MIMO Precoding Matrix Selection via Layer Power Product

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Solution Overview

Problem

Current MIMO communication systems face performance degradation in low SINR and practical rank regions due to suboptimal precoding matrix selection, which can be affected by errors and delays, and require complex calculations that are difficult to implement at the receiver.

Innovation Solution

A method for selecting a precoding matrix that minimizes the product of powers of received layers, avoiding matrix inversions and applicable for both low and high SINR values, integrated with Adaptive Modulation and Coding (AMC) state selection to enhance throughput and avoid performance degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional precoding matrix selection methods are used, then performance is maintained in high SINR regions, but performance degrades in low SINR and practical rank regions

Engineering Contradiction:
Improveperformance in low SINR regionsVSAvoidcalculation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the selection criterion parameter from conventional metrics (such as SINR per layer or total capacity) to the product of powers of received layers. This parameter transformation enables the selection function to inherently prioritize balancing power distribution across layers, which naturally improves performance in low SINR and practical rank conditions without requiring additional complex computations or system modifications.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If precise precoding matrix selection is implemented, then system performance is optimized, but the system becomes more sensitive to errors and delays in feedback

Engineering Contradiction:
Improvesystem throughputVSAvoidrobustness against errors and delays
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies beforehand cushioning by designing a selection criterion that is inherently more robust to feedback errors and delays. The product of powers metric provides a smoother, more stable selection basis compared to conventional metrics, creating a buffer against the adverse effects of imperfect feedback information. This cushioning effect maintains system productivity even when feedback contains errors or delays.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If complex selection functions are used, then performance is maximized, but implementation at the receiver becomes difficult

Engineering Contradiction:
Improveperformance optimizationVSAvoidease of implementation at receiver
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent substitutes complex matrix operations (mechanical computational system) with a simpler power product calculation. Instead of requiring matrix inversions, eigenvalue computations, or other complex linear algebra operations, the selection function only needs to compute the product of powers of received layer signals. This substitution maintains performance optimization while dramatically simplifying the computational burden at the receiver.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP2520033B1Method for selecting a precodlng matrix in a "multiple input multiple output" ("MIMO") system
Publication Date: 2018.03.07 TELECOM ITALIA SPA
  • EP2520033B1 patent drawingFigure 1
  • EP2520033B1 patent drawingFigure 2A~2B
  • EP2520033B1 patent drawingFigure 3

AI summary

A method for selecting a precoding matrix to be used in a MIMO communication system (100) comprising a transmitter (105), a receiver (115) and a communication channel (110), wherein the precoding matrix is used by the transmitter to precode codewords to be transmitted to the receiver over the communication channel. At the receiver, an optimum precoding matrix within a codebook of precoding matrices is determined on the base of a metric related to the power of received signal layers. An indication is then fed back from the receiver to the transmitter useful to enable the transmitter to select the optimum precoding matrix from the codebook.