The primary objective of 2G networks was to provide mobile circuit-switched voice and low rate data services while the main goal of the evolution to 3G networks was the packet switched data via cellular systems as well as increased voice capacity. As demand for both greater capacity and more packet data services increased, the efforts were made to improve 3G data throughput as achieved 2 Mbps in WCDMA radio access technique and at the same time enhancing voice performance over the same RF carrier.

The CDMA 2000 air (radio) interface was proposed in IMT 2000 standard based on CDMA and FDD techniques to satisfy the needs of 3G wireless communication system. The CDMA 2000 system is backward compatible with the current CDMAOne (IS-95) family of standards. CDMA One is the family of standards of CDMA technology consisting of IS-95, IS-95A (J-STD-008) and IS-95B and is based on the original 1.25 MHz channel bandwidth per user.