Mobile Station PHR Timer Management for Multi-RAT Power Control

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Solution Overview

Problem

In conventional mobile communication systems, mobile stations may fail to properly transmit Power Headroom Reports (PHR) when there are changes in transmission power or Maximum Power Reduction (MPR) during simultaneous communication through different Radio Access Technologies (RATs, leading to suboptimal adjustments in transmission format, resulting in degraded frequency use efficiency or increased data errors.

Innovation Solution

A mobile station equipped with a reporting unit and timer management system that manages two timers to strategically report surplus transmission power, adjusting based on predetermined thresholds and timer durations to ensure accurate backoff considerations across multiple RATs, thereby facilitating proper power adjustments and format changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single timer is used to control PHR transmission, then device complexity is reduced, but reliability of power backoff consideration deteriorates when transmission power changes frequently between RATs

Engineering Contradiction:
Improvetimer management complexityVSAvoidpower backoff consideration reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent divides the single timer control mechanism into two separate timers: prohibitPHR-Timer_up for power increase events and prohibitPHR-Timer_down for power decrease events. This segmentation allows independent control of PHR transmission suppression for upward and downward power changes, ensuring that power backoff considerations remain reliable even when transmission power changes frequently between different RATs.

Inventive Principle:
Principle #1Segmentation

2Productivity

If PHR transmission is suppressed during timer activation, then frequency use efficiency is improved by preventing unnecessary reports, but adaptability to rapid power changes deteriorates

Engineering Contradiction:
Improvefrequency use efficiencyVSAvoidadaptability to rapid power changes
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic timer management where the prohibitPHR-Timer_up and prohibitPHR-Timer_down are activated based on the direction of power change. When transmission power increases, prohibitPHR-Timer_up is activated to suppress unnecessary PHR reports and improve frequency efficiency. When transmission power decreases, prohibitPHR-Timer_down is activated to allow timely PHR transmission for rapid adaptation. This dynamic approach balances frequency efficiency with adaptability to rapid power changes.

Inventive Principle:
Principle #15Dynamics

3Productivity

If transmission power is increased in one RAT, then communication performance in that RAT is improved, but SAR provision compliance may be violated requiring power backoff

Engineering Contradiction:
Improvecommunication performanceVSAvoidSAR violation risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent employs feedback mechanisms where the mobile station monitors transmission power levels across multiple RATs and determines when to activate prohibitPHR-Timer_up or prohibitPHR-Timer_down based on power change directions. This feedback loop ensures that when power increases in one RAT potentially violating SAR provisions, the system responds by suppressing PHR transmission during the timer period, allowing the base station to adjust transmission format and enforce power backoff to maintain SAR compliance.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2677806B1Mobile station
Publication Date: 2016.05.04 NTT DOCOMO INC
  • EP2677806B1 patent drawingFigure 1~2
  • EP2677806B1 patent drawingFigure 3
  • EP2677806B1 patent drawingFigure 4

AI summary

In a mobile station UE according to a present invention, a PHR transmission unit 11 transmits a PHR to a RAT#1 when "prohibitPHR-Timer_up" is interrupted and when an increment in transmission power or P-MPR in second communication exceeds "dl-PathlossChange" compared with a value in finally transmitting the PHR. When "prohibitPHR-Timer_down" is interrupted and when a decrement in transmission power or a decrement in transmission power or P-MPR in the second communication exceeds "dl_PathlossChange", the PHR transmission unit 11 transmits the PHR to the RAT#1, and "prohibitPHR-Timer_up" is ended in a period shorter than that of "prohibitPHR-Timer_down".