Phase-Coded FMCW Radar Waveforms for Multi-Radar Coexistence

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Solution Overview

Problem

Radar systems in vehicles experience interference from nearby vehicles' transmissions, degrading target detection performance due to similar radar waveforms, particularly in systems with multiple radar sources in close proximity.

Innovation Solution

Implementing phase-coded frequency modulated continuous wave (FMCW) waveforms, where UEs select phase codes from a codebook to transmit radar signals, mitigating interference by using different phase codes than neighboring UEs, allowing multiple UEs to transmit while maintaining low mutual interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple radar systems transmit similar FMCW waveforms in close proximity, then radar coverage and detection capability are improved, but mutual interference increases and degrades target detection performance

Engineering Contradiction:
Improvetarget detection performanceVSAvoidinterference from nearby radar transmissions
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by assigning different phase codes to different radar transmitters. Each radar system uses a unique phase code sequence from a codebook, creating locally distinguishable signal characteristics. This allows receivers to differentiate between multiple transmitted waveforms and suppress interference from other radars while maintaining detection capability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the phase parameter of the FMCW waveform by incorporating phase codes. Instead of using identical frequency-modulated waveforms, each transmitter modifies the phase dimension by selecting different phase code sequences. This parameter differentiation enables multiple radars to coexist by transforming the phase characteristics while maintaining the fundamental FMCW detection mechanism.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If radar systems use standard FMCW waveforms for transmission, then device complexity is reduced and ease of operation is improved, but interference mitigation capability is insufficient in multi-radar environments

Engineering Contradiction:
Improveradar waveform transmissionVSAvoidmutual interference among radar sources
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent implements universality by creating a codebook of phase code sequences that can be universally applied across multiple radar systems. The same codebook structure and phase coding mechanism can be used by any number of radars in the network, providing a scalable solution that maintains ease of operation while enabling interference mitigation through standardized phase code assignment.

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

Enhances radar performance by reducing interference among multiple radar sources, enabling effective target detection in environments with numerous radar systems.

Implementation Method 1

Radar systems may be used for target detection by transmitting radio frequency waveforms and observing the reflected received waveform from the target to estimate the properties of the target.

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 2

Implementing phase-coded frequency modulated continuous wave (FMCW) waveforms, where UEs select phase codes from a codebook to transmit radar signals

Methodology Applied
Scientific EffectPhase modulation: Phase Modulation

Implementation Method 3

frequency modulated continuous wave (FMCW)

Methodology Applied
Scientific EffectFrequency modulation:

Implementation Method 4

identifies a set of chirps associated with an FMCW waveform

Methodology Applied
Scientific EffectChirp:

Data Source

PatentEP3807671B1Multi-radar coexistence using phase-coded frequency modulated continuous wave waveforms
Publication Date: 2025.11.12 QUALCOMM INC
  • EP3807671B1 patent drawingFigure 1
  • EP3807671B1 patent drawingFigure 2
  • EP3807671B1 patent drawingFigure 3

AI summary

Methods, systems, and devices for radar signaling are described. In some systems, devices may implement techniques to support coexistence for multiple radar sources using a phase-coded frequency modulated continuous wave waveform. A user equipment (e.g., a vehicle) may select a codeword (e.g., a pattern of parameters) from a codebook and may derive phase code information and waveform shape parameters from values specified in the codeword. The user equipment may apply phase modulation to at least one chirp of a waveform using the indicated phase code. In some cases, the phase-coded frequency modulated continuous wave waveform may resemble nested Zadoff-Chu sequences, where the waveform resembles a Zadoff-Chu sequence and the phase code resembles another Zadoff-Chu sequence. The phase code may support mitigating interference between radar waveforms that use the same slope and frequency offset parameters for chirps overlapping in time.