Differential Feedback Mechanism for MU-MIMO Wireless Systems

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Solution Overview

Problem

Current wireless local area networks (WLANs) face challenges in achieving high data throughput while maintaining backward compatibility with legacy devices and managing excessive feedback overhead, which can negate the benefits of beamforming and reduce data transmission efficiency.

Innovation Solution

The implementation of differential feedback mechanisms in wireless communication systems, which utilize delta values of channel singular vectors and singular values to reduce feedback overhead, and the use of Huffman coding to optimize bit allocation based on probability distributions, allowing for reduced feedback frames and improved data throughput.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If full feedback methods are used to maintain beamforming performance, then channel state information accuracy is improved, but feedback overhead increases excessively

Engineering Contradiction:
Improvechannel state information accuracyVSAvoidfeedback overhead
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts and transmits only the essential differential information (changes in singular vectors and singular values) rather than the complete channel state information. By identifying and removing redundant feedback data, the system maintains beamforming accuracy while significantly reducing feedback overhead.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transforms the feedback approach by changing from absolute channel state parameters to differential parameters (changes relative to previous state). This parameter transformation allows the system to convey the same essential information with fewer bits, reducing overhead while preserving measurement precision.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If feedback overhead is reduced to improve data transmission efficiency, then productivity is improved, but channel state information accuracy deteriorates

Engineering Contradiction:
Improvedata transmission efficiencyVSAvoidchannel state information accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements a differential feedback mechanism where the receiver sends back only the changes in channel characteristics relative to the previous state. This feedback approach maintains sufficient accuracy for beamforming while minimizing the resources consumed by feedback transmission, thereby improving overall data transmission efficiency.

Inventive Principle:
Principle #23Feedback

3Loss of information

If traditional full feedback methods are used, then channel state information completeness is improved, but data throughput is reduced due to excessive overhead

Engineering Contradiction:
Improvechannel state information completenessVSAvoiddata throughput
Core Design Contradiction:
Loss of informationVSProductivity

Solution Approach 1:

The patent applies partial action by transmitting only the necessary portion of channel state information (the differential changes) rather than the complete set. This partial feedback approach provides sufficient information for effective beamforming while leaving out redundant data, thereby maximizing data throughput without significant loss of information completeness.

Inventive Principle:
Principle #16Partial or excessive action

4Productivity

If beamforming is implemented to increase data throughput, then productivity is improved, but feedback overhead increases

Engineering Contradiction:
Improvedata throughputVSAvoidfeedback overhead
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent extracts only the essential differential components of channel state information needed for beamforming operation. By removing redundant feedback elements and transmitting only the critical changes, the system enables beamforming to increase data throughput while keeping feedback overhead manageable.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS9831929B2Differential feedback within single user, multiple user, multiple access, and/or MIMO wireless communications
Publication Date: 2017.11.28 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD
  • US9831929B2 patent drawing
  • US9831929B2 patent drawing
  • US9831929B2 patent drawing

AI summary

Differential feedback within multiple user, multiple access, and/or MIMO wireless communications. After full feedback signal(s) have been received by a communication device (e.g., one that is to be performing beamforming for use in subsequent signal transmission), differential feedback signal(s) are received. Those differential feedback signal(s) are employed to update the full feedback signal(s) thereby generating updated/modified full feedback signals. Over time, such updated/modified full feedback signals may subsequently be further updated based upon later received inferential feedback signal(s). Such differential feedback signaling takes advantage of time and/or frequency correlation in a communication channel to provide for reduced feedback overhead by feeding back a difference or delta (Δ) relative to a previous value. For example, instead of providing full feedback signals in each respective/successive communication, feedback overhead is reduced by providing a difference or delta (Δ).