DMRS Sequence Selection for Nonlinear PUSCH Compensation
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Solution Overview
Problem
The use of a Zadoff-Chu (ZC) sequence for DMRS in DFT-s-OFDM results in low peak-to-average power ratio (PAPR), leading to inaccurate nonlinear estimation and poor compensation accuracy due to the PA's nonlinear distortion, affecting EVM and ACLR performance.
Innovation Solution
Employing a pseudo-random sequence, such as a Gold sequence, with a higher PAPR as the DMRS, ensuring the PA operates in a more nonlinear region for improved nonlinear estimation and compensation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a ZC sequence is used as DMRS for DFT-s-OFDM, then the PAPR is low, but the nonlinear estimation accuracy is poor
Solution Approach 1:
The patent changes the PAPR parameter of the DMRS sequence by switching from a ZC sequence (low PAPR) to a Gold sequence (high PAPR). This parameter change enables the PA to operate in a more nonlinear region, generating sufficient nonlinear distortion for accurate nonlinear estimation and compensation.
2Object-generated harmful factors
If the PA operates in a linear region, then signal distortion is low, but nonlinear compensation accuracy is insufficient
Solution Approach 1:
The patent converts the harmful nonlinear distortion generated by high-PAPR Gold sequence DMRS into a beneficial effect. The intentional introduction of nonlinear distortion through high-PAPR sequences provides sufficient signal for accurate nonlinear estimation, which is then used to compensate for PA nonlinearities and improve overall compensation accuracy.
Data Source
AI summary
This application provides a nonlinear compensation method and an apparatus. A terminal device receives first indication information from a network device, where the first indication information indicates that a demodulation reference signal (DMRS) sequence includes a sequence whose peak to average power ratio (PAPR) is higher than that of a Zadoff-Chu (ZC) sequence. The terminal device sends the sequence and data to the network device, where the data is carried on a physical uplink shared channel (PUSCH). A nonlinear estimation result of the sequence is used by the network device to perform nonlinear compensation on the PUSCH. The sequence and the data are transmitted by using a discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) waveform.