Transceiver Front-End Isolation Using Frequency-Translated Impedance

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Solution Overview

Problem

Current transceiver front-ends for frequency division duplex communication devices face challenges in providing effective isolation between the transmitter and receiver due to interference, with existing solutions being expensive, bulky, and requiring multiple components for different frequency bands, and existing on-chip isolation methods being complex and power-intensive.

Innovation Solution

The implementation of a transceiver front-end with transmit and receive frequency blocking arrangements using networks of passive components, including transformers and frequency translated impedances, which block specific frequency intervals to isolate signals, allowing for tunable and integrated solutions that avoid power loss and impedance matching complexities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If off-chip acoustic wave duplex filters are used to provide isolation between transmitter and receiver, then isolation performance is improved, but device size, cost, and complexity increase

Engineering Contradiction:
Improveisolation performanceVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the isolation function from bulky off-chip acoustic wave duplex filters and implements it using compact on-chip cancellation circuits. The harmful interference signal is separated and canceled electronically rather than using physical filtering components, thereby reducing device size and complexity while maintaining isolation performance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/acoustic wave-based duplex filter system with an electronic cancellation system using circuits and signal processing. This substitution eliminates the need for physical acoustic wave components, reducing device size, cost, and complexity while achieving the same isolation function through electrical means.

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

2Adaptability or versatility

If multiple duplexers are used to support several frequency bands, then frequency band support is improved, but device size and cost increase

Engineering Contradiction:
Improvefrequency band supportVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a universal isolation circuit that can operate across multiple frequency bands using a single configuration. The cancellation circuit is designed to be frequency-agile and can adapt to different operating bands without requiring separate duplexers for each band, thereby supporting multiple frequency bands while reducing device size and complexity.

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

Solution Approach 2:

The patent employs dynamic frequency tuning capabilities in the cancellation circuit, allowing the isolation mechanism to adapt its operating frequency according to the current band being used. This dynamic adjustment enables a single circuit to serve multiple frequency bands, eliminating the need for multiple static duplexers.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If on-chip cancellation circuits are used for isolation, then device size is reduced, but power consumption and circuit complexity increase

Engineering Contradiction:
Improvedevice sizeVSAvoidpower consumption
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The patent designs the cancellation circuit to automatically track and cancel interference signals without requiring external control or adjustment. The circuit self-adjusts its parameters to maintain optimal cancellation performance across frequency changes, reducing the need for additional control circuitry and minimizing power consumption while maintaining compact size.

Inventive Principle:
Principle #25Self-service

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

This approach provides efficient and tunable isolation between the transmitter and receiver, reducing power consumption and eliminating the need for complex impedance tracking, while supporting multiple frequency bands with a simplified and area-efficient design.

Implementation Method 1

The transmit frequency blocking arrangement has a blocking frequency interval associated with the transmit frequency and a non-blocking frequency interval associated with the receive frequency

Methodology Applied
Scientific EffectFrequency selective impedance: Filter (electronic)

Implementation Method 2

The receive frequency blocking arrangement has a blocking frequency interval associated with the receive frequency and a non-blocking frequency interval associated with the transmit frequency

Methodology Applied
Scientific EffectFrequency selective impedance: Filter (electronic)

Implementation Method 3

At least one of the transmit frequency blocking arrangement and the receive frequency blocking arrangement comprises a network of passive components comprising at least one transformer

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2870700B1Transceiver front-end
Publication Date: 2017.06.28 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2870700B1 patent drawingFigure 1~3b
  • EP2870700B1 patent drawingFigure 4~5
  • EP2870700B1 patent drawingFigure 6~7

AI summary

A transceiver front-end of a communication device is disclosed. The transceiver front-end is connectable to a signal transmission and reception arrangement adapted to transmit a transmit signal having a transmit frequency and to receive a receive signal having a receive frequency, to a transmitter adapted to produce the transmit signal, and to a receiver adapted to process the receive signal. The transceiver front-end comprises at least one of a transmit frequency blocking arrangement and a receive frequency blocking arrangement. The transmit frequency blocking arrangement has a blocking frequency interval associated with the transmit frequency and a non-blocking frequency interval associated with the receive frequency, and is adapted to block passage of transmit frequency signals between the signal transmission and reception arrangement and the receiver. The receive frequency blocking arrangement has a blocking frequency interval associated with the receive frequency and a non-blocking frequency interval associated with the transmit frequency, and is adapted to block passage of receive frequency signals between the signal transmission and reception arrangement and the transmitter. At least one of the transmit frequency blocking arrangement and the receive frequency blocking arrangement comprises a network of passive components comprising at least one transformer and a frequency translated impedance adapted to have a higher impedance value in the blocking frequency interval than in the non- blocking frequency interval.