Two-Step Handover for 5G to 4G Network Transition
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Solution Overview
Problem
In Next Generation (NG) wireless communication systems, the existing handover processes between 5G and 4G networks are inefficient, leading to delays and potential service interruptions due to the complexity of cross-system handovers, especially when user equipment (UE) moves rapidly, causing handover commands to be transmitted late and resulting in failures.
Innovation Solution
A method and device for handover that involves a two-step process: first, the UE is handed over from one Radio Access Network (RAN) to another while maintaining a connection with the original core network, and then the core network is handed over, allowing data to be transmitted between the new RAN and the new core network, thereby reducing delays and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cross-system handover process is executed between 5G CN and EPC, then handover between different core networks is achieved, but the process becomes complex with too many steps for preparation of target network links and resources
Solution Approach 1:
The patent segments the handover process into two distinct phases: first, RAN handover (from source RAN to target RAN) is completed while maintaining connection to the original core network; second, core network handover (from first core network to second core network) is executed separately. This segmentation simplifies the overall complex cross-system handover process by breaking it into manageable steps with clear boundaries.
Solution Approach 2:
The patent performs preliminary RAN handover before executing the core network handover. By completing the RAN handover first and maintaining the UE's connection to the original core network during this phase, the system prepares the target RAN resources in advance while avoiding the complexity of simultaneous core network and RAN handover execution.
2Adaptability or versatility
If traditional cross-system handover process is used, then handover between 5G and 4G networks is possible, but time consumption is high leading to service interruption and long delay
Solution Approach 1:
The patent divides the handover process into sequential segments: RAN handover followed by core network handover. This segmentation allows the time-consuming core network handover preparation to occur after the RAN handover is already complete, reducing the overall handover time and minimizing service interruption.
Solution Approach 2:
The patent executes preliminary RAN handover while maintaining the existing core network connection, preparing target resources in advance. This preliminary action reduces the critical path time for the overall handover process, as the core network handover can then proceed without waiting for RAN handover completion.
3Speed
If handover command is transmitted in traditional process, then handover instruction is delivered to UE, but when UE moves too fast the command is transmitted too late resulting in handover failure
Solution Approach 1:
The patent triggers and executes RAN handover in advance based on measurement reports from the UE, before the UE moves out of the source RAN's coverage area. By performing this preliminary RAN handover while the UE is still within range, the system ensures reliable connection establishment even when the UE is moving at high speeds.
Solution Approach 2:
The patent separates the handover trigger and execution into distinct phases: RAN handover is triggered and completed first based on real-time measurement reports, ensuring reliability at high speeds; the core network handover is then executed separately, allowing the system to adapt to the UE's movement status without compromising the critical RAN connection.
Data Source
AI summary
A handover method and apparatus, and a computer storage medium are provided. The method comprises: a first access network element sending a first handover request message to a second access network element so as to trigger the handover of a terminal from a first access network to a second access network, and keeping a connection between the first access network and a first core network unchanged, wherein data of the terminal is forwarded by the second access network and is transmitted between the first access network and the first core network; and the first access network element sending a second handover request message to a first core network element to trigger the handover from the first core network to a second core network, wherein the data of the terminal is transmitted between the second access network and the second core network.