Beam Steering Crest Factor Reduction Clip Noise
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Solution Overview
Problem
Conventional crest factor reduction techniques in wireless communications introduce clipping noise that interferes with signal reception by steering it in the same direction as the data signal, leading to reduced signal quality and power amplifier inefficiency.
Innovation Solution
The method involves generating a clipping noise signal with a different amplitude-phase relationship than the input signal, allowing it to be steered in a different direction than the data signal, thereby increasing signal-to-noise ratios and enhancing power amplifier performance by reducing the peak-to-average ratio without degrading the signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional crest factor reduction techniques introduce clipping noise with the same amplitude-phase relationship as the input signal, then the peak-to-average ratio is reduced, but the clipping noise interferes with signal reception and reduces signal quality
Solution Approach 1:
The patent applies asymmetry by introducing a phase shift between the clipping noise signal and the original data signal. Specifically, the clipping noise signal is generated with a different amplitude-phase relationship, causing it to be steered in a different direction than the data signal. This asymmetric treatment separates the harmful clipping noise from the useful signal direction, reducing interference at receivers while maintaining peak-to-average ratio reduction benefits
Solution Approach 2:
The patent transitions from a single-dimension signal processing approach to a multi-dimensional approach by considering spatial direction as an additional dimension. By adjusting the amplitude and phase parameters of the clipping noise signal independently, the system steers the clipping noise in a different spatial direction than the data signal, effectively separating them in the spatial domain and reducing harmful interference
2Loss of energy
If clipping noise is steered in the same direction as the data signal, then the power amplifier operates more efficiently, but the signal-to-noise ratio at receivers deteriorates
Solution Approach 1:
The patent applies local quality by treating different spatial regions differently. The data signal is steered toward desired reception directions with high quality, while the clipping noise signal is steered toward different directions where it causes minimal interference. This localized quality control allows the system to optimize both power amplifier efficiency and signal-to-noise ratio by assigning different spatial qualities to different signal components
Solution Approach 2:
The patent uses phase and amplitude parameters as intermediaries to control the directional characteristics of the clipping noise signal. By adjusting these parameters, the system mediates between the conflicting requirements of power amplifier efficiency and signal-to-noise ratio, enabling the clipping noise to be directed away from receivers while maintaining the benefits of crest factor reduction
Data Source
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AI summary
Signal-to-noise ratios (SNRs) and/or amplifier performance can be improved in crest factor reduction (CFR) applications by steering clipping noise in a different direction than the data signal achieving upon reception. Indeed, using clipping noise signals that have a different amplitude-phase relationship than the input/baseline signal causes the clipping noise signal and data signal to exhibit different antenna patterns, effectively steering the clipping noise in a different direction than the data signal. For instance, clipping noise can be steered away from potential receivers to improve received signal quality. In addition, higher magnitude clipping noise can be used to achieve improved power amplifier performance without increasing received SNR.