https://books.google.com/books?id=JcH4C2eAsJEC&q=%25E2%2580%259CDisrupting%2520the%2520Cellular%2520Status%2520Quo%2520Qualcomm%2520Goes%2520to%2520Bat%252C%25201989%25E2%2580&pg=PR5|title=The Qualcomm Equation: How a Fledgling Telecom Company Forged a New Path to Big Profits and Market Dominance|last=Mock|first=Dave|date=2005|publisher=Amacom|isbn=978-0-8144-2858-0|language=en}}</ref> Qualcomm knew that CDMA would greatly increase the efficiency and availability of wireless, but the wireless industry having already invested millions of dollars into TDMA was skeptical.<ref name=":1" /> Jacobs and Qualcomm spent several years improving infrastructure and performing tests and demonstrations of CDMA. In 1993, CDMA became accepted as the wireless industry standard. By 1995, CDMA was being used commercially in the wireless industry as the foundation of [[2G]].<ref name=":0" />
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