Beamforming Codebook Segmentation for Bandwidth Reduction

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Solution Overview

Problem

Conventional wireless communication systems face high bandwidth consumption when transmitting channel covariance matrices or beamforming matrices from mobile stations to base stations, which can divert resources away from data traffic.

Innovation Solution

The use of a base codebook and a differential codebook to efficiently generate and quantify beamforming matrices, where the mobile station transmits codewords representing the quantized beamforming and difference matrices, allowing the base station to estimate the original beamforming matrix, thereby reducing bandwidth usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the mobile station transmits the channel covariance matrix or beamforming matrix to the base station, then the beamforming accuracy is improved, but the bandwidth consumption increases

Engineering Contradiction:
Improvebeamforming accuracyVSAvoidbandwidth consumption
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The codebook is segmented into a base codebook containing representative beamforming matrices and a differential codebook containing correction matrices. The mobile station transmits only indices selecting from these segmented codebooks rather than transmitting full beamforming matrices, thereby reducing feedback bandwidth while maintaining beamforming accuracy through the combined base and differential selection mechanism.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If a single codebook is used for beamforming quantization, then the device complexity is reduced, but the quantization error increases

Engineering Contradiction:
Improvecodebook structureVSAvoidquantization error
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The codebook is divided into a base codebook and a differential codebook. The base codebook provides coarse quantization with lower complexity, while the differential codebook provides fine-grained corrections. This segmentation allows the system to achieve lower quantization error by combining selections from both codebooks without proportionally increasing device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The differential codebook acts as an intermediary that bridges the gap between the limited representation of the base codebook and the desired high-precision beamforming matrix. By selecting correction matrices from the differential codebook based on the base codebook selection, the system achieves higher precision without directly transmitting full-precision matrices.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3145142B1Beamforming using base and differential codebooks
Publication Date: 2020.08.26 APPLE INC
  • EP3145142B1 patent drawingFigure 1
  • EP3145142B1 patent drawingFigure 2
  • EP3145142B1 patent drawingFigure 3

AI summary

Embodiments of methods and apparatus for determining and/or quantizing a beamforming matrix are disclosed. In some embodiments, the determining and/or quantizing of the beamforming matrix may include the use of a base codebook and a differential codebook. Additional variants and embodiments are also disclosed.