Selective Peak Cancellation for Higher ADC Dynamic Range
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Solution Overview
Problem
Analog to digital converters (ADCs) in communication devices face limitations in dynamic range due to high peak to average power ratio (PAPR) signals, leading to noise and distortion, especially in full duplex systems where echoes from transmitted signals mask received signals, and existing solutions like pre-cancellation DACs increase cost and power consumption without always providing significant performance gains.
Innovation Solution
Implementing a Peak Amplitude Separation element that evaluates signal amplitudes and applies a reference threshold to a pre-cancellation DAC, allowing only amplitudes above the threshold to be processed, thereby reducing PAPR and improving ADC dynamic range without adding significant noise, using a simple and low-power DAC configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pre-cancellation DAC is used to reduce PAPR, then ADC dynamic range is improved, but device complexity and power consumption increase
Solution Approach 1:
The invention segments the PAPR reduction task by introducing a Peak Amplitude Separation element that divides the signal processing into two paths: one for peak detection and one for normal signal processing. Only peaks exceeding a threshold are processed by the pre-cancellation DAC, reducing overall system complexity while maintaining ADC dynamic range improvements.
Solution Approach 2:
The invention applies local quality by making the pre-cancellation DAC operate selectively only when peak amplitudes exceed a threshold, rather than continuously processing all signals. This localized operation reduces power consumption and complexity while maintaining the benefits where needed.
2Measurement precision
If pre-cancellation DAC processes all signal amplitudes, then PAPR is reduced, but noise is added to the signal
Solution Approach 1:
The invention applies partial action by having the pre-cancellation DAC process only the necessary portion of the signal - specifically, only peak amplitudes exceeding a threshold. This selective processing avoids adding noise to normal signal levels while still achieving PAPR reduction where needed.
Solution Approach 2:
The invention extracts only the problematic peak components from the signal for processing by the pre-cancellation DAC, while leaving the rest of the signal untouched. This extraction approach prevents noise addition to the majority of the signal that doesn't require PAPR reduction.
3Measurement precision
If reference threshold is set low, then more peaks are canceled improving dynamic range, but more noise is introduced
Solution Approach 1:
The invention uses parameter changes by dynamically adjusting the reference threshold based on signal conditions and optimizing it to achieve the desired balance between PAPR reduction and noise introduction. The threshold parameter is tuned to cancel only significant peaks while avoiding noise introduction from excessive cancellation.
4Productivity
If full duplex operation is implemented, then communication efficiency is improved, but received signals are masked by transmitted signal echoes
Solution Approach 1:
The invention applies preliminary anti-action by using the pre-cancellation DAC to reduce PAPR in transmitted signals before they are sent. This preliminary processing reduces the amplitude of potential echo peaks, thereby reducing the masking effect on received signals in full duplex operation while maintaining communication efficiency.
Data Source
AI summary
Increasing an analog to digital converter (ADC) dynamic range for a communications device. In the communications device, a reference threshold is established for a peak to average power ratio (PAPR) improvement factor for RF signals received by the communications device. A digital to analog converter (DAC) adjustment factor is established for a DAC to account for inaccuracies of a pre-cancellation DAC and fine tuning of an analog gain of received RF signals. A peak amplitude separation element evaluates an absolute value of a portion of a particular RF signal against the reference threshold. Upon the peak amplitude separation element determining that the portion is smaller than the reference threshold, the element assigns a zero value to a DAC signal current sample; otherwise, the element assigns a quantized value of the sample to the DAC signal current sample, used in adjusting a post-cancellation signal sample.