5g sa handover call flow

The 5G Standalone (SA) handover call flow involves the transfer of an ongoing communication session from one cell to another as a user moves through the network. The handover process is crucial to maintain seamless connectivity and optimal performance for mobile devices. Below is a technical explanation of the 5G SA handover call flow:

1. Event Triggering:
   • Handovers can be triggered by various events, such as a user moving out of the coverage area of the current cell or experiencing deteriorating signal quality. These triggers are monitored by the network to initiate the handover process.
2. Measurement Reporting:
   • The user equipment (UE) continuously measures the signal quality and reports these measurements to the source cell (the cell the device is currently connected to). The measurements include parameters like signal strength, signal quality, and interference.
3. Handover Decision:
   • The source cell evaluates the measurement reports to decide whether a handover is necessary. The decision might involve selecting a target cell that offers better signal quality or has more available resources.
4. Handover Request (RRC Connection Reconfiguration):
   • If the source cell determines that a handover is needed, it sends a handover request to the target cell. This request includes information about the user, the current communication session, and the reason for the handover.
5. Target Cell Preparation:
   • The target cell prepares for the handover by allocating resources and configuring the necessary parameters for the incoming UE. This involves setting up the radio bearers and other protocols required for the communication session.
6. Handover Command to UE:
   • The source cell sends a handover command to the UE, instructing it to switch to the target cell. This command is part of the Radio Resource Control (RRC) connection reconfiguration message and includes information about the target cell.
7. Handover Execution:
   • The UE follows the instructions in the handover command and performs the necessary actions to switch its connection to the target cell. This involves reconfiguring its radio bearers, adjusting transmission parameters, and updating its synchronization with the new cell.
8. Handover Confirmation:
   • The target cell acknowledges the handover by sending a handover confirmation to the source cell. This confirms that the UE has successfully transitioned to the target cell.
9. Data Path Switch:
   • The data path is switched from the source cell to the target cell. This ensures that the ongoing communication session is maintained without interruption.
10. Handover Completion:

• Both the source and target cells complete the handover process, releasing any resources that were allocated for the previous connection.