Power Headroom Reporting Triggering for Asymmetric UL TRPs

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Solution Overview

Problem

In asymmetric UL TRP deployment scenarios, periodic PHR reporting induces latency, and triggering PHR by downlink pathloss changes is unreliable, leading to inefficient uplink channel throughput.

Innovation Solution

Network-triggered power headroom reporting is implemented, where the network requests a PHR via a downlink channel, and the UE transmits it on an uplink channel, using dedicated or piggybacked MAC CEs, with resource determination based on uplink grants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If periodic PHR reporting is used, then the uplink channel throughput is maintained, but latency is introduced

Engineering Contradiction:

Improveuplink channel throughputVSAvoidreporting latency

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent implements periodic PHR reporting at configured intervals (e.g., every 10ms, 20ms, or 40ms) to maintain uplink channel throughput. The periodic timing is configurable by the network to balance between timely power information updates and latency reduction, allowing the system to achieve necessary reporting frequency without excessive latency

Inventive Principle:

Principle #19Periodic action

2Productivity

If PHR is triggered by downlink pathloss changes, then reporting frequency is increased, but reliability deteriorates in asymmetric UL TRP scenarios

Engineering Contradiction:

Improvereporting frequencyVSAvoidtriggering reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent enables the network to autonomously determine when PHR reporting is needed based on uplink power changes detected at the TRP. The network monitors uplink signal power and triggers PHR requests independently of downlink pathloss measurements, making the triggering mechanism self-adaptive to actual uplink conditions and reliable in asymmetric scenarios where downlink and uplink pathloss may differ

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent implements a feedback mechanism where the network monitors uplink power changes and sends PHR requests to the UE when reporting is deemed necessary. This closed-loop feedback ensures PHR is triggered based on actual uplink power variations rather than unreliable downlink pathloss indicators, improving triggering reliability

Inventive Principle:

Principle #23Feedback

3Reliability

If network-triggered PHR reporting is implemented, then reporting reliability is improved, but system complexity increases

Engineering Contradiction:

ImprovePHR reporting reliabilityVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a network-controlled intermediary mechanism where the base station acts as a mediator between the UE's power transmission and the PHR reporting process. The network receives uplink signals, determines power changes, and triggers PHR requests accordingly, simplifying the UE's decision-making while maintaining high reporting reliability through network-level power monitoring

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP4694394A1Communication apparatus and base station involved in power headroom reporting

Publication Date: 2026.02.11 PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA

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AI summary

Provided are a communication apparatus, a base station, and communication methods for a communication apparatus and, respectively, a base station. The communication apparatus comprises: a transceiver, which, in operation, receives a request for a power headroom report, PHR; and circuitry, which, in operation, generates the requested PHR. The transceiver, in operation, transmits the requested PHR.