Error Scaling in Crest Factor Reduction Circuits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional crest factor reduction techniques in wireless communication systems face challenges such as inefficiency in power amplifiers due to high peak-to-average power ratios, leading to wasted power and thermal issues, and introduce in-band noise and spectral regrowth, which complicates transmitter architectures and reduces link budget.
Innovation Solution
A method and system for error scaling in crest factor reduction (CFR) circuits that dynamically adjusts the error scaling factor based on the input signal level, target signal-to-noise ratio, and processed error signal level to regulate the peak-to-average power ratio and achieve a target error vector magnitude, allowing for continuous or iterative clipping, filtering, and scaling to optimize signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If non-linear crest factor reduction techniques (clipping and filtering) are used, then spectral regrowth is contained, but transmitter complexity increases significantly due to multiple filtering iterations
Solution Approach 1:
The patent implements dynamic error scaling where the scaling factor is adjusted based on the input signal characteristics and desired output properties. This allows the filtering process to adapt to different signal conditions, achieving spectral regrowth containment with reduced complexity by avoiding fixed multiple iterations.
Solution Approach 2:
The patent changes the scaling parameter dynamically to optimize the balance between spectral regrowth suppression and complexity. By adjusting the error scaling factor based on signal properties, the system achieves effective spectral containment without requiring multiple fixed filtering iterations.
2Object-generated harmful factors
If multiple iterations of clipping and filtering are performed, then spectral regrowth is better contained, but Error-Vector Magnitude increases and link budget decreases
Solution Approach 1:
The patent applies continuous error scaling throughout the signal processing chain, maintaining optimal scaling at each stage rather than using discrete multiple iterations. This continuous approach preserves signal quality and link budget while effectively containing spectral regrowth.
Solution Approach 2:
The system uses feedback mechanisms to monitor signal properties and adjust the error scaling factor accordingly. This feedback control allows the system to achieve spectral regrowth containment while maintaining link budget by avoiding excessive scaling that would degrade signal quality.
3Reliability
If linear crest factor reduction techniques are used, then signal quality is maintained, but additional information must be transmitted about the coding scheme, reducing spectral efficiency
Solution Approach 1:
The patent converts the harmful non-linear distortion into a controlled process by using dynamic error scaling. The scaling factor is optimized to minimize the impact on signal quality while maintaining the benefits of non-linear CFR, effectively turning a potential disadvantage into an advantage.
Data Source
AI summary
A method and system for error scaling for crest factor reduction (CFR) are disclosed. According to one aspect, a method for regulating peak to average power ratio (PAR) of an output signal of the CFR circuit is disclosed. In one embodiment, the method includes receiving an input signal at an input of the CFR circuit. The magnitude of the input signal is determined and clipped to a target level to produce an error signal by comparing the input signal magnitude to a threshold in a comparator. The error signal is filtered to produce a processed error signal. The filter provides a bandpass filter frequency response. The PAR of the output signal is regulated by scaling the processed error signal by an error scaling factor to achieve a target signal to noise ratio (SNR) for the output signal corresponding to a target error vector magnitude (EVM).