User Equipment Power Headroom Reporting for Flexible NR Power Control

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Solution Overview

Problem

In future radio communication systems like NR, the range that can be taken by the Power Headroom Report (PHR) values is assumed to be large compared to LTE, leading to inadequate transmit power control, which deteriorates communication throughput and quality.

Innovation Solution

A user terminal that includes a control section and transmitting section, capable of dynamically adjusting the step size and range of Power Headroom Report (PHR) values based on specific bits, band in use, UE capability, maximum transmit power, and explicit notifications, to ensure accurate power control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the PHR reporting range is kept the same as LTE, then the device complexity is reduced, but the measurement precision deteriorates because the fixed range cannot adequately cover the larger power values in future radio communication systems

Engineering Contradiction:
ImprovePHR reporting precisionVSAvoidPHR reporting mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the PHR reporting range configurable rather than fixed. The base station can dynamically adjust the reporting range based on the actual power headroom values observed in the network, allowing the system to adapt to different power scales in future radio communication systems while maintaining manageable device complexity through centralized control

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of PHR reporting range from a fixed value to a configurable parameter. By allowing the base station to set different reporting ranges according to network conditions and power class requirements, the system achieves better measurement precision without permanently increasing device complexity

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the PHR reporting range is expanded to cover larger power values, then the adaptability improves for future radio communication systems, but the manufacturing precision deteriorates because the index-to-value mapping becomes less accurate

Engineering Contradiction:
ImprovePHR reporting adaptabilityVSAvoidindex-to-PH value mapping precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent makes the PHR reporting range dynamic and configurable by the base station. When future radio communication systems require larger power value coverage, the base station can adjust the reporting range parameters to match the new requirements, maintaining adaptability while preserving mapping precision through appropriate parameter selection

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent allows flexible parameter configuration for PHR reporting. By changing the reporting range parameters according to the specific power class and system requirements, the patent achieves both adaptability for different scenarios and precision in the index-to-value mapping for each configured range

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the PHR reporting range is increased to support larger power values, then the reliability of transmit power control improves, but the loss of information increases because more bits are required to represent the expanded range

Engineering Contradiction:
Improvetransmit power control reliabilityVSAvoidPHR information bits
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent optimizes the PHR reporting parameters to match actual network conditions. By configuring appropriate reporting ranges based on the power class and system requirements, the patent achieves reliable transmit power control while minimizing information loss by using only the necessary number of bits for each specific range

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3751913B1User equipment
Publication Date: 2025.07.09 NTT DOCOMO INC
  • EP3751913B1 patent drawingFigure 1
  • EP3751913B1 patent drawingFigure 2
  • EP3751913B1 patent drawingFigure 3A~3B

AI summary

A user terminal according to one aspect of the present disclosure includes: a control section that determines a step size of a value of a Power Headroom (PH) per increase of an index related to the PH or a range of a value of the PH associated with the index based on a given condition; and a transmitting section that transmits a Power Headroom Report (PHR) including the index. According to one aspect of the present disclosure, it is possible to report an appropriate PH in future radio communication systems, too.