Complex Envelope Clipper Feedback for Lower PAR Error
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Solution Overview
Problem
Existing clipper solutions for reducing peak-to-average power ratio (PAR) in wireless transmit signals increase error values, necessitating the development of more efficient iterative clippers with reasonable complexity.
Innovation Solution
A method involving a complex envelope clipper that forms and subtracts a clipping signal from both the residual and reference signals to remove higher amplitudes, utilizing a calculator and adder to create and apply the clipping signal, thereby reducing PAR without increasing error values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If existing clipper solutions are used to reduce PAR, then the peak-to-average power ratio is reduced, but the error value increases
Solution Approach 1:
The patent implements feedback by using the residual signal from the complex envelope clipper to form a clipping signal, which is then subtracted from both the residual signal and the reference signal. This feedback mechanism allows the system to iteratively reduce PAR while compensating for errors, thereby maintaining lower error values compared to existing clipper solutions.
Solution Approach 2:
The patent introduces a clipping signal as an intermediary element that mediates between the residual signal and the reference signal. By forming the clipping signal based on both signals and subtracting it from both, the system achieves better error performance while reducing PAR, resolving the contradiction between energy efficiency and reliability.
2Reliability
If iterative clippers are designed to reduce error values, then the error performance improves, but the system complexity increases
Solution Approach 1:
The patent segments the clipping process into distinct functional blocks: a complex envelope clipper that generates the residual signal, a calculator that forms the clipping signal based on the residual and reference signals, and adders that subtract the clipping signal from both signals. This segmentation allows the system to achieve better error performance through iterative processing while maintaining reasonable implementation complexity through modular design.
3Loss of energy
If clipping is applied to reduce PAR, then power amplifier efficiency improves, but the transmitted signal quality deteriorates due to clipping error
Solution Approach 1:
The patent uses feedback by continuously forming clipping signals based on the residual signal and reference signal, and subtracting them iteratively. This feedback mechanism allows the system to maintain signal quality by compensating for clipping errors while achieving the necessary PAR reduction for improved power amplifier efficiency.
Solution Approach 2:
The patent creates a composite signal processing approach by combining the residual signal from the complex envelope clipper with the reference signal to form the clipping signal. This composite method allows the system to achieve both PAR reduction and maintained signal quality, resolving the contradiction between power amplifier efficiency and signal quality.
Data Source
AI summary
There is provided a method of clipping a transmission signal. The method comprises: providing a residual signal of a complex envelope clipper based on the transmission signal to be clipped; providing a reference signal respective to the residual signal, the reference signal corresponding to an ideal residual signal; forming a clipping signal on the basis of the residual signal and the reference signal; subtracting the clipping signal from the residual signal for removing higher amplitudes of the residual signal; and subtracting the clipping signal from the reference signal for providing a reference signal respective to the clipped residual signal.