Radio Link Monitoring with Sub-band Interference Measurements

The patent introduces downlink reference signals (DL RS) that are transmitted periodically or semi-persistently before actual data transmission occurs. These reference signals serve as preliminary observations that allow the UE to monitor radio link quality in advance, ensuring reliable detection even when data transmission is sporadic. The network configures DL RS resources specifically for RLM purposes, independent of data scheduling decisions.

The system enables the UE to autonomously perform radio link monitoring using configured reference signals without requiring continuous data transmission. The UE self-services the monitoring function by measuring DL RS quality metrics (such as RSRP, RSRQ, or SINR) and independently determining radio link status, freeing the system from needing persistent data channels for monitoring purposes.

Instead of continuous monitoring, the patent implements periodic monitoring using downlink reference signals that are transmitted at specific intervals. The network configures the periodicity of DL RS transmission, and the UE performs measurements only at these scheduled times. This periodic approach maintains adequate monitoring reliability while significantly reducing the UE's energy consumption compared to continuous observation of downlink control channels.

The system uses partial action by monitoring only specific reference signal resources rather than the entire downlink control channel spectrum. The UE performs measurements on a subset of configured DL RS resources that are sufficient for radio link assessment, avoiding the excessive energy consumption that would result from monitoring all downlink control channel elements continuously.

The patent divides the downlink bandwidth into multiple sub-bands and configures separate DL RS resources for each sub-band. The UE performs interference measurements independently on each sub-band, allowing precise identification of frequency-specific interference conditions. This segmentation enables the system to detect interference in specific frequency regions without requiring complex full-bandwidth analysis, as each sub-band can be monitored with simpler, dedicated measurement processes.

The system applies local quality by configuring DL RS resources with specific properties tailored to each sub-band's interference characteristics. Different sub-bands may have different reference signal configurations optimized for their local conditions, allowing the UE to perform measurements with appropriate precision for each region without requiring a single complex monitoring mechanism for the entire bandwidth.