Terminal DMRS Port Allocation With Extended FD-OCC for Throughput

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Solution Overview

Problem

Future radio communication systems require an increased number of DMRS ports to maintain communication throughput and quality, but existing methods to achieve this are inadequate, leading to potential deterioration in communication quality and throughput.

Innovation Solution

A terminal and base station that utilize a frequency domain orthogonal cover code (FD-OCC) longer than 2 to manage DMRS ports, allowing for appropriate allocation of antenna ports for downlink shared channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the number of DMRS ports is increased to meet future radio communication system requirements, then communication throughput and quality can be maintained, but existing allocation methods become inadequate leading to resource management complexity

Engineering Contradiction:
Improvecommunication throughputVSAvoidDMRS port allocation complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by modifying the FD-OCC length from the conventional value of 2 to a longer value (e.g., 4 or 6). This parameter change enables more antenna ports to be multiplexed within the same CDM group, thereby increasing the total number of available DMRS ports without requiring additional CDM groups or frequency resources. The terminal determines the FD-OCC length based on higher-layer signaling or pre-agreed rules, and uses this extended parameter to allocate DMRS ports for multiple terminals, resolving the contradiction between maintaining throughput and managing allocation complexity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If an appropriate number of DMRS ports is allocated to multiple terminals, then communication quality is maintained, but improper allocation leads to deterioration in communication throughput and quality

Engineering Contradiction:
Improvecommunication qualityVSAvoidcommunication throughput
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements feedback mechanisms where the terminal determines whether remaining antenna ports in CDM groups are allocated to downlink shared channels for other terminals based on higher-layer signaling or pre-agreed rules. This feedback loop ensures that DMRS port allocation is dynamically adjusted according to actual system conditions, allowing the base station to properly allocate ports to multiple terminals without interference. The terminal's determination process provides feedback information that helps maintain communication quality while optimizing throughput by preventing improper port allocation.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4589857A1Terminal, wireless communication method, and base station
Publication Date: 2025.07.23 NTT DOCOMO INC
  • EP4589857A1 patent drawingFigure 1
  • EP4589857A1 patent drawingFigure 2
  • EP4589857A1 patent drawingFigure 3A~3D

AI summary

A terminal according to an aspect of the present disclosure includes a receiving section that receives an indication of one or more antenna ports in one or more code division multiplexing (CDM) groups for a demodulation reference signal (DMRS) to which a frequency domain orthogonal cover code (FD-OCC) longer than 2 is applied, and a control section that determines, based on the indication, whether to assume that a remaining antenna port of the one or more antenna ports in the one or more CDM groups is allocated to transmission of a downlink shared channel to another terminal. According to an aspect of the present disclosure, it is possible to use an appropriate number of DMRS ports.