Radar Waveform Orthogonal Sequence Sets for Interference Suppression

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Solution Overview

Problem

Current wireless systems for autonomous driving face challenges in managing interference and multipath signals, leading to unacceptable latency and inaccuracies in object detection and identification, particularly in complex operational environments.

Innovation Solution

The use of radar waveforms based on orthogonal sequence sets, specifically Zadoff-Chu sequences, for generating phase-coded waveforms that enable interference suppression and accurate Doppler estimation, allowing for low-latency and low-cost high-performance radar systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional radar waveforms are used for object detection in autonomous driving, then the system can perform basic detection functions, but interference and multipath signals cause unacceptable latency and inaccuracies in complex operational environments

Engineering Contradiction:

Improveobject detection accuracyVSAvoiddetection latency

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent changes the waveform parameters by using phase-coded waveforms generated from orthogonal sequence sets (such as Zadoff-Chu sequences) instead of traditional waveforms. This parameter change optimizes the correlation properties of the radar signals, enabling accurate detection while reducing latency caused by interference and multipath effects through superior auto-correlation and cross-correlation characteristics

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by assigning different orthogonal sequences to different radar sensors or transmission channels. Each sequence is locally optimized with specific correlation properties tailored to suppress interference from particular directions or sources, while maintaining overall system performance through the orthogonal nature of the sequence set

Inventive Principle:

Principle #3Local quality

2Area of stationary object

If radar systems transmit continuous waves for detection, then coverage area is improved, but interference management and ghost signal suppression become difficult

Engineering Contradiction:

Improveradar coverage areaVSAvoidinterference and multipath signals

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent employs periodic action through the use of orthogonal sequences with specific periodic correlation properties. The phase-coded waveforms are constructed from sequences that exhibit controlled periodic behavior, allowing the radar system to maintain continuous transmission for wide coverage while the periodic structure enables identification and suppression of repeating interference patterns and multipath ghost signals

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent converts the harmful effect of multipath signals and interference into a beneficial identification mechanism. By using orthogonal sequences with distinctive correlation signatures, the system can identify reflected and interfered signals and distinguish them from genuine target returns, effectively converting the presence of these harmful signals into an opportunity for enhanced detection through correlation-based discrimination

Inventive Principle:

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

3Speed

If digital beamforming is used to control beam direction, then directional detection capability is improved, but the system cannot manage unintended radar transmissions and echoes without unacceptable latency

Engineering Contradiction:

Improvebeam response speedVSAvoidinterference management reliability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent applies universality by designing phase-coded waveforms that simultaneously serve multiple functions: they enable digital beamforming for directional control, provide interference suppression through orthogonal properties, and facilitate rapid detection through optimized correlation characteristics. This multi-functional waveform design eliminates the need for separate interference management systems, achieving both speed and reliability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11656320B2Method and apparatus for radar waveforms using orthogonal sequence sets

Publication Date: 2023.05.23 METAWAVE CORP

AI summary

Systems, methods, and apparatus for radar waveforms using orthogonal sequence sets are disclosed. In one or more examples, a vehicle for autonomous driving comprises a radar sensor. In some examples, the radar sensor comprises a waveform transmission module adapted to generate a phase-coded waveform based on a set of concatenated orthogonal sequences. Also, in some examples, the radar sensor comprises a receiver adapted to estimate a range and Doppler from a received echo from the phase-coded waveform. In one or more examples, the orthogonal sequences are Zadoff-Chu (ZC) sequences.