Time Blanked Scheduling for Average EIRP Regulation
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Solution Overview
Problem
Advanced antenna systems (AAS) in wireless communication networks increase beamforming gain, leading to higher momentary RF exposure power density, which can exceed safety limits, necessitating control of average power to maintain compliance distances and adhere to RF exposure regulations.
Innovation Solution
A method for controlling a radio transmitter by determining allowable average output power and scheduling physical resource blocks (PRBs) within a control window to ensure compliance with RF exposure limits, using a recursive calculation to set hard limits on PRBs based on past and future output power profiles, and implementing blanking of slots to regulate power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If beamforming gain is increased using advanced antenna systems, then coverage and capacity are improved, but momentary RF exposure power density increases and may exceed safety limits
Solution Approach 1:
The patent applies periodic action by implementing time-averaged power control where the transmitter operates in cycles of high-power beamformed transmission followed by lower-power intervals. The system calculates allowable average output power over a control window and schedules PRBs proportionally across future slots, creating a periodic pattern that maintains RF exposure compliance while achieving coverage enhancement through beamforming gain during active transmission periods.
2Object-affected harmful factors
If average output power is reduced to meet RF exposure limits, then RF exposure compliance is improved, but the control range and flexibility of power control systems deteriorates
Solution Approach 1:
The patent implements dynamics by making the power control system adaptive and flexible through proportional PRB scheduling across multiple future slots. Instead of fixed power reduction, the system dynamically calculates the first limit on PRBs based on allowable average output power and adjusts scheduling proportionally. This dynamic approach maintains control range by allowing the system to adapt to varying traffic conditions while ensuring RF exposure compliance through the control window mechanism.
3Object-affected harmful factors
If PRB scheduling is constrained to meet average power limits, then RF exposure compliance is improved, but scheduling flexibility and system productivity deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the control window into multiple future slots and distributing PRB scheduling proportionally across them. Instead of constraining each individual slot, the system segments the average power calculation across the control window, allowing flexible PRB allocation in each slot while maintaining overall compliance. This segmentation preserves scheduling flexibility by enabling traffic-dependent PRB assignment in each slot subject to the averaged power constraint.
Data Source
AI summary
Embodiments of a method in a network node for controlling a radio transmitter. In each one of a plurality of consecutive control steps spanning a predetermined control window, determining a first limit representing a number of physical resource blocks, PRBs, that can be scheduled in each one of a plurality of consecutive future slots of a current control step, based at least in part on an allowable average output power of the radio transmitter. The control window comprises a plurality of control steps, and each control step comprises a plurality of slots. When the determined first limit is less than or equal to a pre-configured second limit representing a number of PRBs that can be scheduled in a single slot, scheduling PRBs in a proportion of the plurality of consecutive future slots of the current control step, the proportion being calculated such that an averaged fraction of scheduled PRBs in the current control step is less than or equal to the first limit.