DMRS Sequence Design for Interference Cancellation

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Solution Overview

Problem

In wireless communication networks, inefficient transmission of reference signals by neighboring base stations hampers the estimation of transmission characteristics by user equipment (UE), leading to suboptimal interference cancellation, especially as demand for mobile broadband access increases and networks become more congested.

Innovation Solution

The method involves determining and transmitting demodulation reference signal (DMRS) sequences and location patterns by base stations based on specific transmission characteristics, allowing user equipment to accurately identify and cancel interference from neighboring cells by minimizing cross-correlation and using orthogonal sequences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If reference signals are transmitted by neighboring base stations, then user equipment can estimate transmission characteristics for interference cancellation, but inefficient reference signal transmission degrades estimation accuracy and cancellation performance

Engineering Contradiction:
Improveestimation accuracyVSAvoidinterference cancellation efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies parameter changes by modifying reference signal transmission parameters including sequence selection, resource element mapping patterns, and cyclic shifts. These parameter variations enable user equipment to accurately estimate transmission characteristics of neighboring base stations, thereby improving both measurement precision and interference cancellation efficiency in congested networks

Inventive Principle:
Principle #35Parameter changes

2Productivity

If more user equipments access the network to meet growing demand, then mobile broadband access capacity increases, but network congestion increases and interference worsens

Engineering Contradiction:
Improvenetwork capacityVSAvoidinterference level
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent implements local quality by enabling user equipment to perform cell-specific interference cancellation for neighboring base stations. This allows each UE to adaptively estimate and cancel interference from specific neighboring cells based on local transmission characteristics, thereby maintaining network capacity while mitigating the harmful effects of interference in congested environments

Inventive Principle:
Principle #3Local quality

3Reliability

If reference signals are transmitted efficiently, then user equipment can accurately identify and cancel interference from neighboring cells, but current reference signal transmission is inefficient

Engineering Contradiction:
Improveinterference cancellation performanceVSAvoidreference signal transmission complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by enabling flexible and adaptive reference signal transmission where base stations can dynamically select sequences, resource element mappings, and transmission parameters based on network conditions. This dynamic approach improves interference cancellation reliability while managing transmission complexity through standardized yet adaptable signal designs

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3583733B1Methods and apparatus for reference signal design for interference cancellation
Publication Date: 2023.09.20 QUALCOMM INC
  • EP3583733B1 patent drawingFigure 1
  • EP3583733B1 patent drawingFigure 2
  • EP3583733B1 patent drawingFigure 3

AI summary

Methods and apparatus for reference signal design are provided. In some aspects, a base station determines one or more of: a demodulation reference signal (DMRS) sequence or a DMRS location pattern, based: on at least one of a plurality of transmission characteristics, and transmits one or more of the determined DMRS sequence or the determined OMRS location pattern. In further aspects, a user equipment identifies one or more of: a demodulation reference signal (DMRS) sequence or a DMRS location pattern from a base station, determines at least one of a plurality of transmission characteristics of the first base station based on one or more of: the identified DMRS sequence, or the identified DMRS location pattern, and performs interference cancellation for transmissions from the base station.