RF Front-End Cancellation for Full-Duplex Self-Interference

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Solution Overview

Problem

Full duplex radio technology faces diminished data throughput due to self-interference from the system's own transmission, which interferes with its own reception.

Innovation Solution

The implementation of a transceiver with a main transmitter, a canceller transmitter, a main receiver, and a canceller receiver, along with an RF front-end system that includes main and canceller power amplifiers, allows for the generation and amplification of RF cancellation signals to counteract self-interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If full duplex radio technology uses the same frequency for continuously transmitting and receiving, then spectral efficiency is doubled, but self-interference from the system's own transmission interferes with its own reception, diminishing data throughput

Engineering Contradiction:

Improvespectral efficiencyVSAvoidself-interference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful self-interference signal into a useful cancellation reference by capturing a portion of the transmit signal before it causes interference, then using this captured signal to generate an equal and opposite cancellation signal that actively neutralizes the interference at the receiver

Inventive Principle:

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

Solution Approach 2:

The system dynamically adjusts parameters of the cancellation signal including gain, phase, and timing to match the interfering transmit signal characteristics, enabling effective cancellation across varying operational conditions

Inventive Principle:

Principle #35Parameter changes

2Productivity

If a transceiver with main and canceller transmitters and receivers is implemented to cancel self-interference, then data throughput is improved, but device complexity increases

Engineering Contradiction:

Improvedata throughputVSAvoidtransceiver structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The transceiver is segmented into functionally independent main and canceller paths, where the canceller path is a simplified copy of the main path that processes only the interference cancellation function, allowing modular design and independent optimization of each path

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The canceller transmitter and receiver components serve multiple functions: they generate cancellation signals for self-interference suppression, provide reference signals for channel estimation, and enable the system to operate in both full-duplex and half-duplex modes flexibly

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20250293719A1Apparatus and methods for self-jamming cancellation in full duplex radios

Publication Date: 2025.09.18 ANALOG DEVICES INT UNLTD CO

AI summary

Apparatus and methods for self-jamming cancellation in full duplex radios are disclosed herein. In certain embodiments, an RF front-end system includes a main power amplifier that amplifies an RF transmit signal from a main transmitter of a transceiver and a canceller power amplifier that amplifies an RF cancellation signal from a canceller transmitter of the transceiver. The RF front-end system operates to split the amplified RF cancellation signal into two or more cancellation signals including a first cancellation signal that is combined with an RF receive signal and a second cancellation signal that is combined with a sensed transmit signal from an output of the main power amplifier. The RF receive signal and the first cancellation signal are combined and provided to a main receiver of the transceiver, while the sensed transmit signal and the second cancellation signal are combined and provided to a canceller receiver of the transceiver.