Multi-TRP Beam Measurement Scheduling Under Directivity Limits
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Solution Overview
Problem
In multi-TRP deployments, network entities schedule UE operations assuming full-array directivity gain, despite UE using sub-arrays for TRP-specific reference signal tracking, leading to increased communication failures and latency.
Innovation Solution
UEs employ a signaling-based mechanism to request scheduling restrictions based on directional beam usage, directivity gain thresholds, and phased array association during multi-TRP beam management, enabling or disabling restrictions to optimize control and data channel transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If network entities schedule UE operations assuming full-array directivity gain, then scheduling simplicity is maintained, but communication reliability deteriorates due to increased communication failures
Solution Approach 1:
The patent implements dynamic scheduling restrictions that adapt to the UE's actual beam usage patterns. The network entity receives indications from the UE about whether different directional receive beams are used for group-based reference signal measurements versus control/data channel receptions, and accordingly dynamically applies scheduling restrictions only when needed, rather than using static assumptions about full-array directivity gain.
Solution Approach 2:
The UE provides feedback to the network entity regarding its beam usage behavior - specifically whether it uses different directional receive beams for measurements than for control/data channel receptions. This feedback enables the network entity to adjust scheduling decisions accordingly, improving reliability by aligning scheduling with actual UE operations while maintaining simplicity through automated feedback-driven adjustments.
2Reliability
If network entities apply scheduling restrictions during group-based measurements, then communication reliability improves, but productivity deteriorates due to increased latency
Solution Approach 1:
The scheduling restriction mechanism is made dynamic rather than static. The network entity applies scheduling restrictions only during specific time periods when the UE actually uses different directional receive beams for group-based measurements, and releases restrictions when the UE uses the same beams for both measurements and control/data channel receptions. This dynamic approach ensures reliability when needed while minimizing latency impact on productivity.
3Adaptability or versatility
If UEs use sub-arrays for TRP-specific reference signal tracking, then adaptability to multi-TRP deployments improves, but directivity gain deteriorates leading to increased communication failures
Solution Approach 1:
The patent acknowledges and utilizes the segmentation of the UE's phased array into sub-arrays for tracking reference signals from different TRPs in multi-TRP deployments. Rather than treating the array as a unified full-array system, the invention accommodates the segmented sub-array structure and its associated lower directivity gain by implementing scheduling restrictions that protect control and data channel transmissions during measurement periods.
Solution Approach 2:
The network entity applies scheduling restrictions beforehand during time periods when the UE performs group-based measurements using sub-arrays. These restrictions cushion or protect against potential communication failures by preventing scheduling of control and data channels during periods when the UE's directivity gain is reduced due to sub-array usage, thereby compensating for the adaptability-enabled multi-TRP operation.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. In some aspects, a user equipment (UE) may receive an indication of a set of channel measurement resources (CMRs) that are configured for a group-based reference signal measurement for multiple transmission and reception points (TRPs). The UE may identify or determine whether a set of one or more directional beams used by the UE to measure reference signal transmissions from each of the multiple TRPs satisfy a threshold directivity gain. The UE may transmit a request to enable a scheduling restriction at the UE for a time period associated with the group-based reference signal measurement if the set of directional beams fail to satisfy the threshold directivity gain and may transmit a request to disable the scheduling restriction if the set of directional beams satisfy the threshold directivity gain.