Massive MIMO Beamforming for EMF Safety Compliance

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Solution Overview

Problem

The deployment of Massive MIMO base stations with hundreds of antennas poses challenges in meeting electromagnetic field (EMF) safety regulations due to the large exclusion zones required, which are impractical in real estate-constrained areas, necessitating innovative methods to dynamically regulate transmission power and beamforming to ensure safe EMF levels.

Innovation Solution

A method that involves using proximity sensors and spatio-temporal transmission profile variations, including reducing transmit power, scheduling frequency, and generating beam nulls, to dynamically adjust the electromagnetic field distribution around base stations, ensuring compliance with EMF safety regulations even in scenarios where the exclusion zone alone may not suffice.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If beamforming gains are used to increase cell throughput and SINR, then receive power increases, but the size of the exclusion zone around the base station increases

Engineering Contradiction:
Improvecell throughputVSAvoidexclusion zone size
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The patent implements dynamic beamforming that adapts beam directions and power distribution in real-time based on the presence of entities in exclusion zones. When an entity is detected, the system dynamically adjusts beamforming parameters to redirect or reduce power toward that entity while maintaining service to legitimate users, thus reducing exclusion zone size without sacrificing throughput.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system applies different transmission characteristics to different spatial regions. By identifying the location of entities within the exclusion zone, the base station applies localized power reduction or beam nulling only in the directions where entities are present, while maintaining full power and beamforming gains in other directions where no entities are present, thereby preserving overall productivity.

Inventive Principle:
Principle #3Local quality

2Productivity

If multiple antennas are used to serve multiple user equipment simultaneously, then cell throughput increases, but the electromagnetic field absorption by humans increases

Engineering Contradiction:
Improvecell throughputVSAvoidEMF absorption by humans
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system employs proximity sensors to detect the presence of entities in real-time and uses this feedback to continuously adjust beamforming parameters. When entities are detected in the exclusion zone, the system modifies transmission patterns to reduce EMF exposure while maintaining service to users outside the exclusion zone, thus resolving the contradiction between productivity and harmful effects.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent implements dynamic adaptation of multi-antenna transmission patterns based on real-time detection of entity presence. The system can switch between different beamforming configurations, power distribution schemes, and antenna activation patterns to minimize EMF absorption by humans while maintaining high throughput when no entities are present in sensitive areas.

Inventive Principle:
Principle #15Dynamics

3Area of stationary object

If transmit power is reduced to decrease exclusion zone size, then EMF safety is improved, but cell throughput and signal quality deteriorate

Engineering Contradiction:
Improveexclusion zone sizeVSAvoidcell throughput
Core Design Contradiction:
Area of stationary objectVSProductivity

Solution Approach 1:

Instead of uniformly reducing transmit power in all directions, the system applies localized power reduction only toward detected entities within the exclusion zone. Beamforming techniques concentrate power in specific spatial directions, and when entities are detected, the system creates transmission nulls or reduces power only in those specific directions while maintaining full power in other directions, thus preserving overall throughput while reducing exclusion zone size.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system dynamically adjusts transmit power levels based on real-time detection of entity presence. When no entities are present in the exclusion zone, the system operates at full power to maximize throughput. When entities are detected, the system dynamically reduces power only in the directions where entities are present, thus maintaining high productivity when safe while protecting human health when needed.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach effectively reduces EMF levels to safe values in real-time, allowing for the lawful deployment of Massive MIMO base stations in densely populated areas by dynamically adapting transmission power and beamforming to mitigate EMF exposure risks, thereby reducing the physical extent of exclusion zones.

Implementation Method 1

an array of antenna elements to generate a directionally selective beam profile for the node

Methodology Applied
Scientific EffectBeamforming: Focusing

Implementation Method 2

the processor can further generate one or more commands to cause the node to produce a null point in the beam profile for the node

Methodology Applied
Scientific EffectNulling: Interference

Implementation Method 3

The node can further comprise a proximity sensor to detect the presence of an entity with the region of interest

Methodology Applied
Scientific EffectProximity sensing:

Data Source

PatentEP3518587B1Regulating transmission powers from nodes
Publication Date: 2022.04.06 NOKIA SOLUTIONS & NETWORKS OY
  • EP3518587B1 patent drawingFigure 1~2
  • EP3518587B1 patent drawingFigure 3
  • EP3518587B1 patent drawingFigure 4

AI summary

A method for modifying an electromagnetic field distribution of a node in a telecommunication network, comprising determining the presence of an entity within a region of interest, and regulating transmission power to the region of interest from the node by varying a spatiotemporal transmission profile of the node in response to determining the presence of the entity in the region for a period of time longer than a predetermined threshold value, wherein modifying the electromagnetic field distribution of the node comprises modifying an average electromagnetic field distribution of said node.