Carrier Aggregation Handover for Zero-Outage User-Plane Data
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing handover procedures in carrier aggregation (CA) and dual connectivity (DC) deployments in 5G networks result in user-plane outages due to the release of secondary cells during primary cell handover, leading to service interruptions, particularly in scenarios where channel qualities between cells differ.
Innovation Solution
Maintain data communication over secondary cells or secondary cell groups during primary cell handover by configuring them with PDCCH and PUCCH channels, and utilizing PDSCH and PUSCH for data transmission, while temporarily lifting logical channel mapping restrictions and employing additional reliability measures like increased transmission power and diversity techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If secondary cells are released during primary cell handover, then handover procedure is simplified, but user-plane data communication is interrupted
Solution Approach 1:
The patent segments the handover process into two independent parts: control plane handover (primary cell) and user plane continuity (secondary cell). By separating these functions, the primary cell can be handed over while the secondary cell maintains data communication, resolving the contradiction between procedure simplicity and data continuity.
Solution Approach 2:
The secondary cell acts as an intermediary that bridges the gap during handover. It receives data from the source gNB and forwards it to the target gNB, ensuring continuous user-plane data communication while the control plane performs handover procedures.
2Ease of operation
If control plane and user plane are handled via same carrier, then procedure is simple, but handover causes service interruption
Solution Approach 1:
The patent divides the communication into control plane (signaling) and user plane (data) components, handling them via different carriers. The control plane uses the primary cell for handover signaling, while the user plane continues via the secondary cell, eliminating service interruption.
Solution Approach 2:
The secondary cell maintains continuous user-plane data transmission during the handover process. Data flow never stops because the secondary cell remains active and continues forwarding packets between source and target gNBs throughout the handover duration.
3Device complexity
If secondary cell is deactivated during handover, then resource management is simplified, but data transmission reliability decreases
Solution Approach 1:
The secondary cell is pre-configured with PDCCH and PUCCH channels before handover occurs. This preliminary setup ensures that when handover is needed, the secondary cell can immediately take over data transmission without resource management complexity, maintaining high reliability.
Solution Approach 2:
The secondary cell serves as an intermediary data transmission path that remains active during handover. It receives data from the source gNB and relays it to the target gNB, ensuring continuous and reliable data transmission without deactivating the secondary cell.
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
Systems, methods, apparatuses, and computer program products for optimized handover to achieve user-plane zero outage, for example with carrier aggregation (CA) or dual connectivity (DC) deployment, are provided.