Peak Suppression Device Using Band Pass Filter for PAPR Reduction
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Solution Overview
Problem
In wireless communication, amplifiers experience reduced power efficiency when handling signals with high peak-to-average power ratio (PAPR), such as OFDM signals, due to the need for large backoff, which degrades signal quality and increases noise levels.
Innovation Solution
A peak suppression device comprising a suppression-signal generating unit and a band pass filter that attenuates out-band frequency components, reducing PAPR by adding frequency components that suppress peak amplitudes and filtering out unwanted frequencies, thereby improving power efficiency and signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If clipping is applied to suppress peak amplitudes in the transmission signal, then the PAPR is reduced and amplifier power efficiency is improved, but out-band frequency components are generated that degrade signal quality
Solution Approach 1:
The invention extracts and removes out-band frequency components from the clipped signal using a band limiting filter. The filter selectively eliminates frequency components outside the transmission band while preserving the in-band components that carry the actual transmission information, thereby resolving the contradiction between peak suppression and signal quality maintenance.
Solution Approach 2:
The band limiting filter acts as an intermediary between the clipping operation and the amplifier. It processes the clipped signal to remove harmful out-band components before amplification, mediating between the peak suppression requirement and the signal quality requirement.
2Loss of energy
If frequency components are added to suppress peaks, then PAPR is reduced, but signal quality degrades due to noise introduction
Solution Approach 1:
The band limiting filter extracts and removes the noise components (out-band frequency components) from the signal. By eliminating these unwanted frequency components, the filter preserves signal quality while allowing the peak suppression mechanism to function effectively in improving amplifier efficiency.
3Reliability
If large backoff is taken in the amplifier to handle high PAPR signals, then signal distortion is reduced, but power efficiency deteriorates
Solution Approach 1:
The invention performs preliminary peak suppression and out-band component removal before the signal enters the amplifier. By pre-processing the signal to reduce PAPR and eliminate harmful frequency components, the amplifier can operate with smaller backoff and higher efficiency while maintaining signal quality.
Solution Approach 2:
The invention converts the harmful effect of clipping (generation of out-band components) into a beneficial process. By intentionally clipping the signal and then systematically removing the resulting out-band components through filtering, the system achieves both peak suppression and signal quality maintenance, enabling efficient amplifier operation.
Data Source
AI summary
A peak suppression device includes a suppression-signal generating unit and a band pass filter (BPF). The suppression-signal generating unit generates a suppression signal that is obtained by adding, to a transmission signal, a frequency component in which components of frequencies from a boundary of a band of the transmission signal to a frequency that is away therefrom toward an out-band of the transmission signal by predetermined frequencies are attenuated, out of frequency components of a signal to suppress a peak of the transmission signal. The BPF attenuates, after the suppression signal is amplified by the amplifier, a frequency component outside the band of the transmission signal in the amplified suppression signal.