DMRS Resource Mapping for FD-OCC Overhead and Orphan REs

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Solution Overview

Problem

The introduction of eType1 and eType2 DMRS with higher order FD-OCC in Release 18 leads to increased overhead for indicating antenna ports, inefficient UE performance due to lack of co-scheduled UE information, and the presence of orphan REs, resulting in resource waste and confusion in identifying antenna ports.

Innovation Solution

Configuring UEs to handle eType1 and eType2 DMRS through control signaling that includes capability reports, indicating maximum antenna ports and orphan RE handling, and enabling eType1 and eType2 DMRS based on received control signaling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If eType1 and eType2 DMRS with higher order FD-OCC are introduced to support higher order MU-MIMO configurations, then the number of supported antenna ports increases, but the overhead for indicating antenna ports increases

Engineering Contradiction:

Improvenumber of supported antenna portsVSAvoidoverhead for indicating antenna ports

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent segments the antenna port indication into two parts: a first part indicating a first set of antenna ports and a second part indicating a second set of antenna ports. This segmentation allows the system to support higher order MU-MIMO configurations with more antenna ports while managing the indication overhead efficiently by dividing the indication process into manageable segments.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If FD-OCC-4 de-spreading is applied for every set of REs within a CDM group to support more antenna ports, then antenna port capacity increases, but orphan REs are created leading to resource waste

Engineering Contradiction:

Improveantenna port capacityVSAvoidresource waste from orphan REs

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent dynamically determines the FD-OCC de-spreading length based on the actual number of antenna ports being used. Instead of always applying FD-OCC-4, the system adjusts the de-spreading length to match the current configuration, thereby avoiding the creation of orphan REs and preventing resource waste while maintaining the ability to support high antenna port capacity when needed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the FD-OCC de-spreading length parameter based on the number of antenna ports in use. By dynamically adjusting this parameter rather than fixing it at FD-OCC-4, the patent eliminates orphan REs and optimizes resource utilization while still supporting higher order MU-MIMO configurations when required.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If UE applies maximum FD-OCC-4 de-spreading without knowing co-scheduled UE information, then antenna port identification is simplified, but UE efficiency decreases

Engineering Contradiction:

Improveantenna port identificationVSAvoidUE efficiency

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The patent implements feedback mechanisms where the UE receives information about the actual FD-OCC de-spreading length to be used from the network. This feedback allows the UE to adjust its de-spreading operation accordingly, maintaining ease of antenna port identification while improving efficiency by avoiding unnecessary maximum de-spreading when fewer antenna ports are actually in use.

Inventive Principle:

Principle #23Feedback

4Adaptability or versatility

If eType1 and eType2 DMRS are configured to support 16 and 24 antenna ports respectively, then MU-MIMO order increases, but system performance degrades due to overhead and orphan REs

Engineering Contradiction:

ImproveMU-MIMO orderVSAvoidsystem performance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent makes the DMRS configuration dynamic by allowing the network to indicate different FD-OCC de-spreading lengths and antenna port sets based on current system conditions. This dynamic configuration enables the system to support high MU-MIMO order when needed while avoiding the performance degradation caused by fixed maximum configurations, thereby maintaining reliability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes key parameters including FD-OCC de-spreading length, antenna port indication segments, and CDM group assignments based on the actual number of antenna ports being used. This parameter adaptation allows the system to achieve high MU-MIMO order support while preventing the overhead and orphan RE issues that would otherwise degrade system performance.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20260100795A1Method for demodulation reference signal configuration and resource mapping

Publication Date: 2026.04.09 GOOGLE LLC

AI summary

This disclosure provides systems, devices, apparatus, and methods, including computer programs encoded on storage media, for DMRS configuration. A UE receives (904) control signaling that causes the UE to enable at least one of: a number of eType1 or eType2 DMRS antenna ports, a minimal FD-OCC de-spreading length, or at least one orphan RE handling scheme. The UE receives (306) DCI that schedules a physical shared channel for at least one of: at least one indicated eType1/eType2 DMRS antenna port, an indicated FD-OCC de-spreading length, or an indicated orphan RE handling scheme. The UE communicates (911) with the network entity on the physical shared channel based on at least one of: the at least one indicated eType1/eType2 DMRS antenna port, the indicated FD-OCC de-spreading length, or the indicated orphan RE handling scheme.