Prioritizing PDU Sessions for 5G Network Slice Handover
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Solution Overview
Problem
In 5G wireless communication systems, there is a challenge in maintaining service continuity during handovers across network slices, particularly when user equipment (UE) moves from one cell to another, as not all cells support the same network slices, leading to potential service disruptions and the need to prioritize active PDU sessions.
Innovation Solution
The solution involves an access network node that selects another access network node for transferring PDU sessions based on network slice support, user activity, priority among network slices and sessions, and user consent information, ensuring service continuity by prioritizing the most critical sessions and slices during handovers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE is handed over to a target cell that does not support all active network slices, then handover can be completed, but service continuity is disrupted for PDU sessions on unsupported slices
Solution Approach 1:
The PDU sessions are segmented into two groups: those that can be maintained (supported by target cell) and those that need to be released (not supported by target cell). The access network node selectively transfers only the compatible sessions while releasing the incompatible ones, ensuring service continuity for critical sessions.
Solution Approach 2:
Instead of requiring complete support for all PDU sessions, the solution accepts partial action by maintaining service continuity for the subset of sessions that can be supported by the target cell. This allows handover to proceed with the available capabilities rather than blocking entirely.
2Reliability
If all PDU sessions are maintained during handover, then service continuity is preserved, but handover cannot be completed when target cell lacks support for all slices
Solution Approach 1:
The access network node extracts and identifies the specific PDU sessions that cannot be supported by the target cell. These incompatible sessions are separated from the transfer process, allowing the handover to complete successfully for the remaining sessions while the incompatible ones are appropriately released.
3Reliability
If the access network node selects target cell based on slice support, then service continuity is maintained, but the selection process becomes more complex
Solution Approach 1:
The access network node performs preliminary evaluation of target cell capabilities before finalizing the handover decision. By checking slice support in advance and identifying compatible PDU sessions beforehand, the node avoids complex real-time decision-making during handover execution.
Solution Approach 2:
The system uses feedback from the target cell regarding its supported network slices to inform the handover decision. This feedback mechanism allows the access network node to make informed selections based on actual target cell capabilities rather than assumptions.
4Ease of operation
If the UE is steered to a target cell without considering PDU session priorities, then handover is simplified, but critical services may be disrupted
Solution Approach 1:
The access network node applies different quality criteria to different PDU sessions based on their priority and the target cell's slice support. High-priority sessions receive preferential treatment in the selection process, ensuring that critical services are maintained while less critical sessions may be released if necessary.
Data Source
AI summary
This disclosure addresses the service continuity across network slices for mobile terminals in connected mode. It proposes solutions that allow mobile terminal users to prioritize a service or a type of service that would improve the service continuity across network slices for user preferred services.