Duo-Binary Transceiver FFE Adaptation for Channel ISI

Solution Overview

Problem

High data rate communication systems using duo-binary modulation face challenges from inter-symbol interference (ISI) due to frequency-dependent channel attenuation, which existing feed-forward equalization methods have not adequately addressed.

Innovation Solution

Adaptive channel equalization is achieved by selectively processing information from either the upper or lower eye of a received duo-binary signal to determine updated coefficients for the feed-forward equalizer (FFE) at the transmitter, using a backchannel to transmit these coefficients, and implementing a 1+Z−1 filter response combining transmitter FFE and channel ISI.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If feed-forward equalization (FFE) is used at the transmitter to address inter-symbol interference (ISI), then signal quality is improved, but equalization complexity and power consumption at the receiver increase

Engineering Contradiction:

Improvesignal qualityVSAvoidequalization complexity at receiver

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent inverts the conventional equalization approach by moving the FFE from the receiver to the transmitter. Instead of equalizing the received signal at the receiver, the transmitter applies FFE to pre-compensate for channel distortion, thereby improving signal quality while reducing receiver complexity.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent implements adaptive feedback mechanisms where the receiver measures channel characteristics and feeds back information to the transmitter, enabling the transmitter to dynamically adjust its FFE coefficients to optimize signal quality while maintaining low receiver complexity.

Inventive Principle:

Principle #23Feedback

2Reliability

If feed-forward equalization (FFE) is used at the transmitter to address inter-symbol interference (ISI), then signal quality is improved, but power consumption at the receiver increases

Engineering Contradiction:

Improvesignal qualityVSAvoidpower consumption at receiver

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent inverts the conventional equalization approach by moving the FFE from the receiver to the transmitter. Instead of equalizing the received signal at the receiver, the transmitter applies FFE to pre-compensate for channel distortion, thereby improving signal quality while reducing receiver complexity.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent implements adaptive feedback mechanisms where the receiver measures channel characteristics and feeds back information to the transmitter, enabling the transmitter to dynamically adjust its FFE coefficients to optimize signal quality while maintaining low receiver complexity.

Inventive Principle:

Principle #23Feedback

3Productivity

If duo-binary modulation is used for high data rate communication, then spectral efficiency is improved, but sensitivity to cross-talk increases

Engineering Contradiction:

Improvedata rateVSAvoidcross-talk sensitivity

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the modulation parameters by using duo-binary modulation with three signal levels instead of four-level PAM4, thereby achieving similar spectral efficiency while reducing cross-talk sensitivity through the specific characteristics of duo-binary signaling.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary equalization at the transmitter before signal transmission, pre-compensating for channel effects and cross-talk interference, which reduces the impact of these harmful factors on the received signal quality.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12355596B2Adaptive channel equalization for a duo-binary transceiver

Publication Date: 2025.07.08 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

Systems and methods related for duo-binary transceivers with adaptive channel equalization are described. An example method for adapting a channel between a first duo-binary transceiver and a second duo-binary transceiver, different from the first duo-binary transceiver, where the transmitter includes a feed-forward equalizer (FFE), is described. The method includes, at a receiver associated with the second duo-binary transceiver, selectively processing information at a given time from only an upper eye or a lower eye of a received duo-binary signal to determine updated coefficients for the feed-forward equalizer (FFE) of the transmitter associated with the first duo-binary transceiver. The method further includes using a backchannel between the transmitter and the receiver, sending the updated coefficients to the transmitter. The method further includes transmitting duo-binary signals that are equalized using the updated coefficients for the FFE of the transmitter associated with the first duo-binary transceiver.