Multi-TRP Beam Failure Recovery Priority in Uplink MAC Scheduling
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Solution Overview
Problem
The existing Beam Failure Recovery (BFR) mechanism for multi-TRP systems faces issues with frequent BFR triggers and prioritization conflicts, leading to suboptimal resource allocation and system performance degradation.
Innovation Solution
A method for determining the order of Beam Failure Recovery MAC CEs (BFR MAC CEs) in logical channel prioritization based on the number and association of reference signal resource sets, ensuring that BFR MAC CEs for multi-TRP have lower priority than other MAC CEs, thereby optimizing resource assignment and improving system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If BFR MAC CE for multi-TRP is assigned the same priority as BFR MAC CE for cell, then BFR can be triggered independently for each TRP, but resource allocation becomes suboptimal and system performance degrades due to frequent BFR triggers
Solution Approach 1:
The patent applies local quality by assigning different priority levels to different types of BFR MAC CEs. Specifically, BFR MAC CEs for multi-TRP are assigned a lower priority than BFR MAC CEs for cell-level beam failure. This allows the system to treat different BFR scenarios differently, ensuring that cell-level BFR (which is more critical) receives higher priority resource allocation while multi-TRP BFR can be deferred, thereby resolving the contradiction between independent BFR triggering and system performance.
2Device complexity
If BFR MAC CE for multi-TRP has the same priority as other MAC CEs, then resource assignment is simplified, but urgent logical channel data or MAC CEs are delayed affecting system performance
Solution Approach 1:
The patent implements local quality by creating a differentiated priority structure within the MAC CE hierarchy. Instead of treating all MAC CEs uniformly, the patent specifically assigns lower priority to multi-TRP BFR MAC CEs compared to other MAC CEs including cell-level BFR MAC CEs. This localized differentiation in priority assignment ensures that urgent data and critical control elements receive timely resource allocation while maintaining a manageable resource assignment framework.
3Reliability
If there are multiple reference signal resource sets, then multi-TRP BFR can be detected, but the number of BFR triggers increases excessively
Solution Approach 1:
The patent applies parameter changes by modifying the priority parameter of multi-TRP BFR MAC CEs. By changing the priority level from equal to lower than cell-level BFR MAC CEs, the system effectively controls the trigger frequency behavior. This parameter adjustment allows multiple reference signal resource sets to be monitored for reliable multi-TRP BFR detection while preventing excessive triggering by ensuring that only genuinely critical failures consume uplink resources immediately.
Data Source
AI summary
A method and device in communication node for wireless communications. A communication node receives each reference signal resource set in the first reference signal resource pool, a measurement performed on a first reference signal resource set is used to trigger a first BFR; determines a resource assignment of a first uplink grant according to logical channel prioritization; when the first uplink grant can accommodate a first MAC CE, transmits a first MAC PDU comprising the first MAC CE on resources of the first uplink grant; the first MAC CE is used to indicate the first BFR; a first parameter set is used to determine an order of the first MAC CE in the logical channel prioritization, and the first parameter set comprises a number of the reference signal resource set(s) comprised in the first reference signal resource pool; when the number is 1, the order is a first order.


