Precoding Matrix Switching for MIMO Reception Quality in LOS

Solution Overview

Problem

In multi-antenna communication systems, especially in Line-of-Sight (LOS) environments, the reception quality deteriorates as the Rician factor increases, leading to poor reception quality in spatial multiplexing MIMO systems used for broadcast or multicast communication, where existing methods fail to address this degradation without feedback information from communication partners.

Innovation Solution

A method involving the regular switching of precoding matrices to generate transmission signals, where adjacent symbols in the frequency and time domains are precoded with different or the same precoding matrices, improving reception quality by adapting to the LOS environment without requiring feedback information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If spatial multiplexing MIMO system is used to increase transmission speed, then productivity is improved, but reception quality deteriorates as Rician factor increases in LOS environment

Engineering Contradiction:

Improvetransmission speedVSAvoidreception quality

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system dynamically switches between different precoding methods (spatial multiplexing MIMO and single modulation signal transmission) based on the Rician factor detected in the propagation environment. When the Rician factor exceeds a threshold indicating LOS environment, the system switches to single modulation signal transmission with maximal ratio combining to maintain reception quality, otherwise uses spatial multiplexing MIMO for high transmission speed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the transmission parameter (precoding method) based on the propagation environment characteristics. By detecting the Rician factor and comparing it with a threshold, the system selects appropriate transmission parameters (spatial multiplexing vs. single signal with maximal ratio combining) to optimize both transmission speed and reception quality under different conditions.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If maximal ratio combining is used for single modulated signal transmission, then reception quality is improved in LOS environment, but transmission speed is limited compared to spatial multiplexing MIMO

Engineering Contradiction:

Improvereception qualityVSAvoidtransmission speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system dynamically switches between different precoding methods (spatial multiplexing MIMO and single modulation signal transmission) based on the Rician factor detected in the propagation environment. When the Rician factor exceeds a threshold indicating LOS environment, the system switches to single modulation signal transmission with maximal ratio combining to maintain reception quality, otherwise uses spatial multiplexing MIMO for high transmission speed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the transmission parameter (precoding method) based on the propagation environment characteristics. By detecting the Rician factor and comparing it with a threshold, the system selects appropriate transmission parameters (spatial multiplexing vs. single signal with maximal ratio combining) to optimize both transmission speed and reception quality under different conditions.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If spatial multiplexing MIMO system is used for broadcast or multicast communication, then service coverage is expanded, but reception quality deteriorates in LOS environment making service impossible despite high received electric field strength

Engineering Contradiction:

Improveservice coverageVSAvoidreception quality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system detects the Rician factor from the propagation environment as feedback information and uses this to determine the appropriate precoding method. By continuously monitoring the Rician factor and switching precoding methods based on this feedback, the system ensures reliable reception quality in broadcast and multicast communications across different environment types including LOS conditions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically switches between different precoding methods (spatial multiplexing MIMO and single modulation signal transmission) based on the Rician factor detected in the propagation environment. When the Rician factor exceeds a threshold indicating LOS environment, the system switches to single modulation signal transmission with maximal ratio combining to maintain reception quality, otherwise uses spatial multiplexing MIMO for high transmission speed.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11716127B2Transmission method, transmission apparatus, reception method and reception apparatus

Publication Date: 2023.08.01 SUN PATENT TRUST

AI summary

All data symbols used in data transmission of a modulated signal are precoded by hopping between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol in the frequency domain and the time domain all differ. A modulated signal with such data symbols arranged therein is transmitted.