Power Headroom Resource Block Allocation for Uplink PA Linearity
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Solution Overview
Problem
5G NR UEs face challenges in maintaining linear operation of power amplifiers to avoid non-linear distortion, leading to reduced uplink performance and coverage due to high peak-to-average power ratio and required power back-off, which is not optimally addressed by existing maximum power reduction (MPR) methods.
Innovation Solution
A network node allocates resource blocks to mobile devices based on power headroom, RF conditions, and network congestion, using inner, outer, or edge resource blocks to optimize power amplifier operation and reduce non-linear distortion, thereby improving performance and coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the PA operates close to saturation for maximum efficiency, then power efficiency is improved, but non-linear distortion increases causing receiver desensitization
Solution Approach 1:
The patent implements dynamic power back-off adjustment where the PA operating point is continuously adapted based on signal conditions. The system calculates required power back-off levels dynamically to maintain linear operation during high PAPR conditions while allowing closer-to-saturation operation during low PAPR conditions, thus resolving the contradiction between efficiency and linearity.
Solution Approach 2:
The patent changes the operating parameter (power level) of the PA based on signal characteristics. By adjusting the PA's operating point according to the instantaneous signal conditions and PAPR levels, the system optimizes the trade-off between power efficiency and distortion generation in real-time.
2Object-generated harmful factors
If power reduction is applied to avoid non-linear distortion, then non-linear distortion is reduced, but uplink performance and coverage decrease
Solution Approach 1:
The system dynamically adjusts the power back-off level based on instantaneous signal conditions rather than applying a fixed reduction. This allows minimal power reduction when not needed (maintaining performance) and appropriate reduction only when signal conditions require it (avoiding distortion).
Solution Approach 2:
The patent implements self-service through the Power Headroom Report mechanism where the UE autonomously monitors its own power conditions and reports back to the network, enabling the system to self-regulate power levels without external intervention, thus maintaining performance while avoiding distortion.
3Productivity
If higher modulation order is used to improve data rate, then spectral efficiency is improved, but power reduction requirements increase
Solution Approach 1:
The patent dynamically adjusts power back-off levels according to modulation order and signal conditions. When higher modulation orders are used, the system calculates appropriate dynamic power back-off to maintain linear operation, allowing the system to achieve high spectral efficiency without excessive fixed power reduction.
4Productivity
If CP-OFDM waveform is used to improve spectral efficiency, then spectral efficiency is improved, but PAPR increases leading to higher power reduction
Solution Approach 1:
The patent implements dynamic power back-off specifically tailored for CP-OFDM's high PAPR characteristics. The system continuously monitors PAPR levels and adjusts power back-off dynamically, allowing CP-OFDM to maintain its spectral efficiency advantage while managing the PAPR-induced power reduction requirements through real-time adaptation.
Data Source
AI summary
The disclosed technology provides a system and method for allocating resource blocks to a wireless device based on a power headroom of the wireless device as contained in a power headroom report (PHR) from the wireless device. The network allocates wireless devices with the highest power headroom (e.g., power headroom above a certain power threshold) with edge resource blocks, wireless devices with the lowest power headroom (e.g. power headroom below a certain power threshold) with inner resource blocks, and other wireless devices with outer resource blocks.