Adaptive RLF Timer for NTN Terminals
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Solution Overview
Problem
In non-terrestrial networks (NTN) and Internet of Things (IoT) systems, existing radio link failure (RLF) detection methods struggle to configure appropriate timer durations for RLF detection, leading to delayed link recovery or unnecessary RLF triggers due to varying signal intensities caused by terminal location and satellite cell coverage.
Innovation Solution
The proposed solution involves a method where a terminal determines its location relative to a satellite and configures a timer duration accordingly, using different timer durations or scaling factors based on its location to detect RLF effectively, thereby reducing RRC reestablishment and ensuring timely network recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed timer duration is used for RLF detection, then the detection method is simple, but it causes delayed link recovery or unnecessary RLF triggers due to varying signal intensities at different terminal locations
Solution Approach 1:
The patent applies dynamics by making the timer duration adjustable based on terminal location. Instead of using a fixed timer duration, the system dynamically adapts the timer value according to the terminal's position relative to the satellite cell coverage edge, allowing optimal RLF detection timing for each location scenario
Solution Approach 2:
The patent applies local quality by implementing location-specific timer configurations. Different timer durations are assigned to different terminal locations (e.g., near coverage edge vs. center), ensuring that each local scenario uses the most appropriate detection parameters for its specific signal conditions
2Reliability
If a longer timer duration is used for RLF detection, then false RLF triggers are reduced, but link recovery is delayed when signal intensity is low due to terminal location
Solution Approach 1:
The patent applies parameter changes by modifying the timer duration parameter based on terminal location. The system changes this critical timing parameter to match the signal conditions at different locations, using longer durations where signals are weaker and more stable recovery is needed, and shorter durations where quick recovery is prioritized
3Loss of time
If a shorter timer duration is used for RLF detection, then link recovery is faster, but unnecessary RLF triggers increase due to signal fluctuations at coverage edge
Solution Approach 1:
The patent applies parameter changes by adjusting the timer duration parameter according to terminal location. When terminals are near the coverage edge where signal fluctuations occur, the system increases the timer duration to filter out false triggers, while maintaining shorter durations in stable coverage areas for faster recovery
Data Source
AI summary
An RLF detection method is executed by a terminal and includes: determining configuration information related to RLF detection, and determining location information of the terminal; and starting a first timer based on the configuration information and/or the location information of the terminal, the first timer being used for the RLF detection.