Beam-Specific Power Control for Accurate NR Power Headroom Reporting

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Solution Overview

Problem

Existing 3GPP NR systems lack defined methods for beam-specific power control, which is crucial for efficient communication in cellular networks, especially in high-frequency mmWave communications.

Innovation Solution

Implement beam-specific power control (PC) by configuring PC parameter sets on a beam-specific basis, using closed-loop power control and power headroom reporting (PHR) calculations based on path loss estimates and reciprocity-based beamforming, with explicit or implicit signaling for UL Tx beam determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If beam-specific power control is implemented in 3GPP NR systems, then power efficiency and communication quality are improved, but system complexity increases due to undefined details and lack of standardized methods

Engineering Contradiction:
Improvepower efficiencyVSAvoidsystem complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent segments power control into multiple independent processes, each associated with specific beam pairs. Multiple PC processes are configured with different parameter sets (path loss reference signals, closed-loop indices, etc.) to handle different beam-specific conditions independently, allowing granular power optimization without requiring complete redesign of the power control system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by configuring power control parameters specifically for each beam pair link. Different beams can have different path loss estimates, closed-loop correction factors, and power control adjustments tailored to their specific propagation conditions, rather than applying a uniform power control approach across all beams.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If beam-specific power control with multiple PC processes is configured, then power headroom reporting accuracy is improved, but calculation complexity and processing overhead increase

Engineering Contradiction:
Improvepower headroom reporting accuracyVSAvoidcalculation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides power headroom calculation into separate calculations for each beam pair link when multiple PC processes are configured. Instead of one complex aggregate calculation, the system performs multiple simpler calculations for individual beams, each using its own PC parameters, making the overall process more manageable and accurate.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements partial action by calculating power headroom for only the active beam pairs that are currently being used for communication, rather than calculating for all possible beam combinations. This reduces unnecessary computational overhead while maintaining accuracy for the relevant beams.

Inventive Principle:
Principle #16Partial or excessive action

3Power

If path loss estimates are calculated for each beam pair, then transmission power optimization is improved, but measurement and calculation overhead increases

Engineering Contradiction:
Improvetransmission power optimizationVSAvoidmeasurement overhead
Core Design Contradiction:
PowerVSDifficulty of detecting and measuring

Solution Approach 1:

The patent uses path loss reference signals as intermediaries to estimate path loss for each beam pair. Instead of directly measuring complex propagation conditions, the system uses these reference signals as a simplified proxy that correlates with actual path loss, reducing measurement complexity while maintaining optimization accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs self-service by having the UE autonomously calculate path loss estimates for each beam pair using the configured reference signals and closed-loop power control processes, without requiring extensive network assistance or complex coordinated measurements between multiple nodes.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4258756B1Beam-specific power control
Publication Date: 2026.03.04 APPLE INC
  • EP4258756B1 patent drawingFigure 1(a)~1(b)
  • EP4258756B1 patent drawingFigure 2
  • EP4258756B1 patent drawingFigure 3

AI summary

There is provided a base station (BS) comprising: a memory; and a processor communicatively coupled to the memory, configured to: transmit configuration information to a user equipment (UE) to configure a beam-specific power control (PC) process with a PC parameter set that includes a path loss scaling factor, a command to perform a closed-loop PC process, or a path loss change parameter to be used to trigger a power headroom report (PHR); receive the PHR comprising a power headroom value based on the PC parameter set and the beam-specific PC process, wherein the PC parameter set further comprises: a beam index, b, a serving cell index, c, a maximum UE transmission power of the beam b in the serving cell c, a reference receive power of a physical uplink shared channel (PUSCH), a configured scaling factor of path loss in the beam b of the serving cell c, a path loss estimate of the beam b in the serving cell c, and a command to perform a closed-loop PC process at a subframe t for the beam b in the serving cell c; determine a downlink transmit beam based at least on the PHR; and signal an indication of the downlink transmit beam to the UE.