Beam-Specific RACH Power Control for RF Exposure Compliance

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Solution Overview

Problem

Conventional RACH procedures in mmWave and 5G networks fail to account for the varying RF exposure requirements of different beams, leading to undesirably large output power reduction or small duty cycles, which hinder data activity and coverage.

Innovation Solution

The UE independently determines output power reduction and duty cycle for each beam based on RF exposure requirements, selecting RACH occasions that meet MPE targets, enhancing data activity and coverage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional RACH procedures are used without beam-specific RF exposure considerations, then the procedure is simple to implement, but output power reduction is excessively large and duty cycle is small, hindering data activity and coverage

Engineering Contradiction:
Improvedata activityVSAvoidRACH procedure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the RACH procedure into beam-specific operations where the UE independently determines output power reduction and duty cycle for each beam based on RF exposure requirements. This segmentation allows tailored power control per beam rather than applying uniform restrictions across all beams, thereby improving data activity without requiring complete procedural redesign

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic determination of output power reduction and duty cycle parameters. Instead of using fixed or preconfigured values, the UE dynamically adjusts these parameters for each beam based on real-time RF exposure requirements, enabling optimized power and duty cycle adjustments that improve productivity while maintaining manageable complexity through standardized dynamic adjustment mechanisms

Inventive Principle:
Principle #15Dynamics

2Reliability

If uniform output power reduction is applied across all beams, then the implementation is straightforward, but RF exposure requirements cannot be optimized for individual beams, reducing network performance

Engineering Contradiction:
ImproveRF exposure complianceVSAvoidpower control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by enabling the UE to independently determine output power reduction and duty cycle for each individual beam based on its specific RF exposure requirements. This allows different power control parameters to be applied to different beams locally, ensuring RF exposure compliance is optimized for each beam's characteristics rather than applying a uniform approach across all beams

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements self-service by allowing the UE to autonomously determine and adjust its own output power reduction and duty cycle parameters for each beam. The UE independently evaluates RF exposure requirements and applies appropriate power control without requiring complex network coordination or centralized control, thereby achieving reliable RF exposure compliance with moderate complexity

Inventive Principle:
Principle #25Self-service

3Productivity

If preconfigured MPE parameters are used, then the system is easy to operate, but the parameters cannot be optimized for specific beams, limiting network performance

Engineering Contradiction:
Improvenetwork performanceVSAvoidparameter configuration
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent transitions from static preconfigured MPE parameters to dynamic determination where the UE independently calculates output power reduction and duty cycle for each beam based on actual RF exposure requirements. This dynamic approach enables optimized network performance for each beam while maintaining ease of operation through standardized dynamic adjustment procedures that do not require complex configuration

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3963750B1Enhancing RACH operation in new radio under RF exposure requirements
Publication Date: 2025.08.20 NOKIA TECHNOLOGIES OY
  • EP3963750B1 patent drawingFigure 1
  • EP3963750B1 patent drawingFigure 2
  • EP3963750B1 patent drawingFigure 3

AI summary

A technique of accounting for the difference in required output power reduction or required duty cycle when selecting the RO in addition to the DL RS. Both output power reduction and duty cycle are independently determined by UE itself (i.e., UE needs to be able to determine itself required power backoff and/or duty cycle in order to meet RF exposure requirements). Advantageously, a RACH procedure in which the UE determines both output power reduction and duty cycle independently enables better choices of output power reduction and duty cycle, enhancing data activity and coverage.