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Code-division multiple access (CDMA) is a channel access method used by various radio communication technologies. CDMA is an example of multiple access, where several transmitters can send information simultaneously over a single communication channel.
Cellular network standards and generation timeline. This is a comparison of standards of wireless networking technologies for devices such as mobile phones.A new generation of cellular standards has appeared approximately every tenth year since 1G systems were introduced in 1979 and the early to mid-1980s.
However, unlike TDMA, there are no time slots, and all CDMA radios can be active all the time to deliver up to 14.4 kbit/s data transmission speeds. With the evolution of CDMA to CDMA2000 and 1xRTT, the use of IS-95 CDMA Circuit Switched Data declined in favour of the faster data transmission speeds available with the newer technologies.
Spectrum re-allocated for E-GSM 900 (Band 8). ... No new applications for CDMA service were accepted after 7 Nov 2018. ... Only data services.
Multi-carrier code-division multiple access (MC-CDMA) is a multiple access scheme used in OFDM-based telecommunication systems, allowing the system to support multiple users at the same time over same frequency band. MC-CDMA spreads each user symbol in the frequency domain.
The Universal Mobile Telecommunications System (UMTS) is a 3G mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the International Telecommunication Union IMT-2000 standard set and compares with the CDMA2000 standard set for networks based on the competing cdmaOne technology.
An encryption key is also generated that is subsequently used to encrypt all wireless communications (voice, SMS, etc.) between the mobile phone and the GSM core network. If the authentication fails, then no services are possible from that particular combination of SIM card and mobile phone operator attempted.
Initial synchronization of a phone requires even more care. Before a mobile transmits there is no way to know the offset required. For this reason, an entire time slot has to be dedicated to mobiles attempting to contact the network; this is known as the random-access channel (RACH) in GSM. The mobile transmits at the beginning of the time slot ...