Pulse Cancellation Crest Factor Reduction Low Sampling Rate
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Solution Overview
Problem
Conventional peak-cancellation crest factor reduction (PC-CFR) systems require high sampling rates, which increase data path complexity and resource usage, limiting their efficiency in reducing peak-to-average power ratio (PAR) for multi-carrier signals, especially in wireless communications.
Innovation Solution
A method and apparatus that utilize a sampling frequency between the bandwidth frequency and twice the bandwidth frequency, with interpolation of samples proximate to signal peaks to apply a cancellation pulse, reducing the signal peak while maintaining accuracy and efficiency, and employing a windowed crest factor reduction block for post-processing to enhance peak cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high sampling rate (3x-5x of bandwidth frequency) is used for accurate peak detection and cancellation, then peak detection accuracy is improved, but data path complexity and resource requirements increase
Solution Approach 1:
The patent changes the sampling rate parameter from the conventional 3x-5x of bandwidth frequency to approximately 1x bandwidth frequency. This parameter change reduces data path complexity and resource requirements while maintaining peak detection accuracy through adaptive processing techniques and interpolation methods that reconstruct peak information from lower-rate samples.
Solution Approach 2:
Instead of uniformly processing all samples at high rate, the patent applies partial action by identifying and processing only the regions containing peaks at the lower sampling rate. This selective processing approach maintains accuracy for critical peak detection while reducing overall computational complexity and resource usage.
2Manufacturing precision
If a high sampling rate is used for cancellation pulse generation, then cancellation accuracy is improved, but resource usage and processing complexity increase
Solution Approach 1:
The patent changes the operating parameter of the cancellation pulse generator from high sampling rate (3x-5x bandwidth) to low sampling rate (approximately 1x bandwidth). This parameter change reduces resource usage significantly while maintaining cancellation accuracy through adaptive pulse shaping and timing adjustment techniques that compensate for the lower sampling rate.
Solution Approach 2:
The patent uses interpolation and reconstruction techniques to create accurate peak representations from lower-rate samples. This copying approach allows the system to work with fewer samples while still achieving the necessary precision for accurate cancellation pulse generation and application.
3Quantity of substance
If the sampling rate is reduced below 3x bandwidth frequency, then resource requirements are reduced, but peak detection accuracy may deteriorate
Solution Approach 1:
The patent employs feedback mechanisms where the system continuously monitors the effectiveness of peak cancellation and adjusts processing parameters accordingly. This feedback allows the system to maintain high peak detection accuracy even at reduced sampling rates by adapting to the actual signal characteristics and cancellation results.
Solution Approach 2:
The patent performs preliminary identification of peak regions using the lower-rate samples, then applies more sophisticated processing and interpolation techniques specifically in those identified regions. This preliminary action approach ensures that computational resources are focused where they are most needed, maintaining accuracy while reducing overall resource requirements.
Data Source
AI summary
A method relates generally to data transmission. In such a method, a peak detector detects a signal peak of an input signal exceeding a threshold amplitude. This detecting includes sampling the input signal at a sampling frequency to provide a sampled signal. The sampling frequency is in a range greater than a bandwidth frequency of a carrier signal used for providing the input signal and less than twice the bandwidth frequency. Samples of the sampled signal proximate to the signal peak are interpolated to provide a reconstructed peak. A cancellation pulse is applied by a cancellation pulse generator to the samples to reduce the signal peak. A version of the input signal is output after application of the cancellation pulse.