DMRS Port Configuration via Extended CDM Groups

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Solution Overview

Problem

In future radio communication systems, such as NR, the method for increasing the number of DMRS ports beyond existing specifications has not been actively studied, which can lead to deteriorated communication throughput and quality if an appropriate number of DMRS ports is not used.

Innovation Solution

A terminal that includes a receiving section for receiving downlink control information containing a resource assignment of a physical uplink shared channel and an antenna port indication value, and a control section that controls the transmission of a demodulation reference signal (DMRS) based on an association between the value, the number of code division multiplexing (CDM) groups, and a DMRS port, with the number of CDM groups for DMRS configuration type 1 being larger than 2 and for type 2 being larger than 3.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the number of DMRS ports is increased beyond existing specifications, then communication throughput and quality are improved, but the system complexity and lack of standardized methods worsen

Engineering Contradiction:

Improvecommunication throughputVSAvoidsystem complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent changes the parameter of CDM group numbering from the conventional 0-1 range to an extended range (0-N-1 where N>2 for type 1 and N>3 for type 2). This parameter change enables support for more DMRS ports (up to 8 for type 1 and up to 12 for type 2) while maintaining compatibility with existing DMRS structures and processing methods.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent segments the DMRS port space by introducing additional CDM groups. Instead of using a single CDM group or limited groups, the system divides the resource into multiple CDM groups (0, 1, 2, ..., N-1), each capable of supporting multiple DMRS ports through code division multiplexing. This segmentation allows systematic expansion of DMRS port capacity.

Inventive Principle:

Principle #1Segmentation

2Quantity of substance

If the number of CDM groups is increased to support more DMRS ports, then the number of multiplexed users is improved, but the configuration complexity increases

Engineering Contradiction:

Improvenumber of multiplexed usersVSAvoidconfiguration complexity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The extended CDM group numbering scheme provides a universal framework that can accommodate different numbers of DMRS ports and multiplexing scenarios. The same basic structure (CDM groups with multiple ports each) serves multiple functions: supporting more users, maintaining backward compatibility, and enabling flexible resource allocation without requiring separate configuration mechanisms for different scenarios.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20250119256A1Terminal, radio communication method, and base station

Publication Date: 2025.04.10 NTT DOCOMO INC

AI summary

A terminal according to one aspect of the present disclosure includes a receiving section that receives downlink control information including a resource assignment of a physical uplink shared channel and a value of an antenna port indication, and a control section that controls transmission of a demodulation reference signal (DMRS), based on an association between the value, the number of code division multiplexing (CDM) groups, and a DMRS port. The number of the CDM groups for DMRS configuration type 1 is larger than 2, and the number of the CDM groups for DMRS configuration type 2 is larger than 3. According to one aspect of the present disclosure, an appropriate number of DMRS ports can be used.