Spatial-Domain Reception Parameter Alignment in MU-MIMO Signal Transmission

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Solution Overview

Problem

In Multiple User (MU) MIMO systems, the mismatch between channel estimations by the base station and user terminal leads to strong interference due to differences in precoding matrices, resulting in suboptimal signal reception.

Innovation Solution

The method involves the base station transmitting indication information for a spatial-domain reception parameter to the user terminal, allowing it to determine a matching spatial-domain reception parameter, thereby aligning the precoding matrices and reducing interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the user terminal independently determines the precoding matrix through channel estimation, then the user terminal can process received signals, but the mismatch between base station and user terminal channel estimation results causes strong interference

Engineering Contradiction:

Improveindependent signal processing capabilityVSAvoidmulti-user interference

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The base station feeds back spatial domain reception parameter indication information to the user terminal based on its channel estimation results. This feedback mechanism enables the user terminal to align its precoding matrix with the base station's equivalent channel, resolving the mismatch problem while maintaining independent processing capability

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The base station performs preliminary channel estimation and determines the appropriate spatial domain reception parameters before signal transmission. This preliminary action allows the base station to prepare the precoding information in advance, ensuring that the user terminal receives pre-configured parameters that eliminate interference before the actual data transmission occurs

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the base station and user terminal use different channel estimation results to determine precoding matrices, then each can independently process signals, but the precoding matrices do not match the equivalent channel

Engineering Contradiction:

Improveindependent processing reliabilityVSAvoidprecoding matrix matching precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent creates a common reference framework by having the base station determine spatial domain reception parameters based on its channel estimation and feed them back to the user terminal. This equipotential approach ensures both parties operate from the same channel state information, eliminating the precision mismatch while preserving independent processing

Inventive Principle:

Principle #12Equipotentiality

3Productivity

If the user terminal receives signals on multiple antenna ports, then more data streams can be received, but signals on non-indicated antenna ports contain strong interference

Engineering Contradiction:

Improvedata stream reception capacityVSAvoidinterference on non-indicated ports

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The base station indicates specific antenna ports that carry valid data streams for the user terminal. This local quality approach ensures that only the indicated antenna ports are processed by the user terminal, while non-indicated ports are ignored, thereby eliminating interference on those ports without reducing overall data reception capacity

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11510213B2Method for signal transmission, and corresponding user terminals and base stations

Publication Date: 2022.11.22 NTT DOCOMO INC

AI summary

Provided by the present disclosure are a method used for signal transmission, and corresponding user terminals and base stations. The method performed by a user terminal includes: receiving indication information for a spatial-domain reception parameter transmitted by a base station; determining a first spatial-domain reception parameter according to the indication information for a spatial-domain reception parameter, so that the user terminal receives downlink data signals through the first spatial domain reception parameter. The method performed by a base station includes: generating indication information for a spatial-domain reception parameter; and transmitting the indication information for a spatial-domain reception parameter to a user terminal, so that the user terminal determines a first spatial-domain reception parameter according to the indication information for a spatial-domain reception parameter.