Question: What is the primary purpose of the "Mobility to non-3GPP radio system" function in E-UTRAN, specifically regarding CDMA2000 systems?
Option 1: To enhance security protocols for data transmission between LTE and CDMA2000 networks.
Option 2: To facilitate the upgrade of CDMA2000 infrastructure to support LTE frequencies.
Option 3: To manage Quality of Service (QoS) parameters for voice calls between E-UTRAN and CDMA2000 systems.
Option 4: To enable seamless handover and pre-registration signaling for UEs moving between E-UTRAN and CDMA2000 HRPD/1xRTT networks.
Explanation: The correct answer, Option 4, highlights the key functionality of supporting mobility (handovers and pre-registration) between E-UTRAN (LTE) and non-3GPP CDMA2000 systems (HRPD/1xRTT), ensuring continuous connectivity for UEs transitioning between these networks. This is crucial for maintaining service continuity in heterogeneous network environments.