5G mmW Base Station Power Control via RFIC Signal Sampling
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Solution Overview
Problem
Current 5G mmW base stations with advanced antenna systems face challenges in achieving accurate short-term average power measurement close to antenna elements, which is crucial for RF EMF exposure compliance, due to the complexity of digital beamforming and the need for precise power control to avoid exceeding regulatory limits.
Innovation Solution
A method involving capturing signal samples from RFICs associated with antenna elements, summing these samples to obtain a short-term average power value, and using a dynamic scheduler limiter with proportional-integrating control to ensure compliance with RF EMF exposure regulations, while avoiding systematic errors through deterministic and random sampling techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If digital beamforming with IFFT processing is used to enable frequency selective beamforming, then adaptability is improved, but device complexity increases due to required IFFT processing in RFICs or increased interface bandwidth for baseband IFFT processing
Solution Approach 1:
The patent extracts the IFFT processing function from the RFIC and relocates it to the baseband unit. This separation removes the complexity burden from the RFIC while preserving the frequency selective beamforming capability. The baseband unit performs the computationally intensive IFFT operations, and only the resulting time-domain signals need to be transmitted to the RFICs via standard interfaces.
2Reliability
If beam sweeping or wider initial beams are used to improve initial access and coverage, then reliability is improved, but loss of time increases due to additional overhead for beam management
Solution Approach 1:
The patent implements dynamic beam management where the baseband unit can rapidly reconfigure beamforming weights in the digital domain. This dynamic capability allows the system to perform initial access with wider beams when needed, then quickly switch to narrower, more precise beams for data transmission, reducing the time overhead compared to static analog beamforming systems that require extensive beam sweeping.
3Object-affected harmful factors
If power control is implemented to ensure RF EMF exposure compliance, then safety is improved, but device complexity increases due to need for accurate short-term average power measurement
Solution Approach 1:
The patent introduces the baseband unit as an intermediary that performs the complex power measurement and control functions. The baseband unit captures signal samples from each RFIC, calculates short-term average power values, and applies control adjustments. This intermediary approach centralizes the measurement complexity in the baseband unit rather than distributing it across multiple RFICs, simplifying the overall system architecture while ensuring accurate RF EMF compliance monitoring.
Data Source
AI summary
There is provided a method at a network node equipped with an advance antenna system, AAS. The AAS comprises a plurality of antenna elements and one or more radio frequency integrated circuits, RFICs. Each of the one or more RFICs is associated with one or more of the plurality of antenna elements. The method comprising: capturing a plurality of signal samples of one or more signal chains of each of the one or more RFICs. Each of the one or more signal chains correspond to one or more of the plurality of antenna elements and a signal sample is associated with an envelope power level at an output of the respective signal chain; and summing at least a subset of the plurality of signal samples to obtain a short term average power value at the AAS.