Duplex Unit Single Antenna Interference Cancellation

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Solution Overview

Problem

Existing duplex units for microwave communication require multiple antennas to achieve simultaneous transmission and reception on overlapping frequency bands, which increases costs and is inefficient in terms of frequency spectrum usage.

Innovation Solution

A duplex unit comprising an interference canceller unit with a first adaptive filter and a duplex coupler, which splits and filters the transmit signal to suppress leakage, allowing for simultaneous transmission and reception on partly overlapping frequency bands using a single antenna by adapting the filter to make the interference-suppressed receive signal equal to the payload signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If frequency duplexing with separated transmit and receive frequency bands is used, then transmission and reception can be separated, but frequency spectrum usage becomes inefficient

Engineering Contradiction:
Improvesignal separationVSAvoidfrequency spectrum efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent changes the frequency parameter by allowing transmit and receive signals to operate on overlapping or identical frequency bands, eliminating the need for separated frequency bands and thereby improving frequency spectrum efficiency while maintaining signal separation through spatial and temporal filtering techniques

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If multiple antenna arrangements are used per transceiver, then simultaneous transmission and reception on overlapping frequency bands is enabled, but system cost increases

Engineering Contradiction:
Improveduplexing capabilityVSAvoidnumber of antennas
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent makes a single antenna arrangement perform multiple functions by enabling it to simultaneously handle both transmission and reception of microwave signals on overlapping frequency bands through the use of an interference canceller unit with adaptive filters, thereby eliminating the need for separate transmit and receive antenna arrangements

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces an interference canceller unit as an intermediary component between the antenna and the transceiver, which actively cancels out interference signals and enables full-duplex operation on a single antenna, thus avoiding the need for multiple antenna arrangements

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If a single antenna arrangement is used, then system cost is reduced, but simultaneous transmission and reception on overlapping frequency bands becomes difficult

Engineering Contradiction:
Improvenumber of antennasVSAvoidsimultaneous transmission and reception capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent employs dynamic adaptive filtering techniques where the interference canceller unit continuously adjusts its filter coefficients to track and cancel interference signals in real-time, enabling the single antenna system to dynamically adapt to changing transmission and reception conditions on overlapping frequency bands

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables efficient simultaneous transmission and reception of microwave signals on partly overlapping frequency bands using a single antenna, effectively suppressing interference and reducing the need for multiple antennas, thereby optimizing frequency spectrum usage and cost.

Implementation Method 1

The first adaptive filter is arranged to receive a second part of the transmit signal and to output a first filtered signal

Methodology Applied
Scientific EffectAdaptive filtering: Filter (electronic)

Data Source

PatentEP3011679B1A duplex unit
Publication Date: 2018.06.06 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3011679B1 patent drawingFigure 1
  • EP3011679B1 patent drawingFigure 2
  • EP3011679B1 patent drawingFigure 3

AI summary

A duplex unit (100) allowing simultaneous transmission and reception of microwave signals on at least partly overlapping frequency bands, comprising an interference canceller unit (140) and a control unit (180), the duplex unit (100) being arranged to receive a transmit signal (T1) and to output a first part of the transmit signal (T2) at an antenna port (121), the duplex unit (100) further being arranged to receive a receive signal (R1) comprising a payload signal at the antenna port (121), and to output a combination of the receive signal (R1) and a filtered transmit signal (T4) as an interference suppressed receive signal (R2) of the duplex unit (100).