Bearer Switching in Small Cells Without Data Loss
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Solution Overview
Problem
In the context of carrier aggregation between different base stations, existing path switching processes fail to correctly notify the core network of bearer switches, leading to data loss and service discontinuity due to improper bearer release or assignment, especially in scenarios involving macro and small cells.
Innovation Solution
A method where the master base station sends a path switching request message to the MME, including information on unchanged bearers, ensuring the MME reserves these bearers and maintains the existing SGW, MME UE S1AP ID, and security context, thereby preventing data loss and maintaining service continuity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the existing path switching process is used to notify the core network of bearer switches, then the notification process is simple, but data loss occurs and service continuity is affected due to incorrect bearer management
Solution Approach 1:
The patent segments the bearer list into two distinct parts: a first list indicating bearers to be switched and a second list indicating bearers to be kept unchanged. This segmentation resolves the contradiction by allowing the MME to precisely control which bearers are switched and which are maintained, preventing both data loss from incorrect release and the complexity of managing multiple separate notification processes.
Solution Approach 2:
The patent applies preliminary action by having the source eNB explicitly indicate in advance which bearers should be kept unchanged before the handover is completed. This allows the MME to pre-configure the bearer management state, ensuring that bearers marked as unchanged are preserved and preventing data loss that would otherwise occur with the existing path switching process.
2Device complexity
If the MME assigns a new MME UE S1AP ID when receiving the path switching message, then the S1 interface management is simplified, but duplicate logic connections are created causing errors
Solution Approach 1:
The patent applies dynamics by making the MME UE S1AP ID assignment conditional rather than fixed. When the handover involves a change in S1 interface, the MME assigns a new ID; when the S1 interface remains the same, the existing ID is reused. This dynamic approach resolves the contradiction by adapting the ID management to the actual handover scenario, preventing duplicate connections while maintaining simplified management through automatic decision-making.
3Reliability
If the MME provides a new security context to the base station, then security is enhanced, but security context mismatches occur between UE and network side
Solution Approach 1:
The patent applies feedback by having the source eNB provide information about the handover scenario to the MME, which then uses this feedback to decide whether to update the security context. When the handover is within the same eNB or security context should be maintained, the MME reuses the existing context; when security update is needed, it provides a new context. This feedback mechanism resolves the contradiction by ensuring security context consistency while maintaining security through conditional updates.
Data Source
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AI summary
The present application discloses a switch supporting method comprising: an eNB sends a path switching request message to an MME to notify the MME of information on a bearer remaining unchanged; the MME reserves the bearer remaining unchanged and does not trigger a deactivation process for the bearer remaining unchanged; the MME sends a modify bearer request message to an SGW. With the present application, data loss can be avoided and service continuity is ensured when a UE moves in a small cell scenario.