PMPR MAC Control Element Timing for Accurate UE Power Headroom

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Solution Overview

Problem

In next-generation mobile communication systems like NR, there is a challenge in properly calculating UE maximum output power (PCMAX) due to unclear application of power-management maximum power reduction (PMPR) using medium access control-control elements (MAC CEs), which can lead to improper compliance with maximum permitted exposure (MPE) regulations and potential system performance deterioration.

Innovation Solution

A terminal and method that includes transmitting a MAC CE with PMPR and a first value indicating its application timing, allowing for clear application of PMPR in controlling uplink signals to ensure compliance with MPE regulations and improve system performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If PMPR is applied to calculate PCMAX without clear application timing, then power management is simplified, but calculation accuracy of PCMAX deteriorates leading to MPE compliance issues

Engineering Contradiction:

Improvepower management complexityVSAvoidPCMAX calculation accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by indicating the application timing of PMPR in advance within the MAC CE message. This allows the UE to know beforehand when the PMPR value should be applied to PCMAX calculation, ensuring both compliance with MPE regulations and accurate power management without adding complex procedures.

Inventive Principle:

Principle #10Preliminary action

2Loss of information

If PMPR application timing is not specified, then signaling overhead is reduced, but reliability of MPE compliance deteriorates

Engineering Contradiction:

Improvesignaling overheadVSAvoidMPE compliance reliability

Core Design Contradiction:

Loss of informationVSReliability

Solution Approach 1:

The patent merges the PMPR value and its application timing indication into a single MAC CE message. This combined approach ensures that both the power reduction value and when it should be applied are transmitted together, maintaining MPE compliance reliability while minimizing additional signaling overhead through efficient message consolidation.

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If PMPR is applied without clear timing indication, then system throughput is maintained, but harmful radiation increases due to improper power control

Engineering Contradiction:

Improvesystem throughputVSAvoidradiation exposure

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent implements feedback by including the application timing indication in the PMPR MAC CE message. This provides the UE with clear feedback on when to apply the power reduction, enabling proper power control that limits radiation exposure while maintaining system throughput through accurate and timely power management.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12634836B2Power headroom report medium access control-control element for indicating power management maximum power reduction

Publication Date: 2026.05.19 NTT DOCOMO INC

AI summary

A terminal according to one aspect of the present disclosure includes: a transmission section that transmits a first medium access control-control element (MAC CE) including power-management maximum power reduction (PMPR) and a first value indicating an application timing of the PMPR; and a control section that controls transmission of an uplink (UL) signal based on the PMPR. According to one aspect of the present disclosure, it is possible to clarify applied PMPR.