UE Timer Settings for RLF Categorization in MRO
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Solution Overview
Problem
Current Mobility Robustness Optimization (MRO) systems in mobile radio communications face challenges in accurately categorizing Radio Link Failures (RLFs) that occur without successful handovers, leading to misinterpretation and ineffective network tuning due to the absence of necessary timer settings in RLF reports.
Innovation Solution
Enhancements to RLF report generation, including the introduction of new Information Elements (IEs) such as 'timeRe-EstabFailure', 'connEstabType', and 'ConnectionRe-establishmentTimer', allow the UE to measure and report the time since RRC Connection Re-establishment Complete until RLF, enabling precise identification of failure types even in cases without handover initialization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the timer is only started with handover initialization (RRC-Connection-Reconfiguration message including mobilityControlInfo), then the timer setting is simple and follows the standard procedure, but the MRO cannot correctly categorize RLF failures that occur after cell change without handover initialization
Solution Approach 1:
The patent applies preliminary action by starting the timer not only at handover initialization but also at cell change events. This ensures that the timer is already running and can accurately measure the time elapsed until RLF occurs, even when the failure happens after a cell change without handover initialization. The timer is prepared in advance at all relevant events (handover and cell change) to ensure accurate measurement when needed.
2Measurement precision
If the timer is started at every cell change event including without handover initialization, then the RLF failure categorization becomes accurate, but the system complexity increases
Solution Approach 1:
The patent applies local quality by differentiating the timer starting conditions based on the specific event type. The timer is started at handover initialization events (as before) and also at cell change events without handover initialization (the enhancement). This localized differentiation ensures that the timer is started at the appropriate moment for each type of cell change, providing accurate measurement without unnecessarily complicating the overall system by applying a uniform rule to all events.
3Ease of operation
If no timer is set for cell change without handover initialization, then the system operation is simple, but the MRO cannot perform root cause analysis for such failures
Solution Approach 1:
The patent applies feedback by having the UE measure and report the time elapsed since the last cell change event (with or without handover initialization) until RLF occurs. This feedback mechanism provides the network with crucial information about the timing of failures, enabling MRO to perform accurate root cause analysis. The timer measurement feedback allows the network to distinguish between different failure types and make informed decisions about parameter optimization.
Data Source
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AI summary
The present invention provides apparatuses, methods, computer programs, computer program products and computer-readable media regarding enhanced timer setting for mobility robustness optimization. The present invention comprises detecting, at a user equipment, establishment of a connection to a cell, determining, at the user equipment, whether the connection is established by a connection re-establishment procedure, detecting, at the user equipment, a radio link failure of the connection to the cell, and transmitting, by the user equipment, a message to a base station serving another cell after a further re-establishment or setup of the connection, the message including an indication from which it is derivable whether the radio link failure occurred within a certain time after the establishment of the connection by the connection re-establishment procedure.