Wideband RF Interference Cancellation via Signal Segmentation

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Solution Overview

Problem

Conventional simultaneous transmission and receiving systems face saturation issues due to leakage and reflections, which prevent proper operation by saturating the receive path.

Innovation Solution

A wideband RF interference cancellation system that splits an electronic reference signal into band signals, using band pass filters and tunable cancellation elements to cancel reflections before they enter the receiving element, employing feed-forward cancellation techniques in both frequency and time domains to mitigate interference and maintain linearity from the RF front-end to digital signal processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If simultaneous transmission and receiving is implemented, then system functionality is improved, but leakage and reflections saturate the receive path

Engineering Contradiction:

Improvesimultaneous transmission and receiving capabilityVSAvoidreceive path operation

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The receive path is segmented into multiple stages with intermediate cancellation points. The cancellation unit is inserted between the LNA and first mixer to cancel leakage and reflections before they saturate subsequent stages, preventing system-wide failure while maintaining simultaneous Tx/Rx capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A cancellation unit is introduced as an intermediary component between the LNA and first mixer. This unit generates cancellation signals that are combined with the received signal to neutralize leakage and reflections, allowing the receive path to operate reliably during simultaneous transmission and receiving

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If leakage cancellation is performed at the first gain stage, then saturation is prevented, but system complexity increases

Engineering Contradiction:

Improvereceive path operationVSAvoidcancellation system structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Leakage and reflection cancellation is performed preliminarily at the first gain stage (LNA) before the signal proceeds to subsequent mixing and processing stages. By canceling interference early in the receive path, the system prevents saturation of downstream components and maintains linear operation throughout the entire signal chain

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The cancellation unit employs feedback mechanisms where a portion of the transmitted signal is captured, processed through variable gain amplifiers and phase shifters, and combined with the received signal. This feedback-based cancellation approach dynamically adapts to compensate for leakage and reflections, achieving reliable simultaneous Tx/Rx operation

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS9479214B2Wideband active radio frequency interference cancellation system

Publication Date: 2016.10.25 RAYTHEON CO

AI summary

A wideband radio frequency (RF) interference cancellation system includes an electronic channel canceller configured to split an electronic reference signal output from an electronic transmitting element into a plurality of band signals. At least one electronic band pass filter is configured to receive a respective band signal delivered to a respective channel. The wideband RF interference cancellation system further includes at least one electronic tunable cancellation element configured to tune the respective channel such that reflections are canceled before being input to receiving element.