Power Headroom Reporting for Multi-TRP Uplink Repetitions
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Solution Overview
Problem
Conventional PHR reporting techniques do not specify how to determine and report multiple PHR values when PUSCH repetitions are configured for multiple TRPs, nor do they define which PUSCH transmissions should be used as the basis for a reported PHR value or whether actual or virtual PHR values should be reported, and they fail to organize multiple PHR values within a single PHR report.
Innovation Solution
The techniques enable UEs to support different rules for reporting multiple PHR values for a single component carrier when scheduled for PUSCH repetitions using multiple beams, allowing UEs to determine PHR values for each set of linked PUSCH transmissions according to a pre-configured PHR reporting configuration and report them via a single PHR report, with indicators for the order and type of PHR values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple PHR values are reported for different sets of linked PUSCH transmissions, then the accuracy and coordination of power control is improved, but the signaling overhead and report complexity increase
Solution Approach 1:
The patent segments the PHR reporting by introducing a PHR per TRP indicator that divides the report into separate PHR values for different transmission reception points. Each PHR value corresponds to a specific TRP and its associated beam set, allowing the network to receive targeted power headroom information for each TRP without requiring a completely separate reporting mechanism for each.
Solution Approach 2:
The patent adds a new dimension to PHR reporting by introducing the PHR per TRP indicator as an additional field in the PHR MAC CE. This indicator enables the report to convey multi-dimensional information (multiple PHR values for different TRPs) within a single standardized reporting structure, rather than requiring multiple separate reports.
2Reliability
If separate PHR values are reported for each uplink beam, then the network coordination is improved, but the signaling overhead increases
Solution Approach 1:
The patent merges multiple PHR values for different beams and TRPs into a single PHR MAC CE report by introducing a PHR per TRP indicator. This allows the network to receive comprehensive power headroom information for multiple beams and TRPs in one consolidated report, reducing the number of separate signaling messages required while maintaining complete information.
3Ease of manufacture
If conventional PHR reporting techniques are used without specific rules for multiple TRPs, then the implementation is simpler, but the reporting is incomplete and ambiguous
Solution Approach 1:
The patent establishes preliminary rules and configurations for PHR reporting in multi-TRP scenarios through RRC signaling. The network configures parameters such as phr-PeriodicTimer, phr-ProhibitTimer, and powerHeadroomReportConfig before PHR reporting begins, providing clear guidelines for UE behavior in multi-TRP situations. This preliminary configuration prevents ambiguity during actual reporting while maintaining implementation simplicity.
Data Source
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AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may be configured to receive control signaling scheduling multiple uplink transmission repetitions including first and second sets of repetitions associated with first and second sounding reference signal (SRS) resource sets, respectively. The UE may determine first and second power headroom (PHR) values for the respective sets of repetitions, where at least the second PHR value is determined in accordance with a first rule as either an actual value based on a transmission power of one of the uplink transmission repetitions or a virtual value based on default transmission power settings, the first rule pertaining to PHR determination for multiple sets of repetitions corresponding to multiple SRS resource sets. The UE may generate a PHR report that includes the first PHR value, the second PHR value, or both, and may transmit the PHR report to the base station.