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In 3G, the most prevalent technology was UMTS with CDMA-2000 in close contention. All radio access technologies have to solve the same problems: to divide the finite RF spectrum among multiple users as efficiently as possible. GSM uses TDMA and FDMA for user and cell separation. UMTS, IS-95 and CDMA-2000 use CDMA. WiMAX and LTE use OFDM.
CDMA is analogous to the last example where people speaking the same language can understand each other, but other languages are perceived as noise and rejected. Similarly, in radio CDMA, each group of users is given a shared code. Many codes occupy the same channel, but only users associated with a particular code can communicate.
CDMA2000 1X (IS-2000), also known as 1x and 1xRTT, is the core CDMA2000 wireless air interface standard.The designation "1x", meaning 1 times radio transmission technology, indicates the same radio frequency (RF) bandwidth as IS-95: a duplex pair of 1.25 MHz radio channels. 1xRTT almost doubles the capacity of IS-95 by adding 64 more traffic channels to the forward link, orthogonal to (in ...
CDMA2000 1xRTT, EV-DO Rev. B 450 2012: Dec 2014 [76] [77] [78] csl Hong Kong: CDMA2000 1xRTT, EV-DO Rev. A 800 Nov 2008: Oct 2017 [79] [80] [81] Provider formerly branded as PCCW. CDMA service suspended starting from 31 October 2017. BSNL India: CDMA2000 1xRTT, EV-DO Rev. A 800 Mar 2005: Mar 2016 [82] [83] [84] MTS India: CDMA2000 1xRTT, EV-DO ...
UMTS W-CDMA HSPA (HSDPA+HSUPA) 3GPP: Mobile Internet: CDMA/FDD CDMA/FDD/MIMO: 0.384 14.4: 0.384 5.76: HSDPA is widely deployed. Typical downlink rates today 2 Mbit/s, ~200 kbit/s uplink; HSPA+ downlink up to 56 Mbit/s. UMTS-TDD: 3GPP: Mobile Internet: CDMA/TDD: 16: Reported speeds according to IPWireless using 16QAM modulation similar to HSDPA ...
In 1999 ITU approved five radio interfaces for IMT-2000 as a part of the ITU-R M.1457 Recommendation. [4] The five standards are: [5] IMT-2000 CDMA Direct Spread. also known as W-CDMA, used in UMTS, the successor to GSM; IMT-2000 CDMA Multi-Carrier. also known as CDMA2000, the successor to 2G CDMA ; IMT-2000 CDMA TDD. also known as TD-SCDMA
CDG – CDMA Development Group ... IS-2000 – Superseded by TIA-2000. ... WCDMA – Wideband Code Division Multiple Access X
CDMA frequency bands or frequency ranges are the cellular frequencies designated by the ITU for the operation ... 2.5 GHz IMT-2000 Extension: 2500 - 2570: 2620 - 2690 ...