Question: In a Handover scenario between a Relay Node (RN) and a neighboring eNodeB (eNB), what influences the RN's decision to initiate either S1 or X2 handover for a User Equipment (UE), in addition to the procedures specified for inter-eNB handovers?
Option 1: GUMMEI of the UE's serving Mobility Management Entity (MME) provided by the Donor eNB (DeNB), GU Group ID of the neighbor eNB, and X2 interface availability between DeNB and neighbor eNB.
Option 2: Only the GU Group ID of the neighbor eNB and the availability of the S1 interface between the RN and the neighbor eNB.
Option 3: The UE's current QoS requirements and the neighbor eNB's current load conditions, as signaled through the X2 interface.
Option 4: Random selection between S1 and X2 handover to distribute the handover traffic evenly.
Explanation: This is because the provided GUMMEI of the UE's serving MME by the DeNB, along with the GU Group ID of the neighbor eNB and the availability of the X2 interface between the DeNB and the neighbor eNB, collectively provide the RN with sufficient information to make an informed decision about whether to initiate S1 or X2 handover for optimal network efficiency and resource utilization. This aligns with efficient mobility management practices in E-UTRAN, ensuring seamless connectivity for UEs.