UE Spatial Filter Configuration for SCell Beam Failure Recovery
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Solution Overview
Problem
Current beam failure recovery procedures in 5G and NR wireless communication systems do not effectively differentiate between primary and secondary cells, leading to inefficiencies in recovering from beam failures, especially when the secondary cell lacks an uplink and uplink control signaling is sent on the primary cell, resulting in increased latency and power consumption due to antenna panel activation delays.
Innovation Solution
The method involves detecting SCell beam failure at the MAC layer, requesting and selecting candidate beam measurements, and generating a MAC CE to indicate new candidate resources, allowing the UE to set the spatial Rx filter based on reported CSI-RS and SSB indexes, and using PCell or SCell for TCI state configuration to minimize panel activation delays and optimize beam recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the UE uses current beam failure recovery procedures that do not differentiate between primary and secondary cells, then the recovery procedure is simple and unified, but the latency increases and power consumption increases due to antenna panel activation delays
Solution Approach 1:
The patent segments the beam failure recovery procedure into cell-specific operations. The UE independently recovers SCell beams by selecting spatial Rx filters based on reported CSI-RS and SSB indexes for each SCell, rather than using a unified recovery procedure. This segmentation allows parallel recovery operations and eliminates unnecessary antenna panel activation delays associated with PCell-based recovery, thereby reducing overall recovery latency while maintaining procedural simplicity through standardized cell-specific operations.
2Device complexity
If the UE sends uplink control signaling on the primary cell for SCell beam failure, then the signaling path is unified and simple, but the power consumption increases due to antenna panel activation delays
Solution Approach 1:
The patent applies local quality by allowing the UE to use the SCell's own downlink measurements (CSI-RS and SSB) to determine spatial Rx filters specifically for that SCell's beam recovery. This cell-local approach enables the UE to maintain appropriate receiver configurations for each cell independently, avoiding the need to activate antenna panels for PCell-based signaling when SCell-specific recovery is sufficient, thereby reducing power consumption while maintaining manageable signaling complexity through standardized MAC CE reporting.
3Extent of automation
If the UE recovers SCell beams using PCell-based procedures, then the recovery process is centralized and controlled, but the network reliability decreases due to increased latency and power consumption
Solution Approach 1:
The patent enables self-service by allowing the UE to autonomously recover SCell beams using locally available downlink measurements (CSI-RS and SSB) and cell-specific spatial filter selection. The UE independently determines the spatial Rx filter for each SCell based on reported measurements without requiring centralized PCell-based coordination. This self-service approach reduces latency and power consumption, thereby improving network reliability while maintaining automated operation through standardized MAC CE reporting and cell-specific recovery procedures.
Data Source
AI summary
Systems, methods, apparatuses, and computer program products for beam failure recovery are provided. Beam failure recovery may include detecting and/or declaring, by a user equipment, UE, secondary cell, Scell, beam failure at MAC layer and e.g. determining and/or selecting CSI-RS and/or SSB indexes for transmission to a network node.