5G NR In-Band Predistortion Compensation for Spectrum Ripple
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Solution Overview
Problem
Existing 5G test instruments face challenges in achieving wide instantaneous bandwidth, leading to poor in-band spectrum ripple and phase consistency due to device and board inconsistencies, which are difficult to correct and require time-consuming debugging.
Innovation Solution
A method for predistortion compensation processing of 5G NR in-band modulated signals involves configuring a modulator to output a continuous wave signal, measuring power differences, generating a compensated channel impulse response, and applying a power compensation factor to the baseband signals to improve spectral flatness and phase consistency without modifying device circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hardware device circuits are modified to correct in-band spectrum ripple and phase consistency, then signal quality improves, but device complexity and debugging time increase
Solution Approach 1:
The patent replaces hardware circuit modification with digital signal processing. Instead of physically adjusting device circuits to correct in-band spectrum ripple and phase consistency, the invention uses predistortion compensation algorithms that process signals in the digital domain. This substitution of mechanical/hardware adjustment with digital processing resolves the contradiction by maintaining signal quality improvement while eliminating complex hardware modifications and their associated debugging requirements
Solution Approach 2:
The patent changes the approach from modifying hardware parameters to adjusting digital signal parameters. By measuring the actual channel response and applying predistortion compensation through digital signal processing, the system corrects in-band spectrum ripple and phase consistency by changing signal characteristics rather than hardware characteristics, thereby avoiding device complexity increases
2Manufacturing precision
If each PCB board is debugged separately to achieve signal quality improvement, then manufacturing precision improves, but productivity decreases
Solution Approach 1:
The patent creates a universal predistortion compensation solution that can be applied across multiple PCB boards without individual debugging. By measuring the channel response once and generating a compensation filter that works across different boards, the system achieves manufacturing precision improvement while eliminating time-consuming separate debugging processes, thereby resolving the productivity contradiction
Solution Approach 2:
The patent performs preliminary measurement and compensation filter generation before actual signal transmission. By pre-measuring the channel response and pre-calculating the predistortion compensation parameters, the system eliminates the need for repeated debugging during production, thus improving both manufacturing precision and productivity by performing the corrective action in advance
Data Source
AI summary
A method for realizing predistortion compensation processing for 5G NR in-band modulated signals includes configuring the modulator to output a continuous wave signal, switch the output frequency interval of the signal to be consistent with the 5G NR subcarrier bandwidth, and record the power value P0 corresponding to the current frequency through the power meter. The power measurement difference between all points and P0 is calculated and performs normalization, and generates a compensated channel impulse response after shaping filtering; converts it into a power compensation factor in the time domain; performs inverse Fourier transform to generate I and Q baseband signals; generates compensated baseband data; the generated baseband data is filtered, and an analog zero intermediate frequency signal is generated, which is input to the broadband demodulator for frequency conversion modulation of the 5G NR broadband signal. The method operates without the need to modify the device circuit in the channel.