Supplementary Cell Reconfiguration for Fast Primary Cell Recovery
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Solution Overview
Problem
Existing wireless communication networks face challenges in quickly recovering from primary cell failures, leading to increased latency and service interruptions due to the time-consuming RRC Reestablishment procedure, particularly in scenarios involving single connectivity and radio link failures near cell edges.
Innovation Solution
Implementing a supplementary cell (SuC) that can rapidly configure as a new PCell using supplementary downlink (SDL) and uplink (SUL) carriers or carrier aggregation (CA) to restore the radio link, enabling fast PCell recovery even when the UE or network does not support legacy RRC reestablishment procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the RRC Reestablishment procedure is used for primary cell failure recovery, then the radio link can be restored, but the service interruption time is increased due to the time-consuming nature of the procedure
Solution Approach 1:
The network pre-configures supplementary cells (SuC) and their associated carriers (SDL/SUL) before primary cell failure occurs. When failure happens, the UE can immediately activate the pre-configured SuC without waiting for RRC reestablishment, thus reducing service interruption time while ensuring reliable radio link restoration
Solution Approach 2:
The supplementary cell acts as an intermediary mechanism between the failed primary cell and the RRC reestablishment procedure. The SuC provides a fast recovery path that mediates the transition from failed PCell to restored connectivity, bypassing the lengthy traditional reestablishment process
2Loss of time
If a supplementary cell with SDL and SUL carriers is configured for fast PCell recovery, then the service interruption time is reduced, but the device complexity increases
Solution Approach 1:
The supplementary cell is designed with multi-functionality, serving both as a regular secondary cell for carrier aggregation and as a fast recovery primary cell when needed. This universal design allows the same SuC infrastructure to handle both normal operation and failure recovery scenarios, reducing the need for separate dedicated recovery mechanisms and thereby limiting the increase in device complexity
3Reliability
If dual connectivity scenarios are implemented to maintain connectivity during mobility, then the service continuity is improved, but the network complexity increases
Solution Approach 1:
The network is segmented into master node and secondary node components, with the SuC functioning as a specialized secondary node. This segmentation allows independent management and configuration of recovery resources at the secondary node level, simplifying the overall network architecture by isolating the fast recovery functionality from the core RRC management functions at the master node
Data Source
AI summary
Described herein are solutions for fast primary cell (PCell) recovery using a supplementary cell (SuC) to configure a new PCell to restore a failed radio link between a user equipment (UE) and a PCell. The UE can detect a radio link failure (RLF) corresponding to the PCell and use a SuC to recover connectivity with another PCell. The UE can send PCell failure information to the SuC and, in response to the PCell failure information, the network can configure another cell to operate as a PCell for the UE. The new PCell can be a special cell (SpCell) configured with PCell configuration information, the SuC configured with PCell configuration information, or another type of cell. These and many other features and examples are described herein.