MIMO Channel Matrix Segmentation for CSI Feedback

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Solution Overview

Problem

In MIMO network wireless communication systems, existing methods are limited in transmitting complete downlink channel state information (CSI) due to the constraint of limited feedback information, which hampers the maximization of system transmission capacity.

Innovation Solution

The method efficiently combines long-term and short-term feedback information by dividing the downlink MIMO channel matrix into a long-term eigen matrix, a short-term gain matrix, and an output matrix, and quantizes these components for transmission through separate feedback channels, allowing for the restoration of complete CSI at the transmitter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If complete downlink CSI is transmitted to the transmitter, then system transmission capacity is maximized, but the amount of feedback information required exceeds channel limitations

Engineering Contradiction:

Improvesystem transmission capacityVSAvoidamount of feedback information

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The downlink MIMO channel matrix is divided into two distinct components: long-term channel information (slowly varying) and short-term channel information (rapidly varying). This segmentation allows each component to be handled differently in the feedback process, reducing the total feedback burden while preserving complete CSI for transmitter processing

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The long-term channel information is extracted and fed back to the transmitter in advance, before the short-term channel variations occur. This preliminary action allows the transmitter to have prior knowledge of the slowly varying channel characteristics, reducing the need to feed back complete instantaneous CSI

Inventive Principle:

Principle #10Preliminary action

2Loss of information

If long-term and short-term feedback information are combined efficiently, then complete CSI can be transmitted, but the feedback channel load must be managed

Engineering Contradiction:

Improvecompleteness of CSIVSAvoidfeedback channel structure

Core Design Contradiction:

Loss of informationVSDevice complexity

Solution Approach 1:

The feedback channel is organized into two distinct dimensions: a long-term feedback channel for slowly varying channel components and a short-term feedback channel for rapidly varying components. This dimensional separation allows complete CSI to be transmitted without overwhelming a single feedback channel

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS11190240B2Method and apparatus for sending and receiving channel state information in multiple-input multiple-output network wireless communication systems

Publication Date: 2021.11.30 SAMSUNG ELECTRONICS CO LTD

AI summary

A method and an apparatus are provided for transmitting channel state information (CSI) by a terminal in a communication system. The method includes receiving a first signal from a first serving cell; receiving a second signal from a second serving cell; calculating first CSI for the first serving cell based on the first signal; calculating second CSI for the first serving cell based on the first signal; calculating first CSI for the second serving cell based on the second signal; calculating second CSI for the second serving cell based on the second signal; transmitting the first CSI and the second CSI for the first serving cell respectively; and transmitting the first CSI and the second CSI for the second serving cell respectively.