Who makes the Handover Decision in LTE?
In LTE, the handover process is a critical aspect of maintaining seamless communication as a user moves between different cells. To understand who makes the handover decision, let’s first break down the handover process and how it works in LTE networks.
When you are using a mobile device in an LTE network, your device constantly connects to a cell tower (eNodeB). As you move around, the signal strength from the cell tower you’re connected to may weaken, and the signal from another tower might become stronger. When this happens, the network needs to decide whether to hand over your connection to the new cell to maintain the best service quality. This is where the handover decision comes into play.
The decision of when and how to perform a handover in LTE is primarily made by the eNodeB (evolved NodeB), which is the base station responsible for managing the radio interface. However, the actual handover process involves collaboration between different elements of the LTE network, including the eNodeB and the MME (Mobility Management Entity).
Here’s a step-by-step breakdown of who makes the decision:
- eNodeB (evolved NodeB): The eNodeB monitors the signal quality of the user equipment (UE) in its coverage area. If the signal strength drops below a certain threshold, the eNodeB may initiate a handover to a neighboring cell with better signal quality. The eNodeB will evaluate which neighboring cell offers the best connection options and send a handover request to that cell.
- MME (Mobility Management Entity): Although the eNodeB plays a major role in initiating the handover, the MME is involved in managing the overall mobility of the UE. It communicates with the eNodeB to confirm the handover procedure, and it ensures that the UE’s context is properly transferred to the new cell. The MME also plays a role in security and authentication during the handover process.
- Handover Decision Process: The actual decision to trigger a handover is based on the measurement reports from the UE, the signal strength from surrounding cells, and the load on the neighboring cells. The eNodeB assesses these reports and determines whether the current cell can still provide optimal service or whether it is time to switch the connection to a new cell.
In summary, the eNodeB is the primary entity that makes the handover decision based on real-time measurements, but it works closely with the MME to ensure the handover is smooth and efficient. This collaboration ensures that as you move around in the LTE network, your service remains uninterrupted and at its best quality.