DDM MIMO Radar Decoding Using AoA to Cut False Alarms

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Solution Overview

Problem

Conventional DDM MIMO radar systems face challenges in accurately detecting the position and movement of objects due to reliance on constant false alarm rate (CFAR) detection and lack of utilization of Angle of Arrival (AoA) information, leading to inefficiencies and susceptibility to phase noise.

Innovation Solution

A DDM decoding technique that leverages AoA information and spatial information, eliminating conventional peak and threshold detection steps, providing analytical closed-form solutions for false alarm probability and improving decoding speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional CFAR detection and peak detection methods are used in DDM MIMO radar systems, then the system can detect objects, but the false alarm probability increases and detection accuracy decreases

Engineering Contradiction:
Improvedetection accuracyVSAvoidfalse alarm probability
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent performs preliminary Angle of Arrival (AoA) estimation using the virtual array formed by multiple transmit and receive antennas before conducting target detection. This preliminary action exploits spatial information to establish expected signal directions, which are then used to guide subsequent detection processes and reduce false alarms by comparing detected peaks against predicted AoA locations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where the estimated AoA information from the virtual array is fed back into the detection process. The detected peak locations are compared with the predicted AoA directions, and this feedback loop enables the system to distinguish true targets from false alarms by verifying spatial consistency across multiple transmit channels.

Inventive Principle:
Principle #23Feedback

2Productivity

If conventional peak detection and threshold detection steps are used, then the detection process is straightforward, but the decoding speed is slow and computational efficiency is low

Engineering Contradiction:
Improvedecoding speedVSAvoidprocessing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent extracts and removes the conventional peak detection and threshold detection steps from the decoding process. Instead, it directly utilizes the AoA estimation results from the virtual array to identify target locations, eliminating computationally intensive intermediate steps and significantly reducing processing time while maintaining or improving detection accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical sequential detection process (peak detection followed by threshold detection) with a more efficient signal processing approach based on AoA estimation. This substitution leverages the spatial domain information from the virtual array to directly obtain target parameters, reducing the number of computational steps and improving decoding speed.

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

3Reliability

If AoA information is not utilized in the decoding process, then the system structure remains simple, but the detection performance and robustness to phase noise are reduced

Engineering Contradiction:
Improverobustness to phase noiseVSAvoidsignal processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the virtual array formed by multiple transmit and receive antennas serve multiple functions: it not only provides the spatial information needed for AoA estimation but also enables improved target detection and phase noise robustness. By exploiting the same hardware configuration for multiple purposes, the system gains enhanced performance without adding additional hardware complexity.

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

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

The proposed DDM decoding technique enhances decoding performance by reducing false alarm probabilities and improving speed compared to conventional methods, while being less susceptible to phase noise.

Implementation Method 1

Radar systems may be used to detect the range, velocity, and angle of nearby objects

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 2

receiver modules configured to receive reflections of the multiple transmit signals reflected by at least one object

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

perform a Discrete Fourier transform (DFT) of each range-Doppler cell of the range bin matrix in a channel dimension to generate an output matrix

Methodology Applied
Scientific EffectDiscrete Fourier transform:

Implementation Method 4

transmitter modules configured to transmit multiple transmit signals in accordance with a Doppler Domain Multiplexing (DDM) scheme

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentUS12474442B2Doppler division multiplexing (DDM) multiple-input multiple-output (MIMO) radar system and decoding method
Publication Date: 2025.11.18 NXP BV
  • US12474442B2 patent drawing
  • US12474442B2 patent drawing
  • US12474442B2 patent drawing

AI summary

A radar system may include transmitter modules configured to transmit multiple transmit signals in accordance with a Doppler Domain Multiplexing (DDM) scheme, receiver modules configured to receive reflections from the plurality of transmit signals reflected off an object and to generate corresponding digital signals, and a signal processor configured to generate a range-Doppler antenna cube representing the digital signals, and, for each of range bin of the cube, to generate a decoded range-Doppler bit map (RDBM) from the range-Doppler antenna cube by generating decoded RDBM rows by extracting a range bin matrix, performing a Discrete Fourier Transform on range bin matrix to generate an output matrix, determining peak locations in the output matrix, comparing associated peak locations across transmit channels of the output matrix to identify location-matched peaks associated with the Doppler bin, and generating a decoded RDBM row based on the location-matched peaks.