RF Exposure Compliance via Dynamic Transmit Power Scaling

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Solution Overview

Problem

Wireless communication devices face challenges in complying with multiple radio frequency (RF) exposure limits, including time-averaged RF exposure limits and total RF energy specifications, which require efficient transmit power management to ensure compliance without compromising communication performance.

Innovation Solution

A method and apparatus that obtain scaling information to adjust transmit power based on the relationship between RF exposure limits, allowing for compliance with both time-averaged and total RF energy specifications by applying scaling factors to transmit powers, ensuring that the maximum allowed time-averaged transmit power is scaled accordingly to maintain compliance across various RF exposure scenarios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If transmit power is increased to improve communication performance, then throughput and transmission range are improved, but RF exposure limits are exceeded

Engineering Contradiction:

ImprovethroughputVSAvoidRF exposure

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic transmit power adjustment by continuously monitoring cumulative transmit power over time intervals and comparing against RF exposure limits. The system dynamically scales transmit power based on real-time conditions, transitioning between different power levels to maintain compliance while optimizing communication performance.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the transmit power parameter adaptively by applying scaling factors to adjust power levels. When cumulative power approaches regulatory limits, the system reduces transmit power; when limits allow, it increases power to improve throughput, thus optimizing the parameter within safe boundaries.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If transmit power is reduced to comply with RF exposure limits, then RF exposure compliance is improved, but communication performance deteriorates

Engineering Contradiction:

ImproveRF exposure complianceVSAvoidcommunication performance

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent implements periodic assessment of cumulative transmit power over defined time intervals (e.g., 6-minute averaging periods). By evaluating power exposure periodically rather than continuously, the system can allow higher power transmissions within safe cumulative limits while ensuring long-term compliance with RF exposure regulations.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system performs preliminary calculations of scaling factors based on predicted cumulative power exposure. By anticipating future power levels and adjusting current transmit power accordingly, the system ensures compliance is maintained proactively rather than reactively, preventing performance degradation from abrupt power reductions.

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If multiple RF exposure limits are enforced simultaneously, then compliance accuracy is improved, but system complexity increases

Engineering Contradiction:

Improvecompliance accuracyVSAvoidpower management complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple RF exposure limit requirements into a unified power management framework. By consolidating different regulatory limits (e.g., SAR, PD, and total power limits) into a single cumulative power assessment mechanism, the system achieves comprehensive compliance without managing separate complex control systems for each limit.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The system introduces scaling factors as intermediary variables that mediate between raw transmit power and RF exposure limits. These scaling factors simplify the enforcement of multiple limits by providing a unified adjustment mechanism that automatically accounts for different regulatory requirements without complex decision logic.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Productivity

If transmit power is optimized for throughput, then productivity is improved, but energy consumption increases

Engineering Contradiction:

ImprovethroughputVSAvoidenergy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent applies partial power transmission by transmitting at the maximum power level allowed by RF exposure constraints rather than always using full available power. This partial action approach achieves sufficient throughput for communication needs while avoiding excessive energy consumption that would occur with continuous full-power transmission.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS20250097858A1Radio frequency exposure limit compliance considering total energy specification

Publication Date: 2025.03.20 QUALCOMM INC

AI summary

Certain aspects of the present disclosure provide techniques and apparatus for multi-radio frequency exposure limit compliance. An example method of wireless communication includes obtaining scaling information indicative of a relationship between a first radio frequency (RF) exposure limit and a second RF exposure limit. The method further includes transmitting a signal at a transmit power determined based at least in part on a maximum allowed transmit power for a time interval and the scaling information.