Waveform Mirroring for PAPR Reduction in Wireless Transmitters
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Solution Overview
Problem
Wireless communication systems face challenges with high peak-to-average power ratio (PAPR) in waveforms, leading to non-linear distortion and reduced signal quality, particularly in high sub-THz bands where conventional methods like clipping and filtering are not completely invertible and inefficient.
Innovation Solution
The method involves reducing the peak amplitude of waveforms by mirroring the peak portions across a mirror level, using a reduction function based on the difference between the mirror level and the peak, and then inverting the mirrored portions at the receiving end to restore the original waveform, thereby reducing PAPR and minimizing distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional clipping and filtering methods are used to reduce peak amplitude, then PAPR is reduced, but the method is not completely invertible and causes signal distortion
Solution Approach 1:
The patent applies inversion by mirroring the peak portion of the waveform across a mirror level to create a reduced peak amplitude waveform. At the receiver, the mirrored portion is inverted back to restore the original peak, making the process completely invertible unlike conventional clipping methods. This resolves the contradiction by reducing PAPR through mirroring while maintaining signal quality through invertible transformation.
Solution Approach 2:
The patent creates a mirrored copy of the peak waveform portion and places it below the mirror level, rather than directly clipping the peak. This copying approach preserves the original waveform structure while creating a reducible peak, enabling both PAPR reduction and perfect reconstruction at the receiver, thus resolving the signal quality deterioration issue.
2Use of energy by moving object
If peak amplitude is reduced to lower PAPR, then power efficiency improves, but signal distortion and adjacent leakage increase
Solution Approach 1:
By using mirroring followed by inversion at the receiver, the patent achieves power efficiency through PAPR reduction without permanent signal distortion. The invertible nature ensures that the mirrored peak can be perfectly reconstructed, eliminating the harmful distortion effects that would otherwise accompany peak reduction.
Solution Approach 2:
The patent converts the potentially harmful peak amplitude into a beneficial mirrored structure below the mirror level. This transformation reduces PAPR and improves power efficiency while the mirrored portion serves as a recoverable artifact rather than permanent distortion, turning what would be harmful into a reversible intermediate state.
3Manufacturing precision
If mirroring is used to reduce peak amplitude, then PAPR is reduced and signal quality is maintained, but out-of-band emission occurs
Solution Approach 1:
The mirror level acts as an intermediary reference that enables the mirroring operation. By using this intermediate reference level, the patent can reduce peak amplitude while maintaining signal quality, though the mirroring process itself generates out-of-band emission as a side effect of the waveform transformation.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a transmitting device may generate a waveform having an original amplitude. The transmitting device may reduce a peak portion of the original amplitude that is above a mirror level according to a reduction function that is based at least in part on a difference function associated with a difference between the mirror level and the peak portion, to obtain a reduced peak amplitude for the waveform. The transmitting device may transmit the waveform with the reduced peak amplitude. Numerous other aspects are described.