Handover Pre-Preparation for Seamless Wireless Service Continuity
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Solution Overview
Problem
In LTE wireless communication systems, handover procedures are disrupted by backhaul link failures and home base station failures, leading to service disruptions and UE transitions to RRC_IDLE state, as existing systems do not prepare for handovers in advance and lack mechanisms to handle failures effectively.
Innovation Solution
A method and device for initiating handover pre-preparation by receiving a pre-prepared handover command from a source base station, which includes context of a target base station, allowing the mobile device to keep this context for a period, enabling seamless handover when the source base station becomes unreliable, using a specific indicator to distinguish pre-preparation from normal handover procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If handover preparation is performed in advance with pre-prepared handover commands, then service continuity is improved during backhaul link failures, but device complexity and signaling overhead increase
Solution Approach 1:
The patent implements preliminary handover preparation by having the source base station send a pre-prepared handover command to the UE before actual handover execution is needed. This command includes target base station context information in advance, so that when backhaul link failures occur, the UE can immediately execute the pre-prepared handover without waiting for new preparation procedures, thus maintaining service continuity while managing complexity through advance preparation.
Solution Approach 2:
The patent uses copying by creating a duplicate of the handover command and target base station context information and storing it in the UE's memory. This copied information is kept ready for potential future use, allowing the UE to quickly reference and execute the handover procedure without re-establishing connections or re-negotiating parameters, thereby improving reliability during failures.
2Speed
If the UE keeps target base station context for an extended period, then handover execution speed is improved during failures, but memory resources and information management complexity increase
Solution Approach 1:
The patent applies dynamics by implementing a timer-based mechanism that automatically manages the validity period of stored target base station context information. The UE keeps the context information only for a predetermined time period, after which it is automatically cleared. This dynamic approach allows the UE to maintain information long enough to enable fast handover execution during failures, while preventing indefinite storage that would consume memory resources and complicate information management.
3Loss of time
If pre-prepared handover commands are sent before actual handover need, then service disruption time is reduced during backhaul failures, but signaling overhead and network resource consumption increase
Solution Approach 1:
The patent implements self-service by enabling the UE to autonomously detect backhaul link failures and automatically execute the pre-prepared handover command without requiring additional network signaling or intervention. The UE uses its own stored context information and local decision-making capabilities to perform the handover, thereby reducing service disruption time while minimizing additional signaling overhead to the network.
Data Source
AI summary
A method of initiating handover pre-preparation for a mobile device in a wireless communication system is disclosed. The method comprises the steps of receiving a pre-prepared handover command from a source base station, wherein the pre-prepared handover command includes context of a target base station, whereby the mobile device does not perform a handover procedure based on the pre-prepared handover command and keeping the context for a period of time.