Joint Decoding Engine for MIMO Signal Processing

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Solution Overview

Problem

Current wireless communication systems face challenges in efficiently decoding multiple-input multiple-output (MIMO) signals due to high computational complexity, which can lead to resource consumption and interference cancellation issues.

Innovation Solution

A joint decoding engine is employed in wireless devices to process MIMO signals using max log maximum a posteriori (MLM) processing, whitening, and successive interference cancellation (SIC), which involves determining symbol streams, scaling channel estimates, and performing MLM processing to produce decoded data streams efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional decoding methods are used for MIMO signals, then decoding can be performed, but computational complexity becomes excessively high

Engineering Contradiction:
Improvedecoding capabilityVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The joint decoding process is segmented into distinct functional modules: a whitening module that transforms the received signal to eliminate noise correlation, a max log MAP processing module that performs approximate maximum a posteriori decoding, and a de-rate matching module that adjusts the decoded stream to the original data rate. This segmentation allows each module to be optimized independently, reducing overall computational complexity while maintaining decoding reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs max log MAP processing as an approximation of the optimal but computationally prohibitive exact MAP decoding. This approximate method uses simplified calculations that are computationally cheaper and can be executed efficiently, sacrificing minimal decoding performance for significant reductions in computational burden.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Productivity

If signal processing techniques are added to improve communication quality, then communication efficiency improves, but device resources are consumed

Engineering Contradiction:
Improvecommunication efficiencyVSAvoiddevice resource consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent transforms the received MIMO signal through parameter changes in the whitening process, where the noise covariance matrix is computed and used to whiten the received signal. This parameter transformation simplifies subsequent decoding operations by eliminating noise correlation, thereby improving communication efficiency without proportionally increasing device resource consumption.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If multiple symbol streams are decoded separately, then processing is simpler, but interference cancellation is insufficient

Engineering Contradiction:
Improveprocessing simplicityVSAvoidinterference cancellation
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements joint decoding that merges the processing of multiple symbol streams into a unified decoding framework. The max log MAP processor simultaneously processes multiple streams while accounting for inter-stream interference, producing de-rate matched streams that have had interference effectively canceled. This merging approach maintains processing tractability while significantly improving interference cancellation compared to separate decoding.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2564535B1Using a joint decoding engine in a wireless device
Publication Date: 2019.06.19 QUALCOMM INC
  • EP2564535B1 patent drawingFigure 1
  • EP2564535B1 patent drawingFigure 2
  • EP2564535B1 patent drawingFigure 3

AI summary

A method for using a joint decoding engine in a wireless device is disclosed. A first symbol stream and a second symbol stream in a received multiple input multiple output (MIMO) signal is determined. A scaled channel estimate for a wireless transmission channel and a scaled noise covariance of the MIMO signal are also determined. The scaled channel estimate and the first symbol stream are whitened. Max log maximum a posteriori (MLM) processing is performed on the whitened first symbol stream to produce a first data stream. The first data stream may be de-rate matched and decoded to produce a decoded first data stream.