Waveform Compression Using Multistage Shaping for PAPR and ACLR
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wireless communication systems face challenges in increasing the transmission range of signals without adversely affecting peak-to-average power ratio (PAPR), adjacent channel leakage ratio (ACLR), and in-band emissions (IBE), which can result in undesirable waveform properties.
Innovation Solution
A multistage waveform shaping process involving an interference cancellation operation and a clipping operation in the first stage, followed by frequency selective filtering in the second stage, to enhance in-band emissions and reduce PAPR and ACLR, respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the output of a power amplifier is increased to extend signal range, then the transmission distance is improved, but the waveform properties deteriorate (increased PAPR, ACLR, and in-band emissions)
Solution Approach 1:
The waveform shaping process is divided into multiple stages: a first stage performing interference cancellation and clipping operations, and a second stage performing frequency selective filtering. This segmentation allows each stage to address specific waveform quality issues independently, enabling the system to achieve acceptable waveform properties at higher amplifier output levels
Solution Approach 2:
Waveform shaping operations are performed before power amplification to pre-condition the signal. By applying interference cancellation, clipping, and filtering operations in advance, the signal is prepared to withstand higher amplification levels without generating excessive distortion, intermodulation products, or spectral leakage
2Reliability
If waveform shaping operations are applied to improve signal quality, then PAPR and ACLR are reduced, but the complexity of the transmission system increases
Solution Approach 1:
The waveform shaping function is segmented into distinct processing stages with specific purposes: interference cancellation for reducing intermodulation distortion, clipping for controlling peak power, and frequency selective filtering for managing spectral leakage. This modular approach allows for optimized implementation of each function while maintaining overall system manageability
Solution Approach 2:
The system dynamically adjusts waveform shaping parameters such as clipping thresholds and filter characteristics based on operating conditions. This allows the complexity of processing to be adapted to the specific requirements of each transmission scenario, reducing unnecessary computational burden while maintaining signal quality
3Reliability
If interference cancellation and clipping operations are performed, then in-band emissions are improved and PAPR is reduced, but adjacent channel leakage increases
Solution Approach 1:
The waveform shaping process separates in-band emission control from adjacent channel leakage management by using different techniques in sequence: interference cancellation and clipping for in-band emissions, followed by frequency selective filtering for adjacent channel leakage. This segmented approach addresses each issue systematically
Solution Approach 2:
Frequency selective filtering acts as an intermediary operation between the first stage (interference cancellation and clipping) and the final transmission. It mediates the transition by selectively attenuating frequency components that cause adjacent channel leakage while preserving the benefits of the previous stage's in-band emission improvements
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may generate an input signal including information for transmission over a wireless channel. The UE may perform a first waveform shaping stage on the input signal to increase an in-band emissions ratio and reduce a peak-to-average power ratio (PAPR) of the input signal. The UE may perform a second waveform shaping stage on the output of the first waveform shaping stage to reduce an adjacent channel leakage ratio of the output of the first waveform shaping stage. The UE may then transmit a signal over the wireless channel based on an output of the second waveform shaping stage.