Question: In Inter-RAT (Radio Access Technology) handovers to E-UTRAN, how does a UE (User Equipment) perform E-UTRAN measurements when handing over from a GERAN (GSM/EDGE Radio Access Network)?
Option 1: Using dedicated measurement gaps in the GERAN frame structure.
Option 2: In GSM idle frames in a time multiplexed manner, similar to WCDMA measurements for handover to UTRAN.
Option 3: By employing compressed mode (CELL_DCH) or DRX (Discontinuous Reception) in GERAN.
Option 4: Based on a measurement configuration decided by the GERAN Base Station Controller.
Explanation: This is correct because, when a UE hands over from GERAN to E-UTRAN, it utilizes GSM idle frames in a time-multiplexed approach, mirroring WCDMA measurements for UTRAN handovers, ensuring seamless integration and efficient resource use during the handover process between different radio access technologies.