Code-division multiple access (CDMA), also known as "spread spectrum", is a form of multiplexing where the transmitter encodes the signal using a pseudorandom sequence which the receiver also knows and can use to decode the received signal. Each different random sequence corresponds to a different communication channel.
History[]
Qualcomm pioneered the introduction of CDMA in wireless 2G telephone services. Motorola used CDMA for their digital mobile phones.[1] Verizon and Sprint Corporation adopted CDMA2000 for their respective 3G networks.[2] The version of the iPhone 4 released through Verizon was the first mobile device from Apple to support CDMA.[3]
Retirement of 3G service[]
Verizon is scheduled to shut down its CDMA-based 3G network on December 31, 2022 to make room for more advanced wireless services.[4][5] T-Mobile shut down Sprint Corporation's old CDMA network on March 31, 2022.[6][7] This affects all older iPhone models that do not support Voice over LTE (iPhone 5C, 5S and earlier). This also affects the CDMA version of the iPad 2.[8]
References[]
- ↑ Code Division Multiple Access at the Free On-Line Dictionary Of Computing. 2006-04-29.
- ↑ CDMA History, CDG. Accessed 2021-10-10.
- ↑ Verizon Wireless Finally Gets Apple's iPhone by Sam Gustin, Wired. 2011-01-11.
- ↑ 3G CDMA Network Shut off date set for December 31, 2022, Verizon. 2021-03-30.
- ↑ Plan Ahead for Phase Out of 3G Cellular Networks and Service, Federal Communications Commission. 2021-08-23.
- ↑ T-Mobile will shut down Sprint's 3G network in March by Mikey Campbell, AppleInsider. 2021-10-22.
- ↑ T-Mobile Network Evolution, T-Mobile. Accessed 2022-10-04.
- ↑ T-Mobile Network Evolution, T-Mobile. Accessed 2021-10-10.
See also[]
- Global System for Mobile Communications (GSM), a competing standard.
External links[]
- CDMA2000 at CDG
- Code-division multiple access (CDMA) at the Telecommunications Industry Association
- CDMA and CDMA2000 at Wikipedia
