CDMA2000, is a code-division multiple access (CDMA) version of the IMT-2000 standard developed by the International Telecommunication Union (ITU). The CDMA2000 standard is third-generation (3-G) mobile wireless technology. The book represents a comprehensive description of the system architecture and operation of CDMA2000 third-generation wireless communications networks. The book includes a theoretical description of spread spectrum and CDMA technologies. An overview of the entire CDMA2000 network, including CDMA Radio Access Network, Packet Core Network, Mobile Station and the corresponding reference points are given. The focus is on the air interface, reference point between mobile station and base station. In depth explanation of the physical layer protocol design and underlying principles is presented. The material also includes detailed description of the medium access control, IS-2000 Layer 3 signaling, call flows describing end-to-end system operation for circuit switched voice and packet data calls as well as concurrent services.