 shows the evolution of the CDMA 2000 standard, CDMA2000 1X, which is based on the IS-2000 standard. It: is backward compatible with the original cdmaOne offers up to twice the voice capacity of cdmaOne systems supports always-on packet-data sessions provides data rates of up to 144 kbit/s - with peak over-the-air data rates (including overhead) of 163.2 kbit/s (IS-2000 Rev. 0) and 307.2 kbit/s (IS-2000 Rev. A). Beyond CDMA2000 1X, the Third Generation Partnership Project 2 (3GPP2) specifies two (1xEV) standards: 1xEV-DO (data only) and 1xEV-DV (data and voice). CDMA2000 1xEV-DO comprises a separate data carrier that provides best-effort packet- data service with a peak over-the-air data rate of 2.4 Mbit/s. CDMA2000 1xEV-DV provides integrated voice and data with real-time data services and a peak over-the-air data rate of 3.1 Mbit/s. The main radio network parts are: a base station controller radio base stations a radio network management system CDMA2000 1XEV-DV 1XEV-DO effort voice Mbit/s 153.6 kbit/s Figure 13.30 Evolution within the CDMA systems Understanding Changing Telecommunications - Building a Successful Telecom Business Packet data serving/service node RNM radio network manager Other CDMA2000 CDMA 2000 management system Mobile station Figure 13.31 A CDMA access network structure Typical base station controller functions are: control of the radio base stations, man- agement of radio network resources and provision of user mobility. Base station controllers may also perform voice compression (vocoding), process han- dovers, manage power control to ensure efficient use of network capacity, control timing and synchronization within the radio access network, and provide interfaces to the radio base stations, the radio network manager and packet-data service/serving nodes (PDSN). The radio base stations provide the radio resources. A key feature of CDMA2000 1X packet-data service is that the packet-data connection between the mobile station and the network is always on. The CDMA access network structure is s