Handover Resume Message Reduces Interruption Time
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Solution Overview
Problem
Current handover processes in LTE and NR networks result in significant data packet interruption times, which are not tolerable for ultra-reliable low latency services and industrial applications, and existing solutions like make-before-break (MBB) and RACH-less handover have limitations and uncertainties, especially in larger cells without co-located antennas.
Innovation Solution
The implementation of a handover technique using two transceivers (TRX) that continues data transmission after a handover command is sent, with a source base station sending a resume message to initiate a RACH-less handover procedure, allowing seamless data forwarding to a target cell without interruption, reducing the overall handover time to approximately 4 milliseconds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional handover procedures are used in LTE and NR networks, then the handover process is completed, but significant data packet interruption times occur which are not tolerable for ultra-reliable low latency services
Solution Approach 1:
The source base station performs preliminary actions by sending a handover resume message to the target base station before the actual handover execution. This advance notification allows the target base station to prepare resources and configuration in advance, enabling seamless data forwarding and reducing interruption time to approximately 4 milliseconds.
Solution Approach 2:
The handover procedure maintains continuity of data transmission by establishing a data forwarding path from the source base station to the target base station during the handover process. The source base station continues to send data packets to the target base station, which forwards them to the user equipment, ensuring uninterrupted data flow and maintaining ultra-reliable low latency service quality.
2Speed
If make-before-break (MBB) and RACH-less handover solutions are implemented, then handover speed is improved, but limitations and uncertainties remain especially in larger cells without co-located antennas
Solution Approach 1:
The handover resume message mechanism provides a universal solution that works across different cell scenarios including large cells, small cells, co-located antennas, and non-co-located antennas. The target base station can handle various handover types (MBB, RACH-less, traditional) through the same resume message framework, making the solution universally applicable without scenario-specific limitations.
3Loss of time
If handover procedures are simplified to reduce interruption time, then handover speed improves, but protocol stack and security key complexity may increase
Solution Approach 1:
The handover resume message extracts and separates the essential handover information from the complex protocol stack procedures. By conveying critical handover parameters, security key information, and data forwarding instructions in a dedicated resume message, the solution simplifies the overall protocol processing while maintaining security and reducing interruption time to approximately 4 milliseconds.
Data Source
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AI summary
A technique of performing a HO includes the source BS sending a HO resume message to the UE at the conclusion of a RACH access procedure that occurs in response to a HO command while a second TRX of the UE continues to exchange data packets with the source BS as if no HO command were issued. By continuing to exchange data with the source BS as if there were no HO command until the HO resume message reintroduces a RACH-less HO procedure, the interruption may be reduced to about 4 msec. At any point in time the UE handles only one protocol stack and only one security, which avoids the complexity of the advanced prior art methods.