Artificial Channel Processing for CDM Correlation and PAPR Reduction

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Solution Overview

Problem

The issue of increased peak-to-average power ratio (PAPR) in 3GPP NR release 15 due to strong correlation between CDM groups in DMRS symbols, which requires more headroom and linearity in RF circuits, is addressed.

Innovation Solution

Applying an artificial channel effect to the layers prior to combining them, which is designed to remove correlation between CDM groups and is removed at the receiver side during channel estimation/equalization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If CDM groups are used for multiplexing in 3GPP NR release 15, then spectral efficiency and multiplexing capability are improved, but peak-to-average power ratio (PAPR) increases significantly

Engineering Contradiction:

Improvespectral efficiencyVSAvoidpeak-to-average power ratio

Core Design Contradiction:

ProductivityVSPower

Solution Approach 1:

The patent applies artificial channel effects that modify the signal parameters of CDM groups before combining them. By introducing controlled channel characteristics (such as frequency-selective fading patterns) through parameter transformation in the frequency domain, the signal peaks are reduced while maintaining the multiplexing capability. This changes the statistical properties of the composite signal to reduce PAPR.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces an artificial channel effect as an intermediary processing step between the CDM group generation and the final signal combining. This intermediary layer (the artificial channel) transforms the correlated CDM group signals into less correlated signals with reduced peak power, acting as a mediator that enables both high spectral efficiency and reduced PAPR.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Power

If artificial channel effect is applied to remove correlation between CDM groups, then PAPR is reduced, but device complexity increases

Engineering Contradiction:

Improvepeak-to-average power ratioVSAvoidsignal processing complexity

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The artificial channel effect is implemented through parameter transformations in the frequency domain, specifically applying channel-like filtering operations. By using standard signal processing techniques (convolution with channel impulse response or multiplication with channel frequency response), the correlation between CDM groups is reduced with computationally efficient operations that fit within existing baseband processing capabilities.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The artificial channel effect is applied preliminarily to the CDM group signals before they are combined and transmitted. This preliminary processing removes the correlation issue proactively, preventing the need for more complex corrective measures later in the transmission chain or at the receiver end.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12432105B2PAPR reduction for correlated CDM groups

Publication Date: 2025.09.30 INTEL CORP

AI summary

An apparatus can include baseband processing circuitry to generate at least one artificial channel function for combining with at least one multiple-input multiple-output (MIMO) layer input to a precoder. The baseband processing circuitry can also provide the combined artificial channel function and MIMO layer input to the precoder. The apparatus can also include circuitry to transmit a channel based on the combined artificial channel function and MIMO layer input. Other systems and methods are also described.