UE Handover Control for Mobile Communication RLF Minimization
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Solution Overview
Problem
In mobile communication systems, the concurrent occurrence of handover and Radio Link Failure (RLF) leads to increased handover failure rates and prolonged service interruption times due to the time-consuming Radio Resource Control (RRC) connection re-establishment process.
Innovation Solution
The User Equipment (UE) in the mobile communication system is designed to prioritize handover over RRC connection re-establishment when both events occur simultaneously, by adjusting timers and offsets to minimize service interruption, thereby reducing the need for lengthy RRC connection re-establishment procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RRC connection re-establishment is conducted during handover failure, then connection recovery is achieved, but service interruption time increases
Solution Approach 1:
The system performs preliminary actions by detecting RLF conditions early through monitoring downlink signal quality (RSRP/RSRQ) and uplink signal quality (SRS). When RLF is detected before handover completion, the system proactively initiates handover cancellation and switches to alternative recovery procedures, preventing the time-consuming RRC re-establishment process from being triggered in the first place
Solution Approach 2:
The patent inverts the conventional approach by not immediately initiating RRC connection re-establishment when handover fails. Instead, it first attempts alternative recovery methods such as cell re-selection or switching to a different target cell, only resorting to RRC re-establishment as a last resort. This reversal of the traditional recovery sequence significantly reduces service interruption time
2Device complexity
If handover and RLF are independently operated, then process simplicity is maintained, but handover failure rate increases when they concurrently occur
Solution Approach 1:
The patent merges the previously independent handover and RLF detection processes into a unified coordinated operation. The system combines RLF detection (monitoring downlink/uplink signal quality) with handover execution, allowing the handover process to be dynamically adjusted or cancelled based on real-time RLF conditions. This integration enables the system to detect RLF during handover preparation and respond appropriately, reducing handover failure rates while maintaining operational simplicity
3Reliability
If RRC connection re-establishment is performed during concurrent handover and RLF, then connection is restored, but service interruption time is prolonged
Solution Approach 1:
The system performs preliminary detection of RLF conditions by monitoring downlink signal quality (RSRP/RSRQ) and uplink signal quality (SRS) before handover completion. When RLF is detected early during handover preparation, the system proactively cancels the handover and initiates alternative recovery procedures, preventing the time-consuming RRC re-establishment process from being triggered
Solution Approach 2:
The patent extracts the RLF detection and response mechanism from the standard handover failure recovery process. By separating RLF monitoring (through SRS and downlink signal quality measurement) from the conventional RRC re-establishment flow, the system can identify RLF conditions and apply optimized recovery procedures that bypass the lengthy re-establishment process, achieving faster connection restoration
Data Source
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AI summary
Embodiments of the present disclosure provide a method and an apparatus for efficiently controlling a handover process and a Radio Link Failure (RLF) process in a mobile communication system. According to an embodiment of the present disclosure, an operating method of a User Equipment (UE) in a mobile communication system includes monitoring whether a radio link between a source enhanced NodeB (eNB) and the UE has a preset low channel gain; detecting a target eNB for handover; and when detecting at least one of the radio link having the low channel gain and the target eNB, performing handover within a shorter time than a preset normal time. When the handover and the RLF concurrently occur in the mobile communication system, the embodiments of the present disclosure can minimize the service interruption time by conducting the handover instead of the Radio Resource Control (RRC) connection re-establishment due to the RLF.