Wireless Node Self-Interference Cancellation with Symmetric Preambles

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Solution Overview

Problem

In-band full-duplex communication systems face challenges in decoding received signals due to self-interference created by simultaneous transmission and reception, with existing suppression techniques limiting their application and requiring accurate self-interference channel estimation.

Innovation Solution

A method and system that utilizes a set of symmetric preambles in the received signal to eliminate the self-interference channel estimate, employing an adaptive filter to determine and cancel the self-interference signal, allowing for effective decoding of the received signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If in-band full-duplex communication is implemented for simultaneous transmission and reception, then communication efficiency is improved, but self-interference degrades signal decoding

Engineering Contradiction:
Improvecommunication efficiencyVSAvoidself-interference
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent uses the transmitted signal itself (the source of self-interference) to generate an estimate of the self-interference channel. By processing the known transmitted signal through the self-interference channel estimate, the system creates a cancellation signal that removes the harmful self-interference from the received signal, thereby enabling simultaneous transmission and reception

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If existing self-interference suppression techniques are used, then some self-interference cancellation is achieved, but application scope is limited and accurate channel estimation is required

Engineering Contradiction:
Improveself-interference suppressionVSAvoidapplication scope
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system performs self-service by using its own transmitted signal to estimate the self-interference channel and generate the cancellation signal. This self-contained approach does not require external calibration signals or complex coordinated procedures with other nodes, making the technique more universally applicable across different wireless communication scenarios

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3593456B1Method and system for cancelling self-interference by a node in a wireless communication system
Publication Date: 2025.08.13 INDIAN INST OF TECH MADRAS
  • EP3593456B1 patent drawingFigure 1
  • EP3593456B1 patent drawingFigure 2A~2B
  • EP3593456B1 patent drawingFigure 3A~3B

AI summary

Embodiments herein provide a method for decoding received signal by node in wireless communication system. The method includes receiving a signal from a first User Equipment (UE), where the received signal comprises a set of preambles in which each preamble is identical to an at least one preamble in a preamble structure and obtaining a composite signal comprising a self- interference signal, where the self-interference signal is known at the node. Further, the method includes determining self-interference channel estimate using the composite signal and decoding the received signal by eliminating the self-interference signal from the received signal based on the self- interference channel estimate.