Radio Link Failure Determination with Interference Coordination
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Solution Overview
Problem
Existing criteria for analyzing radio link failure conditions in wireless communication networks do not adequately address interference coordination between cells, leading to erroneous declarations of radio link failure due to high interference, even when a user equipment (UE) can still access resources yielded by an interfering cell.
Innovation Solution
A method and system for determining radio link failure that accounts for cooperative resource coordination by detecting interference from an interfering base station, receiving messages identifying yielded resources, and determining signal quality to declare radio link failure only when it meets a predetermined threshold, using an interference coordination and cancellation mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing radio link failure criteria are used to detect interference, then interference detection is simple, but erroneous RLF declarations occur when UE measures non-yielded resources with high interference
Solution Approach 1:
The patent segments the interference coordination mechanism by dividing resources into yielded and non-yielded resources. The UE separately measures signal quality on yielded resources (where interference is coordinated) and compares it against thresholds, rather than averaging over all resources. This segmentation allows accurate RLF determination by focusing only on resources where the UE can actually access service.
Solution Approach 2:
The patent introduces an intermediary mechanism where the serving base station provides information about yielded resources from interfering cells to the UE. This intermediary information allows the UE to distinguish between yielded and non-yielded resources, enabling precise measurement and avoiding erroneous RLF declarations caused by measuring high-interference non-yielded resources.
2Reliability
If UE measures all available resources including non-yielded resources, then measurement coverage is complete, but signal quality varies considerably leading to incorrect RLF decisions
Solution Approach 1:
The patent applies local quality by having the UE measure signal quality specifically on yielded resources rather than uniformly across all resources. Different resource types (yielded vs. non-yielded) are treated differently in the measurement process. The UE determines signal quality metrics such as RSRP or SINR specifically on the yielded resources where interference has been coordinated, ensuring measurements reflect actual service conditions.
3Speed
If UE declares RLF upon detecting high interference, then interference response is prompt, but communication is unnecessarily interrupted when yielded resources are available
Solution Approach 1:
The patent implements preliminary action by having the network pre-configure the UE with information about yielded resources before RLF detection is needed. The serving base station provides yielded resource information to the UE in advance through RRC signaling or system information. When interference occurs, the UE can immediately measure on the pre-identified yielded resources and make rapid RLF decisions without needing to discover which resources are yielded, thus maintaining both speed and reliability.
Data Source
AI summary
Existing criteria for analyzing radio link failure conditions may not satisfactorily address the conditions between cells that support cooperative resource coordination. Generally, when the UE declares radio link failure, the UE discontinues communication with a serving base station and searches for a new base station. When the UE lies in a region with severe interference, where the interference is coordinated between base stations by the interfering cell yielding part of its resources, the UE measurements for determining radio link failure (RLF) may vary considerably, depending on whether the measured resources were yielded by the interfering cell. When the UE measures resources which were not yielded by the interfering cell, the UE can erroneously declare RLF (e.g., due to high interference), although the UE can still access the serving cell using resources yielded by the interfering cell. Accordingly, disclosed are aspects for determining RLF based by accounting for cooperative resource coordination employing yielded resources.