CSI Matrix Scaling and Quantization for Wireless Reporting

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Solution Overview

Problem

The computational complexity and power consumption associated with generating channel state information (CSI) matrices in wireless communications systems are high, especially when handling large bandwidths and multiple spatial streams, leading to increased latency and implementation challenges in CSI reporting.

Innovation Solution

The method involves scaling each value in the CSI matrix using a power-of-two value based on a determined maximum value, followed by quantization and transmission, which reduces computational complexity and includes additional information like received signal strength indicators and total gain in the CSI report to improve RF sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If CSI matrices are generated for each subcarrier across large bandwidths and multiple spatial streams, then measurement precision and channel state information accuracy are improved, but computational complexity and power consumption increase significantly

Engineering Contradiction:
Improvechannel state information accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the CSI matrix generation process by applying codebook-based quantization to represent channel states using predefined codebook entries rather than computing full complex matrices for each subcarrier. This segmentation reduces the computational burden while maintaining essential channel state information accuracy through selective codebook index reporting.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the representation parameters of CSI from full complex matrix values to quantized codebook indices and associated amplitude/phase adjustments. This parameter transformation reduces the data processing complexity and power consumption while preserving the critical channel state information needed for MIMO operations.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If full-precision CSI matrices are computed and reported for each subcarrier, then channel state information accuracy is improved, but latency and processing time increase

Engineering Contradiction:
Improvechannel state information accuracyVSAvoidlatency
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts only the essential components of CSI information by separating the channel state representation into codebook index selection and amplitude/phase adjustment parameters. This extraction approach eliminates redundant computational steps and reduces the time required to generate and report CSI while maintaining sufficient accuracy for effective MIMO communication.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies preliminary quantization and codebook matching operations before full CSI matrix computation and reporting. By pre-defining codebook entries and using them as reference points for channel state representation, the system reduces processing time and latency in generating CSI reports across multiple subcarriers and spatial streams.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If detailed CSI matrices are generated across multiple spatial streams and subcarriers, then RF sensing capability is improved, but power consumption increases

Engineering Contradiction:
ImproveRF sensing capabilityVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent segments the RF sensing measurement process by using codebook-based quantization to represent channel states across multiple spatial streams and subcarriers. This segmentation allows the system to maintain detailed RF sensing capability through selective codebook index reporting and associated parameters while significantly reducing the power consumption associated with computing and processing full-precision CSI matrices for all subcarriers and streams.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS12132682B2Scaling and quantization for channel state information reporting
Publication Date: 2024.10.29 QUALCOMM INC
  • US12132682B2 patent drawing
  • US12132682B2 patent drawing
  • US12132682B2 patent drawing

AI summary

Methods, systems, and devices for wireless communications are described. A station (STA) may receive a null data packet (NDP) on a plurality of subcarriers, and the STA may generate a channel state information (CSI) matrix for each subcarrier of the plurality of subcarriers. After generating a CSI matrix for a subcarrier, such as at least one subcarrier, the STA may scale each value in the CSI matrix using a power-of-two value to minimize complexity. Specifically, instead of scaling each value in the CSI matrix to a value between zero and one using divisions (for example, which may be computationally expensive), the STA may use shifting to scale each value in the CSI matrix. The STA may then quantize the scaled values in the CSI matrix for reporting, and the STA may transmit the quantized, scaled values in the CSI matrix in a CSI report.