Also known as: CDMA2000, 1xRTT, IS-2000, CDMA 1x
CDMA2000 is the 3G cellular family descended from the IS-95 (cdmaOne) system, using 1.25 MHz CDMA carriers and standardised by 3GPP2. Its baseline voice and data mode, 1xRTT, roughly doubled the capacity of IS-95, while the EV-DO companion standard added a dedicated high-rate data carrier.1
Overview
CDMA2000 is the North-American-led branch of 3G, competing with UMTS/W-CDMA. It kept the narrow 1.25 MHz carrier of its IS-95 predecessor — a deliberate choice that let operators upgrade in-band without new spectrum — and applied direct-sequence CDMA with the same tight power control. The “1x” in 1xRTT means one such carrier; a later multi-carrier variant (3x) was specified but little deployed. Voice used the EVRC and QCELP vocoders.
Technical characteristics
| Property | Value |
|---|---|
| Generation | 3G (IS-95 lineage) |
| Access | Direct-sequence CDMA |
| Carrier spacing | 1.25 MHz |
| Chip rate | 1.2288 Mchip/s |
| Voice mode | 1xRTT (IS-2000) |
| Data mode | EV-DO (1xEV-DO) |
| Vocoder | EVRC, QCELP |
| Duplex | FDD (paired) |
The narrow carrier and 1.2288 Mchip/s spreading rate are the enduring signatures of the whole IS-95/CDMA2000 family.
History
IS-95 (cdmaOne), championed by Qualcomm, brought commercial CDMA to cellular in the mid-1990s. Its 3G successor CDMA2000 1xRTT launched around 2000 under the 3GPP2 partnership, followed by EV-DO for high-speed data. The technology was strong in the United States, South Korea, and parts of Asia and Latin America.
Deployment
Major CDMA2000 operators included carriers in the US, South Korea, and elsewhere who had built on IS-95. Because the ecosystem was smaller than the GSM family and lacked a removable-SIM tradition, most operators migrated to LTE for 4G and have since shut down their CDMA2000 networks, reclaiming the 1.25 MHz carriers.
Decoding it with GopherTrunk
GopherTrunk targets trunked land-mobile and utility signals; cellular telephony such as CDMA2000 is out of scope and is not decoded. Its carriers hold private, authenticated, ciphered subscriber traffic on licensed spectrum. CDMA2000 is listed here to complete the 3G picture and to contrast the IS-95 CDMA lineage with the W-CDMA branch.