Dual Connectivity Downlink Control for SCG Radio Link Failure

The patent introduces a signaling mechanism where the gNB-CU-CP acts as an intermediary that receives SCG failure information from the gNB-DU and forwards it to the gNB-CU-UP. This mediator approach allows the control plane to communicate failure information to the user plane without requiring direct signaling between components that would increase system complexity.

The patent segments the base station into distinct functional units (gNB-CU-CP, gNB-CU-UP, gNB-DU) with specific responsibilities. The gNB-CU-CP handles control plane functions including receiving and forwarding failure information, while the gNB-CU-UP handles user plane functions including pausing data transmission. This segmentation allows each component to perform its specialized function without increasing overall system complexity.

The patent implements preliminary action by having the gNB-CU-UP pause downlink data transmission immediately upon receiving the SCG failure information from the gNB-CU-CP, before attempting radio link recovery. This preliminary pause prevents data transmission during the failure condition, ensuring reliability while minimizing the time that unreliable transmission could occur.

The patent establishes a feedback mechanism where the gNB-DU detects radio link failure and sends failure information to the gNB-CU-CP, which then notifies the gNB-CU-UP to pause transmission. When the radio link is recovered, the process reverses with recovery information flowing back through the same path, allowing the gNB-CU-UP to resume transmission. This feedback loop ensures timely response to changing radio conditions while maintaining clear communication channels.