Predictive Sectorized Average Power Control for RF EMF Compliance
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Solution Overview
Problem
Existing wireless communication systems with advanced antenna systems (AAS) face challenges in complying with RF EMF exposure regulations due to increased beamforming gain, leading to larger exclusion zones and frequent momentary power limitations, which affect throughput.
Innovation Solution
A directional average power control algorithm that employs multiple spatial controllers to ensure the average power remains below regulatory thresholds by dynamically limiting scheduled resources, using beamforming gains and predictive power control to maintain compliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If advanced antenna systems with beamforming are deployed to increase capacity and coverage, then beamforming gain is significantly increased, but exclusion zones become significantly larger
Solution Approach 1:
The patent divides the spatial coverage into multiple sectors, each with its own average power control mechanism. Instead of applying a single uniform power limit across the entire cell, the system calculates and applies sector-specific power limits based on the directional beamforming characteristics of each sector, thereby reducing the effective exclusion zone area while maintaining beamforming gain.
Solution Approach 2:
The patent implements local average power control for each sector, allowing different power limits to be applied to different spatial regions. Each sector receives customized power control parameters based on its specific beamforming characteristics and exposure requirements, rather than applying a uniform global limit that would unnecessarily restrict beamforming gain.
2Reliability
If cell-wide average power control is applied to meet RF EMF regulations, then regulatory compliance is achieved, but momentary throughput is significantly limited
Solution Approach 1:
The patent segments the cell-wide power control into sector-specific power control mechanisms. Each sector is independently controlled with its own average power limits calculated based on local beamforming characteristics. This segmentation allows the system to maintain RF EMF compliance in each sector while avoiding the overly conservative global limits that would unnecessarily restrict momentary throughput.
Solution Approach 2:
The patent implements dynamic average power control that adapts to changing transmission conditions in each sector. The power limits are continuously adjusted based on real-time measurements of average power density and beamforming gain, allowing the system to optimize throughput while maintaining compliance. This dynamic adjustment enables higher momentary power levels when safe, thereby improving throughput compared to static cell-wide limits.
3Ease of operation
If dynamic average power control is implemented to reduce exclusion zones, then deployment challenges are reduced, but control system complexity increases
Solution Approach 1:
The patent divides the complex cell-wide control problem into multiple simpler sector-specific control problems. Each sector controller operates independently with standardized algorithms, making the overall system more manageable and easier to deploy. The segmentation allows for modular implementation where each sector can be configured and monitored separately, reducing the operational complexity despite the increased number of control mechanisms.
Solution Approach 2:
The patent implements feedback mechanisms in each sector controller that continuously monitor average power density and adjust power limits accordingly. This feedback approach simplifies the control system by using automatic adjustment rather than complex manual configuration. The feedback loops continuously adapt to changing conditions, reducing the need for manual intervention and simplifying deployment while maintaining effective control.
Data Source
AI summary
A method and network node for predictive sectorized average power control. A method includes determining a beamforming gain for each of a plurality of directions. The method also includes determining a total power at each of a plurality of times within a window for each of the plurality of spatial directions, the total power being based at least in part on a weighted sum of products of a beamforming gain and a downlink power allocated to a wireless device in each of the plurality of spatial directions. The method further includes determining an average of the total power within the window to produce an average power; computing a control signal based on the average power and a threshold; and controlling the transmitted total power according to the control signal by limiting a fraction of scheduled physical resource blocks to an upper limit.