RAN-CN Connection Maintenance During 5G to EPC Handover
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Solution Overview
Problem
In Next Generation wireless communication systems, handover processes between different Radio Access Networks (RANs) and Core Networks (CNs) often result in high time consumption and service interruptions due to the complexity of determining whether to perform Radio Access Technology (RAT) or system handovers, especially when transitioning between 5G and Evolved Packet Core (EPC) networks.
Innovation Solution
A method and device that determine, based on UE capability information and service types, whether to maintain the connection between a source RAN and its corresponding CN during handover, thereby avoiding cross-core network-element handovers and reducing service delays by ensuring data is forwarded through the source RAN to the source CN, eliminating the need for CN handover flows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If system handover is performed between 5G CN and EPC, then the UE can access different core networks, but the handover process consumes significant time and causes service interruptions
Solution Approach 1:
The patent segments the handover process into two independent types: RAT handover (keeping the same CN) and system handover (changing CN). By segmenting the decision-making process, the system can choose the faster RAT handover path when appropriate, avoiding the time-consuming CN handover流程 while still maintaining the capability to perform system handover when needed.
Solution Approach 2:
The patent performs preliminary actions by having the source RAN send capability information about the target RAN to the source CN before handover execution. This allows the source CN to pre-determine the handover type and prepare相应的 resources, reducing the actual handover execution time and avoiding service interruptions.
2Adaptability or versatility
If CN handover flow is executed for system handover, then the UE can switch between 5G CN and EPC, but the process is complex and causes service delays
Solution Approach 1:
The patent segments the handover procedure into distinct types (RAT handover and system handover) with different flow complexities. By segmenting the overall handover process, the system can select the simpler RAT handover flow when CN change is not required, thereby reducing handover flow complexity while preserving the capability to execute complex system handover when necessary.
Solution Approach 2:
Instead of always executing the complex system handover flow and then determining whether CN change is needed, the patent inverts the logic by first determining the handover type based on target RAN capability information, and then executing the appropriate handover flow. This inversion avoids unnecessary execution of complex system handover procedures when RAT handover suffices.
3Extent of automation
If the AMF determines whether to perform RAT handover or system handover, then the handover decision can be made centrally, but the AMF lacks sufficient information to make an accurate determination
Solution Approach 1:
The patent performs preliminary information gathering by having the source RAN obtain and forward target RAN capability information to the source CN before the handover decision is made. This preliminary action ensures that the AMF has access to necessary target RAN capability information when making the handover determination, eliminating information loss while maintaining centralized decision-making.
Solution Approach 2:
The patent introduces the source RAN as an intermediary that collects target RAN capability information and forwards it to the source CN (AMF). This intermediary role ensures that the AMF receives accurate and complete information for handover decision-making without requiring direct access to target RAN, thus resolving the information loss problem while maintaining centralized automation.
Data Source
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AI summary
Disclosed in the present invention are a handover method and device, and a computer storage medium. The method comprises: a first access network element, when determining according to first information or a received first message that a terminal is handed over from a first access network to a second access network, ensuring the connection between the first access network and a first core network remains unchanged, the first access network element receiving data of the terminal forward by a second access network element, and sending the data to the first core network element.