DM-RS Configuration for DCI Payload Reduction in Wireless Systems

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Solution Overview

Problem

Current wireless communication systems face challenges in efficiently transmitting and receiving dedicated demodulation reference signals (DM-RSs), particularly in defining optimal Downlink Control Information (DCI) formats based on the number of symbols mapped, multiplexing methods, and channel state information, which affects payload size and overhead.

Innovation Solution

A method and apparatus that define DCI formats differently depending on the number of symbols to which DM-RSs are mapped, restrict multiplexing methods among antenna ports, and use a Rank Indicator to limit codebook subsets, thereby reducing payload size and overhead, and configure DM-RS for efficient reception of Physical Downlink Shared Channel (PDSCH) signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If DCI format is defined with detailed DM-RS configuration parameters, then DM-RS transmission flexibility is improved, but payload size of DCI field increases

Engineering Contradiction:
ImproveDM-RS transmission flexibilityVSAvoidpayload size of DCI field
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The DCI format is segmented into multiple fields with different configurations based on the number of DM-RS symbols (1 or 2 symbols). This segmentation allows the system to transmit only the necessary configuration parameters for the current scenario, reducing unnecessary payload while maintaining flexibility when needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The DCI format dynamically adapts its structure based on the DM-RS symbol count. When 1 symbol is used, a compact format is applied; when 2 symbols are used, an extended format with additional parameters is applied. This dynamic adaptation ensures payload size matches the actual configuration needs.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If multiple multiplexing methods are supported among antenna ports, then system versatility is improved, but DCI overhead increases

Engineering Contradiction:
Improvemultiplexing method supportVSAvoidDCI overhead
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

Different multiplexing methods are applied to different antenna port groups based on local requirements. The patent restricts and configures multiplexing methods specifically for each antenna port group rather than applying a universal complex configuration, thereby reducing overall DCI overhead while maintaining necessary versatility.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If Rank Indicator defines more codebook subsets, then channel state information precision is improved, but payload size increases

Engineering Contradiction:
Improvechannel state information precisionVSAvoidpayload size
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The Rank Indicator defines codebook subsets selectively rather than exhaustively covering all possible subsets. The patent applies partial action by configuring only the necessary codebook subsets based on current channel conditions and requirements, achieving sufficient precision without the overhead of defining all possible subsets.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3506545B1Method for transmitting and receiving reference signal in wireless communication system and device therefor
Publication Date: 2024.09.04 LG ELECTRONICS INC
  • EP3506545B1 patent drawingFigure 1(a)~1(b)
  • EP3506545B1 patent drawingFigure 2
  • EP3506545B1 patent drawingFigure 3

AI summary

Disclosed is a method and apparatus for transmitting and receiving a Reference Signal (RS) performed by a User Equipment (UE) in a wireless communication system. According to the present invention, a method and apparatus includes receiving a first Dedicated Demodulation Reference Signal and a first Physical Downlink Shared Channel (PDSCH); receiving a Physical Downlink Control Channel (PDCCH) including Downlink Control Information (DCI) in relation to a configuration of the second Dedicated Demodulation Reference Signal based on the first PDSCH; and receiving the second Dedicated Demodulation Reference Signal and a second PDSCH based on the PDCCH, and the first Dedicated Demodulation Reference Signal is transmitted only on a single antenna port, and a configuration of the DCI is determined based on the maximum number of symbols to which the second Dedicated Demodulation Reference Signal is mapped.