DMRS Sequence Allocation for Multi-User Multiplexing

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Solution Overview

Problem

Current wireless communication systems face challenges in achieving multi-user multiplexing for terminal devices using different multiple access modes, as the number of terminal devices that can obtain orthogonality using orthogonal codes is limited, and existing methods do not effectively support diverse multiple access modes for DMRS sequences.

Innovation Solution

A method where a terminal device determines the quantity and physical resource allocation of DMRS sequences based on the multiple access mode used, allowing DMRS sequences to occupy different sub-carriers in the same frequency domain bandwidth, enabling orthogonality through different cyclic shifts, even when using different multiple access modes such as DFT-S-OFDM and CP-OFDM.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If orthogonal codes are used to obtain orthogonality for multi-user multiplexing, then orthogonality between different terminal devices is achieved, but the number of terminal devices that can be supported is small

Engineering Contradiction:
ImproveorthogonalityVSAvoidnumber of terminal devices
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent segments the frequency domain bandwidth into multiple sub-carrier groups, where each group is assigned to a different DMRS sequence. This allows multiple terminal devices to occupy different sub-carrier groups simultaneously, thereby increasing the number of supported devices while maintaining orthogonality through frequency domain separation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from relying solely on code domain orthogonality to incorporating frequency domain resource allocation. By introducing sub-carrier group differentiation as an additional dimension, the system can support more terminal devices beyond the limitations of orthogonal code capacity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If different multiple access modes (DFT-S-OFDM and CP-OFDM) are used for uplink transmission, then transmission flexibility is improved, but multi-user multiplexing between different access modes becomes difficult to realize

Engineering Contradiction:
Improvemultiple access mode flexibilityVSAvoidmulti-user multiplexing complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent creates a universal resource allocation framework that works across both DFT-S-OFDM and CP-OFDM access modes. By defining a common method for determining DMRS sequence quantity and sub-carrier occupation based on multiple access mode indicators, the system achieves multi-functionality that supports diverse access modes within a unified multiplexing structure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent dynamically adjusts DMRS configuration parameters (sequence quantity K, sub-carrier occupation patterns) based on the multiple access mode indicator. This parameter adaptation allows the system to optimize DMRS resource allocation for each access mode while maintaining compatible multiplexing rules, thereby reducing overall system complexity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3573396B1Radio communication method, terminal device, and network device
Publication Date: 2022.10.05 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD
  • EP3573396B1 patent drawingFigure 1
  • EP3573396B1 patent drawingFigure 2
  • EP3573396B1 patent drawingFigure 3~4

AI summary

A wireless communication method, a terminal device and a network device can realize multi-user multiplexing of terminal devices that transmit DMRS sequences using different multiple access modes. The method includes: determining, by a terminal device, a quantity K of demodulation reference signal DMRS sequences corresponding to a first DMRS port and a physical resource occupied by each DMRS sequence in the K DMRS sequences, where K is a positive integer; and sending, on the determined physical resource occupied by the each DMRS sequence, the each DMRS sequence to a network device using the first DMRS port.