Wireless Device Power Control for RF EMF Compliance
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Solution Overview
Problem
Current wireless communication systems with advanced antenna systems (AAS) face challenges in dynamically and smoothly limiting scheduled resources to comply with RF EMF exposure regulations, particularly in maintaining time-averaged radiated power within safety margins, due to the lack of effective actuator mechanisms and feedback control systems that can adjust power based on averaged output power and beamforming gains.
Innovation Solution
A method is introduced to compute the time-averaged power for codebook-based and reciprocity-assisted beamforming by dividing the directional space into bins, calculating the power contribution of each bin based on scheduled power and antenna gain, and implementing back-off power feedback control to maintain compliance with RF EMF exposure regulations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If beamforming transmission is used to improve signal directionality and coverage, then communication performance is improved, but RF EMF exposure to specific directions increases and becomes harder to control
Solution Approach 1:
The patent divides the directional space into multiple bins (e.g., 8 bins covering different angular regions) to segment the RF energy distribution. This allows independent control and monitoring of power levels in each directional sector, enabling selective power limitation to comply with RF EMF exposure regulations while maintaining communication performance in acceptable directions.
Solution Approach 2:
The patent implements a feedback control mechanism where the average power in each bin is continuously monitored and fed back to adjust the scheduled resources. Based on the computed average power and predefined thresholds, the system dynamically modifies transmission parameters to maintain RF EMF compliance while optimizing communication performance.
2Reliability
If dynamic power adjustment is implemented to comply with RF EMF regulations, then safety compliance is improved, but system complexity increases due to lack of actuator mechanisms and feedback control
Solution Approach 1:
The patent introduces a feedback control loop that monitors average power in each bin and adjusts scheduled resources accordingly. The controller receives power information, compares it against thresholds, and modifies transmission parameters to maintain compliance with RF EMF regulations while managing system complexity through automated control.
Solution Approach 2:
The system dynamically changes transmission parameters such as scheduled resources and power levels based on computed average power in each bin. By adjusting these parameters in response to real-time power measurements, the system achieves RF EMF compliance without requiring complex hardware modifications.
3Object-affected harmful factors
If time-averaged power is monitored to ensure safety compliance, then RF EMF exposure control is improved, but measurement and computation complexity increases
Solution Approach 1:
The patent segments the directional space into bins to simplify power measurement and monitoring. By organizing the measurement task into discrete angular regions, the system can compute time-averaged power for each bin more efficiently, reducing the overall complexity of RF EMF exposure control while maintaining comprehensive monitoring capability.
Data Source
AI summary
Disclosed are methods and apparatuses. The method implemented at a wireless device may comprise computing an average power for a bin covering a portion of a total solid angle covered by an antenna array of the wireless device by averaging a momentary power for the bin over a time period, wherein the momentary power is computed based on respective scheduled power of at least one beamforming transmission and respective antenna gain of the at least one beamforming transmission in the bin (302, 606, 702, 802, 902, 1002). The method may further comprise performing a back-off power feedback control for the bin based on the computed average power (304, 608, 708, 808, 908, 1006).