Self-Interference Canceller With Q-Enhanced RF Delay Cells

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Solution Overview

Problem

Frequency division duplex communication systems face challenges in achieving full-duplex operation due to transmitter interference in the receiver, which is exacerbated by the limited isolation provided by diplexers, leading to complex filter designs and increased power consumption.

Innovation Solution

A self-interference canceller using Q-enhanced delay cells and FIR filters is employed to synthesize nanosecond delays at RF frequencies, mimicking the leakage channel response to generate a replica signal that cancels out self-interference, thereby enhancing isolation and reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If diplexer is used to suppress transmitter interference, then isolation is improved, but device complexity increases due to nanosecond delay requirements at RF

Engineering Contradiction:

Improvetransmitter interferenceVSAvoidfilter design complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces complex RF domain filter designs with nanosecond delay requirements with a baseband digital signal processing approach. By moving the interference cancellation function from the RF domain to the baseband domain, the system avoids the need for complex high-order filters while achieving the same isolation effect through digital signal processing of the transmitted signal replica.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If higher order filters are used to achieve large isolation with smaller frequency separation, then isolation is improved, but device complexity increases

Engineering Contradiction:

Improvetransmitter interferenceVSAvoidfilter order

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent substitutes complex high-order RF filters with a baseband digital processing system that generates and subtracts a replica of the transmitted signal. This approach achieves the same interference suppression effect without requiring high-order filters, thereby reducing device complexity while maintaining isolation performance.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Object-affected harmful factors

If active cancellation technique is used in RF domain, then isolation is improved, but power consumption increases

Engineering Contradiction:

Improvetransmitter interferenceVSAvoidpower consumption

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent replaces power-consuming RF domain active cancellation circuits with a baseband digital signal processing implementation. By performing the cancellation operation at baseband where digital processing is more energy-efficient, the system achieves the same interference suppression with lower power consumption.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS12431937B2Self-interference canceller

Publication Date: 2025.09.30 INTEL CORP

AI summary

A transceiver may include a transmit path and a receive path that are each coupled to a radio frequency (RF) interface, and a self-interference canceller (SIC). The SIC is coupled between the transmit and the receive paths. The SIC is configured to cancel a self-interference signal from a received signal on the receive path based on a transmit signal on the transmit path.