Radio Link Failure Detection in DRX Mode Transitions
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Solution Overview
Problem
Current LTE systems lack a clear radio link failure (RLF) detection mechanism for user equipment (UE) operating in Discontinuous Reception (DRX) mode, making it difficult to efficiently detect and recover from RLF.
Innovation Solution
The proposed method adjusts the radio link monitoring period in both non-DRX and DRX modes by defining specific durations for monitoring and averaging the radio channel status, allowing the UE to efficiently detect RLF by transitioning between modes and reporting synchronization status to higher layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If UE operates in DRX mode to save energy, then energy consumption is reduced, but RLF detection capability deteriorates due to discontinuous monitoring
Solution Approach 1:
The patent applies dynamics by making the RLF detection period adjustable based on the operational mode. The detection period is extended when transitioning from non-DRX to DRX mode, allowing the system to adapt the monitoring duration dynamically to match the energy-saving requirements of DRX operation while maintaining adequate RLF detection capability.
Solution Approach 2:
The patent changes the parameter of detection period duration based on the operational mode. By defining different detection periods for non-DRX and DRX modes, and introducing transition periods with specific durations (first period of M DRX cycles, second period of N DRX cycles), the system adjusts monitoring parameters to balance energy savings with detection reliability.
2Adaptability or versatility
If UE transitions between DRX and non-DRX modes, then operational flexibility is improved, but detection accuracy deteriorates due to mode transition effects
Solution Approach 1:
The patent applies preliminary action by defining transition periods before and after mode changes. The first period (M DRX cycles) and second period (N DRX cycles) are designated as transition periods where specific detection rules apply. This preliminary preparation ensures that detection accuracy is maintained during the vulnerable transition phases when switching between operational modes.
Solution Approach 2:
The system dynamically adjusts detection parameters based on the current operational mode and transition state. By introducing different detection period definitions for non-DRX mode, DRX mode, and transition periods, the system maintains detection accuracy while allowing flexible mode transitions.
3Reliability
If detection period is extended to improve RLF detection, then detection reliability is improved, but time consumption increases
Solution Approach 1:
The patent applies local quality by making the detection period duration location-specific in time. Different detection periods are applied to different time intervals: a first period of M DRX cycles after transitioning from non-DRX mode, a second period of N DRX cycles after transitioning to DRX mode, and standard periods for stable operation. This localized approach ensures enhanced detection reliability during critical transition periods without excessively extending the detection period during stable operation.
Data Source
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AI summary
A radio link failure detection method of a user equipment transitioning between a Discontinuous Reception (DRX) mode and non-DRX mode cyclically in a wireless communication system includes transitioning between a Discontinuous Reception (DRX) mode and a non-DRX mode in a wireless communication system. The method also includes adjusting, when a mode transition occurs, a size of a monitoring window for a transitioned operation mode; reporting a radio channel condition acquired by monitoring and averaging the channel condition within the monitoring window; and repeating adjustment of the monitoring window size and report of the radio channel condition while moving the monitoring window as time progress.