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NR-Handover From E-UTRA Complete

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The NR-Handover From E-UTRA (LTE) Complete is a technical procedure in 5G networks that describes the successful completion of a handover (also known as a handoff) from the LTE (Long-Term Evolution) network (E-UTRA, Evolved Universal Terrestrial Radio Access) to the 5G NR (New Radio) network. This procedure is crucial for ensuring uninterrupted communication as a mobile device transitions from LTE to 5G. Below is a detailed technical explanation of the NR-Handover From E-UTRA Complete procedure:

Handover Trigger:

  • The NR-Handover From E-UTRA Complete procedure is initiated when specific conditions are met, indicating that a handover from the LTE network to the 5G NR network is necessary. These conditions can include factors like signal quality, cell load, or network policies.

UE and Network Roles:

  • The UE (User Equipment) is the mobile device (e.g., smartphone, IoT device), while the network includes both the LTE eNodeB (base station) and the 5G NR gNodeB (base station), along with core network elements.

Handover Preparation:

  • Before initiating the handover, the network, UE, and potentially neighboring cells prepare for the handover process.
  • The UE may receive measurement configurations instructing it to monitor the 5G NR cells and evaluate their suitability for handover.

Measurement and Evaluation:

  • The UE performs measurements on both the LTE and 5G NR cells to assess their signal quality, interference levels, and other relevant parameters.
  • Based on these measurements, the UE evaluates whether the 5G NR network is a better candidate for handover.

Handover Decision:

  • If the UE determines that the 5G NR network offers a better radio link quality or improved network conditions compared to LTE, it initiates a handover request.

Handover Request Message:

  • The UE sends a Handover Request message to the LTE eNodeB, indicating its intention to perform a handover to the 5G NR network.
  • This message includes information about the target 5G NR cell and relevant handover parameters.

Network Processing:

  • Upon receiving the Handover Request message, the LTE eNodeB evaluates the request and decides whether to initiate the handover.
  • The eNodeB may also allocate resources for the handover and coordinate with the target 5G NR gNodeB.

UE Transition to 5G NR:

  • If the handover is approved, the LTE eNodeB sends a Handover Command message to the UE, instructing it to transition to the 5G NR network.
  • The UE follows the instructions provided in the command to establish a connection with the target 5G NR gNodeB.

Handover Execution:

  • The UE communicates with the 5G NR gNodeB, which may involve adjusting its radio parameters, configuring radio bearers, and establishing synchronization with the new cell.
  • This process ensures a seamless transition from LTE to 5G NR.

Handover Complete Message:

  • Once the handover to the 5G NR network is successfully completed, the UE sends a Handover Complete message to the LTE eNodeB, confirming that it has established a new connection with the target 5G NR gNodeB.

Service Resumption:

  • After the handover is complete, the UE can resume its active services, including data sessions, voice calls, or other communication, using the 5G NR network.

Continuous Monitoring:

  • Both the UE and the network continue to monitor the quality of the 5G NR radio link to ensure its stability and make further adjustments if needed.

In summary, the NR-Handover From E-UTRA Complete procedure in 5G networks allows for a smooth transition of a mobile device from the LTE network to the 5G NR network. It involves measurements, handover decision-making, handover request and command messages, and successful handover execution. This procedure ensures that the UE experiences minimal disruption and can continue its communication using the 5G NR network with improved radio link conditions.