CSI Reporting Codebook Quantization for Wireless Overhead Reduction

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Solution Overview

Problem

Current wireless communication systems face challenges in efficiently reporting channel state information (CSI) due to high overhead and the need for sophisticated codebook designs that support increasing data traffic, higher data rates, and low latency in next-generation mobile communication systems.

Innovation Solution

A method for designing an efficient codebook and reporting CSI, which involves quantizing amplitude and phase coefficients differentially for each rank indicator/layer, using a subset of predefined sets and bitmaps, and transmitting bitmap information for enhanced Type II CSI reporting, while considering characteristics of channel transform methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional codebook design is used for CSI reporting, then implementation is simpler, but overhead increases and sophistication decreases

Engineering Contradiction:

Improvecodebook design complexityVSAvoidCSI reporting overhead

Core Design Contradiction:

Device complexityVSLoss of information

Solution Approach 1:

The codebook is segmented into multiple codebook groups, each corresponding to different channel conditions or transmission scenarios. This segmentation allows the system to select appropriate codebook groups based on channel state, reducing the overhead of reporting all possible codebook information while maintaining sophistication for different conditions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The codebook design is made dynamic by allowing selection among multiple codebook groups based on channel conditions. The system can adaptively choose which codebook group to use, making the complexity manageable through dynamic adaptation rather than static comprehensive design.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If sophisticated codebook design is implemented, then CSI accuracy improves, but overhead increases

Engineering Contradiction:

ImproveCSI accuracyVSAvoidreporting overhead

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

Different codebook groups are designed with different levels of sophistication tailored to specific local channel conditions. This allows high accuracy where needed while reducing overhead in conditions where simpler codebooks suffice, achieving local optimization of the accuracy-overhead tradeoff.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system changes parameters such as codebook group selection, quantization precision, and reporting frequency based on channel conditions. This dynamic parameter adjustment allows the system to maintain high CSI accuracy when channel conditions require it while reducing overhead when conditions permit.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If comprehensive CSI reporting is performed, then channel state accuracy improves, but latency increases

Engineering Contradiction:

Improvechannel state accuracyVSAvoidreporting latency

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

Instead of always performing comprehensive CSI reporting, the system applies partial action by reporting only the necessary codebook group information and allowing the receiver to infer or reconstruct complete CSI based on channel conditions and pre-agreed codebook structures. This reduces reporting latency while maintaining sufficient accuracy.

Inventive Principle:

Principle #16Partial or excessive action

4Measurement precision

If quantization precision is increased, then CSI accuracy improves, but overhead increases

Engineering Contradiction:

Improvequantization accuracyVSAvoidfeedback overhead

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

Codebook groups are pre-configured with different quantization precisions tailored to specific channel conditions or transmission scenarios. This preliminary preparation allows the system to select appropriate quantization precision levels without real-time computation, reducing overhead while maintaining accuracy where needed.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12170561B2Method state in wireless communication system, and device therefor

Publication Date: 2024.12.17 LG ELECTRONICS INC

AI summary

Disclosed in the present disclosure are a method for reporting channel state information (CSI) in a wireless communication system, and a device therefor. Specifically, a method for user equipment (UE) to report channel state information (CSI) in a wireless communication system comprises: a step for receiving CSI-related configuration information from a base station (BS); a step for receiving a reference signal from the base station; a step for calculating the CSI on the basis of the reference signal; and a step for transmitting the CSI to the base station. The step for calculating the CSI includes a step for quantizing a magnitude coefficient included in a matrix related to a codebook, a first set of reference amplitude and a second set of differential amplitude for the quantization of o the magnitude coefficient are predefined, and the magnitude coefficient may be quantized on the basis of a subset of (i) the first set and (ii) the second set.