Impact of an Automotive Chirp-Sequence Interferer on a Wideband OFDM Radar

Knill, Christina; Schweizer, Benedikt; Hügler, Philipp; Waldschmidt, Christian

doi:10.23919/eurad.2018.8546524

Cited by 10 publications

(9 citation statements)

References 8 publications

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“…This can be the time domain for FMCW to FMCW interference [25]- [27] or the spectrogram for FMCW to OFDM interference. For the latter, the energy gets compressed to only a few modulation symbols that can easily be zeroed out or reconstructed [2]. As analyzed in the previous chapter, OFDM interference is a wideband, noise-like signal and it remains noise during the evaluation, where it is eventually spread over the complete rv-map.…”

Section: Interference Mitigation a Evaluation Of Conventional Mitigation Methodsmentioning

confidence: 99%

“…So far, the research mainly focuses on interference between digital and analog radar sensors. The influence of a chirp-sequence frequency-modulated continuous-wave (FMCW) radar on an orthogonal frequency-division multiplexing (OFDM) radar is studied intensively in [2]. It is shown that the instantaneously narrowband chirp signal is easily detectable in the wideband OFDM frame and the interfering energy can be removed by simple methods.…”

Section: Introductionmentioning

confidence: 99%

“…Chapter IV and Chapter V describe and quantize the effects of interference followed by mitigation strategies in Chapter VI. It is shown that conventional mitigation techniques as used in [2], [4] are not applicable. Therefore, the use of adaptive digital beamforming is proposed, and two implementations based on reference signal generation and constant modulus algorithm (CMA) are given in Chapter VI-B as a universal mitigation method.…”

Section: Introductionmentioning

confidence: 99%

“…Zeroing: The amplitude of the interfered cell is set to zero 2. Amplitude rescaling: The amplitude of the interfered cells is reduced to the amplitude without interference based on signal statistics to reduce the rectangular amplitude pattern.…”

mentioning

confidence: 99%

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Mutual Interference of Automotive OFDM Radars—Analysis and Countermeasures

Schweizer¹,

Knill²,

Werbunat³

et al. 2021

IEEE J. Microw.

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Due to its noise-like signal property, digital orthogonal frequency-division multiplexing (OFDM) radars are often assumed to be robust against interference. While a lot of research has been carried out for interference between different modulation schemes, the mechanisms of interference from OFDM to OFDM radars have been barely addressed. This paper provides a thorough analysis of mutual OFDM to OFDM interference based on radar measurements using a 4x4 77 GHz multiple-input multiple-output (MIMO) OFDM radar prototype. The effects of interference are described both qualitatively and quantitatively for cyclic-prefix and stepped-carrier OFDM. Second, it is shown that conventional mitigation methods in the spectrogram are not suitable due to the random coding of cyclic-prefix OFDM. As an alternative, the application of adaptive beamforming is proposed and two realization possibilities are provided. Finally, new mitigation strategies in the modulation domain are proposed. They allow to shape interference to specific range-Doppler cells, yielding an interference-free range-velocity map for the area of interest. Additionally, the method may be used as the basis to enable simple conventional interference mitigation strategies.

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Section: Interference Mitigation a Evaluation Of Conventional Mitigation Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Mutual Interference of Automotive OFDM Radars—Analysis and Countermeasures

Schweizer¹,

Knill²,

Werbunat³

et al. 2021

IEEE J. Microw.

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“…Slow-ramp FMCW disturbance in automotive radar applications is considered in [7] where a frequency domain detection and signal recovery via linear prediction is proposed. In [8] the impact of a fast-chirp FMCW radar on an OFDM radar is shown using measurements. A simple frequency domain detection and mitigation method based on signal leveling is presented.…”

Section: Introductionmentioning

confidence: 99%

Interference-Robust Processing of OFDM Radar Signals Using Compressed Sensing

Knill¹,

Schweizer²,

Waldschmidt³

2020

IEEE Sens. Lett.

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An essential prerequisite for radars in automotive applications, safety systems, future autonomous driving, and industry applications is the reliable operation even under difficult conditions such as interference from other radars. Recently, digital radar principles such as orthogonal frequency-division multiplexing (OFDM) gained increasing attention. In this letter, an interference-robust processing for OFDM radar signals using compressed sensing (CS) is presented, which is particularly suitable for random OFDM but also applicable to stepped and standard OFDM. It allows robust radar operation in presence of interfering signals that have a comparable low instantaneous bandwidth and high narrowband power. The method is validated experimentally using measurements of an OFDM radar setup at 76 GHz and a state-ofthe-art FMCW radar as an interferer.

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FMCW-Interference of Frequency Agile OFDM Radars

Knill

Schweizer

Stephany

et al. 2021

2020 17th European Radar Conference (EuRAD)

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Flawless operation even with a high density of radar sensors in the vicinity is an essential prerequisite for radar sensors in automotive applications, safety systems, future autonomous driving, and in industry applications. Recent research shows the great potential of digitally modulated radars such as orthogonal frequency-division multiplexing (OFDM). Furthermore, novel frequency agile OFDM approaches such as stepped and sparse OFDM are superior to standard OFDM as they are able to achieve high resolution beyond the hardware-related band limits. In order to prevent possible mutual interference issues of common and novel modulation schemes, the influence of a state-of-the-art FMCW on stepped and sparse OFDM is examined in this paper. The effects of interference are investigated theoretically and through measurements using an experimental OFDM setup at 76 GHz and scenarios with up to two FMCW interferers. To prevent signal deterioration and limited detection performance due to interference, an efficient but low-cost detection and mitigation approach is presented for each of the two approaches.

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Impact of an Automotive Chirp-Sequence Interferer on a Wideband OFDM Radar

Cited by 10 publications

References 8 publications

Mutual Interference of Automotive OFDM Radars—Analysis and Countermeasures

Mutual Interference of Automotive OFDM Radars—Analysis and Countermeasures

Interference-Robust Processing of OFDM Radar Signals Using Compressed Sensing

FMCW-Interference of Frequency Agile OFDM Radars

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