Radar Self-Interference Reduction via Calibration

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Solution Overview

Problem

Radar systems face self-interference issues due to the close proximity of transmitters and receivers, leading to misidentification or misdetection of objects.

Innovation Solution

The radar system operates in two modes: calibration and sensing. In the calibration mode, it transmits test signals to estimate channel responses, which are then used to generate self-interference correction signals in the sensing mode, reducing the impact of self-interference on received signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the radar system places transmitters and receivers in close proximity to achieve compact design, then the device size is reduced, but self-interference increases causing misidentification or misdetection of objects

Engineering Contradiction:
Improveradar system sizeVSAvoidobject detection accuracy
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The system performs preliminary calibration by transmitting calibration signals before actual object detection to characterize the self-interference channel. The processor determines calibration signals, transmits them, receives reflected calibration signals, and processes these signals to determine channel responses that describe the self-interference characteristics. This preliminary characterization enables subsequent correction during actual sensing operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from received calibration signals to determine channel responses that describe self-interference. The processor receives reflected calibration signals, processes them to determine channel responses, and then uses these responses to correct subsequent received signals. This feedback loop enables the system to adapt to and compensate for self-interference effects in real-time.

Inventive Principle:
Principle #23Feedback

2Power

If the radar system transmits high-power sensing signals to improve detection range, then the detection capability is enhanced, but self-interference from transmitter leakage to receiver increases

Engineering Contradiction:
Improvetransmitter powerVSAvoidself-interference level
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The system extracts and separates the self-interference component from the total received signal. By determining channel responses that specifically characterize the self-interference path, the processor can isolate and remove this harmful component from the received signals, allowing high-power transmission without the full brunt of self-interference degradation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system converts the harmful self-interference effect into a useful characterization of the transmission channel. By measuring the calibration signals and processing the reflected calibration signals to determine channel responses, the system transforms the self-interference phenomenon into actionable information that enables correction and improves overall system performance.

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

Data Source

PatentEP4556940A1Self-interference reduction for radar systems
Publication Date: 2025.05.21 NXP BV
  • EP4556940A1 patent drawingFigure 1
  • EP4556940A1 patent drawingFigure 2
  • EP4556940A1 patent drawingFigure 3

AI summary

A radar system includes a first transmitter channel and a first receiver channel. In a first mode of operation the radar system determines a first channel response. In a second mode of operation, the radar system modifies a received signal based on the first channel response.