Sign in Subscribe

RRC Connection Resume Complete

Last updated on 


The RRC (Radio Resource Control) Connection Resume Complete is a technical procedure in LTE (Long-Term Evolution) and 5G mobile telecommunications networks. It occurs when a User Equipment (UE) that has previously been in an RRC idle state and in a lower-power mode (e.g., RRC Inactive) needs to resume an active RRC connection with the network. This procedure allows the UE to re-establish communication with the network while conserving power when not actively transmitting data. Here's a technical explanation of the RRC Connection Resume Complete procedure:

1. RRC Inactive State:

  • Power-Saving Mode: The UE enters the RRC Inactive state to conserve power when there is no ongoing data transmission or reception. In this state, the UE is not actively connected to the network.

2. Trigger for RRC Connection Resume:

  • Data to Transmit/Receive: When there is data to transmit or receive, or when the UE needs to re-establish an active connection with the network (e.g., due to network paging or a network-initiated event), the UE decides to exit the RRC Inactive state.

3. RRC Connection Resume Request:

  • UE Initiates Request: The UE initiates an RRC Connection Resume Request message to inform the network that it wishes to resume an active RRC connection.
  • Message Contents: The message typically includes information about the UE's capabilities and requirements, such as supported radio bearers and service requirements.

4. Network Handling:

  • Message Reception: The network's eNodeB (in LTE) or gNodeB (in 5G) receives the RRC Connection Resume Request message from the UE.
  • Capability Assessment: The network assesses the UE's capabilities and requirements to determine if it can accommodate the requested connection.

5. RRC Connection Resume Acceptance:

  • Network Response: If the network can accommodate the UE's request, it generates an RRC Connection Resume Acceptance message.
  • Message Contents: The message includes information about the granted radio resources and parameters for the resumed connection.

6. Message Signaling:

  • Response to UE: The RRC Connection Resume Acceptance message is sent back to the UE over the radio interface.

7. UE Processing:

  • Message Reception: The UE receives the RRC Connection Resume Acceptance message and processes it.
  • Context Activation: The UE configures its context based on the received parameters, including radio bearers and parameters for communication.

8. RRC Connection Resumption:

  • UE to Network Transition: The UE transitions from the RRC Inactive state to an active RRC connection state, allowing it to send and receive data.
  • Communication Resumption: The UE can now actively communicate with the network, including sending and receiving data, based on the granted resources.

9. Continued Operation:

  • Data Transfer: The UE can continue its communication session, transmit and receive data, and participate in network services.

10. Power Optimization:

  • Resource Management: The UE can revert to the RRC Inactive state when data transmission or reception is complete to conserve power until the next data transfer event or network interaction.

The RRC Connection Resume Complete procedure is essential for enabling efficient power management in mobile devices, ensuring that they remain in low-power states when not actively communicating while allowing for a quick and seamless transition to an active connection when needed.