Interference-Robust Processing of OFDM Radar Signals Using Compressed Sensing

Abstract

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.

Mutual Interference of Automotive OFDM Radars—Analysis and Countermeasures

“…7 show that the SNR is similar to the non-interfered case, and only the velocity index corresponding to v = 5 m/s has an increased noise level. 4 To exploit the benefits of this scheme, the resulting interference ridge should be placed outside the actual area of interest. Common parameterizations of the OFDM modulation have a very large unambiguously measurable velocity due to the short symbol duration.…”

“…These include the removal of the interfered cells in the spectrogram (zeroing) or energy leveling in the same domain. Furthermore, compressed-sensing techniques can be used to estimate missing signal parts [3], [4], and signal repairment based on linear prediction is possible [5]. In [6] the interference from OFDM to FMCW is studied theoretically with the conclusion that OFDM interference on chirp-sequence radars can be regarded as additional noise.…”

“…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.…”

A Novel Approach to Control the Sidelobe Levels in Orthogonal Frequency Division Multiplexing Radar Waveform Design Using Broyden-Fletcher-Goldfarb-Shanno Algorithm

“…Currently radars are applied for automotive applications using multicarrier techniques [5]. The prominent features in radar signal processing are range and resolution.…”

Hybrid Beam-Steering OFDM-MIMO Radar: High 3-D Resolution With Reduced Channel Count

“…To demonstrate the system integration of the proposed front end, we implement a multichannel stepped-carrier orthogonal frequency-division multiplexing (SC-OFDM) modulation scheme. OFDM radar is widely considered to be a promising technology for many spectrally dense scenarios requiring higher flexibility than conventional analog modulation [18], and several current hardware and algorithm development trends (e.g., in the fields of analog/digital converters, field-programmable logic, and sparse reconstruction techniques [19], [20]) are working toward eliminating the remaining obstacles to its widespread usage. For this reason, our detailed discussion of the steps necessary to integrate the presented aperture into such a system, covering aspects from signal processing to calibration algorithms, will hopefully prove valuable to future system designs.…”