WTRU Power Averaging for Multi-Band SAR and MPE Mitigation

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Solution Overview

Problem

Existing wireless communication devices face challenges in managing specific absorption rate (SAR) and maximum permitted exposure (MPE) regulatory requirements, particularly in monitoring radiation exposure across multiple frequency bands and ensuring compliance with defined limits.

Innovation Solution

A wireless transmit/receive unit (WTRU) is configured to monitor radiation exposure by determining averaged power over an evaluation period, comparing it against SAR and/or MPE limits, and adjusting transmission power based on predefined thresholds and network entity feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the WTRU transmits at high power to maintain communication quality and productivity, then communication performance is improved, but radiation exposure levels increase causing SAR and MPE compliance issues

Engineering Contradiction:

Improvecommunication performanceVSAvoidradiation exposure

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The WTRU dynamically adjusts its transmission power based on real-time monitoring of power density measurements and duty cycle calculations. The transmission power is not fixed but varies adaptively to maintain communication performance while staying within SAR and MPE limits, resolving the contradiction between high power transmission and radiation exposure control

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The WTRU implements a feedback mechanism where it continuously measures power density, calculates duty cycle, compares against thresholds, and adjusts transmission power accordingly. This closed-loop control system ensures that communication performance is maintained while preventing excessive radiation exposure, directly addressing the technical contradiction

Inventive Principle:

Principle #23Feedback

2Reliability

If the WTRU continuously monitors power density across multiple frequency bands to ensure SAR and MPE compliance, then regulatory compliance is improved, but device complexity and energy consumption increase

Engineering Contradiction:

Improveregulatory complianceVSAvoidmonitoring system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The WTRU employs a universal monitoring framework that operates across multiple frequency bands (FR1 and FR2) using a single integrated power density measurement and duty cycle calculation mechanism. This multi-functional approach ensures SAR and MPE compliance across all bands without requiring separate monitoring systems for each frequency range, thereby improving regulatory compliance while limiting the increase in device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The monitoring system adapts its measurement and evaluation parameters based on the operating frequency band. Different evaluation periods and power density thresholds are applied for FR1 versus FR2, allowing the system to maintain compliance with varying regulatory requirements while optimizing the complexity of the monitoring mechanism for each specific band

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If the WTRU applies aggressive power reduction to ensure SAR and MPE compliance, then radiation exposure control is improved, but communication reliability and data throughput decrease

Engineering Contradiction:

Improveradiation exposure controlVSAvoidcommunication reliability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The WTRU applies partial power reduction only when and where necessary to meet SAR and MPE requirements, rather than uniformly reducing power across all transmissions. By calculating duty cycle and comparing against thresholds, the system applies just enough power reduction to ensure compliance while maintaining maximum possible communication reliability and throughput in compliant conditions

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The power adjustment mechanism applies different power levels to different frequency bands and time periods based on local compliance requirements. FR1 and FR2 bands receive differentiated treatment based on their specific SAR and MPE limits, allowing optimal communication performance in each band while ensuring local compliance, thus balancing radiation control with communication reliability

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20260025768A1Specific absorption rate and maximum permitted exposure mitigation

Publication Date: 2026.01.22 INTERDIGITAL PATENT HOLDINGS INC

AI summary

Systems for performing radiation exposure monitoring that accommodate operating in multiple frequency bands are provided. A WTRU may be configured to monitor radiation exposure by determining an averaged power over an evaluation period. The radiation may be measured over a moving averaging window. The averaged measured power may be compared against SAR or MPE limits which may be defined in terms of normalized fractions or ratios in dB. The WTRU may be configured to measure for an averaged power periodically and/or in response to triggers.