Partial ML MIMO-DFE for Far End Crosstalk Mitigation

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Solution Overview

Problem

As data transmission rates in MIMO systems increase, FEXT noise becomes more significant due to higher operating frequencies, affecting the reliability of data transmission, and existing technologies struggle to effectively mitigate this noise in next-generation standards like 10GBASE-T.

Innovation Solution

A partial maximum likelihood (ML) far end crosstalk (FEXT) decoder is introduced, comprising an initial estimate generator module and a constellation point selector, which generates initial decisions based on filtered outputs and feedback from prior decisions, and selects constellation points to minimize mean squared error (MSE), using a scaling factor and feedback matrices to refine estimates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If data transmission rates and operating frequencies are increased, then bandwidth and data capacity are improved, but FEXT noise becomes more significant and transmission reliability deteriorates

Engineering Contradiction:
Improvedata transmission rateVSAvoidtransmission reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements a decision feedback equalizer (DFE) that uses feedback from previously decoded symbols to cancel FEXT noise. The feedback filter coefficients are updated based on detected errors, allowing the system to adaptively compensate for far end crosstalk at high frequencies and data rates

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically adjusts equalization parameters including feedback filter coefficients and decision thresholds based on channel conditions. By adapting these parameters in real-time, the system maintains optimal performance across varying frequency and data rate conditions while minimizing FEXT impact

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If full maximum likelihood decoding is used, then decoding accuracy is improved, but computational complexity increases

Engineering Contradiction:
Improvedecoding accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements partial maximum likelihood decoding that evaluates only the most likely constellation points rather than all possible points. This partial action approach maintains sufficient decoding accuracy for reliable communication while dramatically reducing the computational complexity compared to full ML decoding

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The decoding process is segmented into multiple stages: initial decision making based on simplified criteria, followed by refinement by evaluating only the P most likely constellation points. This segmentation allows the system to achieve accurate decoding without the full computational burden of exhaustive ML search

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS7542528B1Far end crosstalk mitigation in multiple-input multiple-output (MIMO) channels using partial maximum likelihood MIMO-DFE
Publication Date: 2009.06.02 MARVELL ASIA PTE LTD
  • US7542528B1 patent drawing
  • US7542528B1 patent drawing
  • US7542528B1 patent drawing

AI summary

A partial maximum likelihood (ML) far end crosstalk (FEXT) decoder for a multiple-input multiple-output (MIMO) communications channel comprises an initial estimate generator module that generates initial decisions for X channels based on filtered outputs of received signals and feedback from prior decisions. A constellation point selector selects P constellation points for the X channels from a constellation including N points based on the initial decisions. A current estimate generator module evaluates each of the selected P constellation points for each of the X channels as feedback signals and generates final decisions based on selected ones of the constellation points for each of the X channels.