Unequal DM-RS Positions for MIMO Channel Estimation

Solution Overview

Problem

Existing 5G NR specifications lack flexibility in choosing unequal density Demodulation Reference Signal (DM-RS) across time or frequency, failing to account for varying channel conditions experienced by different user equipment (UEs) in Multiple-Input Multiple-Output (MIMO) setups.

Innovation Solution

Implementing a system that allows for flexible DM-RS density configurations across frequency and time by introducing new parameters (dmrs.CDMGroupFrequencyDensity and dmrs.DMRSAdditionalPosition) to adjust DM-RS densities based on UE channel state information, position, and speed, enabling unequal density DM-RS across antenna ports.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If equal DM-RS densities are used for all antenna ports, then system complexity is reduced and implementation is simplified, but channel estimation accuracy deteriorates for user equipment experiencing different channel conditions

Engineering Contradiction:

Improvechannel estimation accuracyVSAvoidDM-RS configuration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by assigning different DM-RS densities to different antenna ports based on their specific channel conditions. Instead of using a uniform density for all ports, the system configures higher densities for ports experiencing NLOS or high mobility channels and lower densities for LOS channels, optimizing channel estimation accuracy for each local condition while managing overall system complexity through targeted adjustments.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by enabling dynamic configuration of DM-RS densities based on real-time channel state information, user equipment position, and mobility parameters. The system can adaptively adjust DM-RS densities in response to changing channel conditions, allowing the communication system to respond dynamically to varying propagation environments and optimize estimation accuracy under different operational scenarios.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If higher DM-RS densities are used, then channel estimation accuracy is improved, but resource utilization deteriorates due to increased overhead

Engineering Contradiction:

Improvechannel estimation accuracyVSAvoidresource utilization

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent applies local quality by assigning different DM-RS densities to different antenna ports based on their specific channel conditions. Instead of using a uniform density for all ports, the system configures higher densities for ports experiencing NLOS or high mobility channels and lower densities for LOS channels, optimizing channel estimation accuracy for each local condition while managing overall system complexity through targeted adjustments.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements parameter changes by dynamically adjusting DM-RS density parameters based on channel state information, user equipment position, and mobility parameters. The system can adaptively modify the density parameter for different antenna ports and communication scenarios, allowing optimization of the trade-off between estimation accuracy and resource utilization by changing parameters rather than following fixed configurations.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If fixed DM-RS densities are used, then system implementation is simplified, but adaptability to different propagation environments deteriorates

Engineering Contradiction:

Improveadaptability to channel conditionsVSAvoidDM-RS configuration complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamics by enabling dynamic configuration of DM-RS densities based on real-time channel state information, user equipment position, and mobility parameters. The system can adaptively adjust DM-RS densities in response to changing channel conditions, allowing the communication system to respond dynamically to varying propagation environments and optimize estimation accuracy under different operational scenarios.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by dynamically adjusting DM-RS density parameters based on channel state information, user equipment position, and mobility parameters. The system can adaptively modify the density parameter for different antenna ports and communication scenarios, allowing optimization of the trade-off between estimation accuracy and resource utilization by changing parameters rather than following fixed configurations.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12621098B2Unequal density demodulation reference signal positions

Publication Date: 2026.05.05 DELL PROD LP

AI summary

A system can facilitate first broadband cellular communications with a user equipment, wherein the first broadband cellular communications are configured to be communicated via a group of antenna ports. The system can determine to communicate the first broadband cellular communications according to a group of differing demodulation reference signal densities, wherein respective demodulation reference signal densities of the group of differing demodulation reference signal densities correspond to respective antenna ports of the group of antenna ports. The system can communicate the group of differing demodulation reference signal densities to the user equipment. The system can facilitate the first broadband cellular communications with the user equipment according to the group of differing demodulation reference signal densities.