MU-MIMO DCI Format for Interference Reduction

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Solution Overview

Problem

In Multi User-Multiple Input Multiple Output (MU-MIMO) wireless communication systems, existing technologies face challenges in efficiently providing and using control information, leading to interference between Mobile Stations (MS) due to the use of Dedicated Reference Signals (DRS) for data transmission.

Innovation Solution

Proposed revised formats for Downlink Control Information (DCI) that exclude the Transmitted Precoding Matrix Indicator (TPMI) field and introduce fields indicating the index of the DRS and the total number of DRSs, allowing MSs to differentiate between DRS and data REs, thereby reducing interference by precoding and mapping data on REs other than DRS locations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If Dedicated Reference Signals (DRS) are used for data transmission in MU-MIMO systems, then data transmission capacity is improved, but interference between Mobile Stations occurs due to overlapping resource elements

Engineering Contradiction:
Improvedata transmission capacityVSAvoidinterference between MSs
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the resource elements by clearly distinguishing DRS REs from data REs through revised DCI formats. The DCI indicates the total number of DRSs and their locations, allowing the MS to identify and separate DRS resource elements from data resource elements, thereby preventing interference while maintaining high data transmission capacity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by assigning different properties to different resource elements: DRS REs are designated for reference signal transmission with specific precoding, while other REs are allocated for data transmission. This localized differentiation ensures that DRS REs do not cause interference to data REs and vice versa, resolving the contradiction between transmission capacity and interference

Inventive Principle:
Principle #3Local quality

2Measurement precision

If DCI includes TPMI field for precoding control, then transmission precision is improved, but control information overhead increases

Engineering Contradiction:
Improveprecoding control precisionVSAvoidcontrol information overhead
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts the TPMI field from the DCI format, removing the need for explicit precoding matrix indication. Instead, the system uses the total number of DRSs indication and DRS location information to implicitly determine precoding, thereby reducing control information overhead while maintaining sufficient transmission precision through the resource element differentiation mechanism

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3787201B1Multi-user MIMO transmissions in wireless communication systems
Publication Date: 2024.10.09 SAMSUNG ELECTRONICS CO LTD
  • EP3787201B1 patent drawingFigure 1~2
  • EP3787201B1 patent drawingFigure 3
  • EP3787201B1 patent drawingFigure 4

AI summary

An apparatus and method for providing control information in a Multi User-Multiple Input Multiple Output (MU-MIMO) wireless communication system is provided. The method includes receiving a plurality of Resource Elements (REs) including Downlink Control Information (DCI), determining, using the DCI, a set of REs to which a plurality of Downlink Reference Signals (DRSs) may be mapped, determining remaining REs as REs to which data is mapped, and demodulating the data using a precoding vector of a DRS corresponding to the MS.