Joint Waveform/Receiver Design for Vital-Sign Detection in Signal-Dependent Interference

Abstract

This paper presents the joint design of discrete slow-time radar waveform and receive filter, with the aim of enhancing the Signal to Interference and Noise Ratio (SINR) in phase coded radar systems for vital-sign monitoring. Towards this, we consider maximizing the SINR at the input of the vitalsign estimation block, when transmitting hardware efficient Mary Phase Shift Keying (MPSK) sequences. This multi-variable and non-convex optimization problem is efficiently solved based on a Minimum Variance Distortionless Response (MVDR) filter, with the Coordinate Descent (CD) approach for the sequence optimization, and the obtained results have shown attractive interference suppression capabilities, even for the simple binary case.

Designing Interference-Immune Doppler-TolerantWaveforms for Automotive Radar Applications

“…be calculated 5 and the optimal sequence will be synthesized. Using the aforementioned setup for a generic sub-sequence index l, we calculate all the x l s pertaining to different subsequences and derive X.…”

“…RADAR has traditionally been associated with military and law enforcement applications due to its development, but it is now a common solution for civil situations. Currently, highresolution Frequency Modulated Continuous Wave (FMCW) radar sensors operating at 60GHz, 79GHz, and 140GHz with sometimes finer than 10cm range resolution are becoming integral in a variety of applications ranging from automotive safety and autonomous driving [1], [2], indoor positioning [3], [4] to infant and elderly health monitoring [5]. As the penetration of these low-cost high-performance sensors grows, the likelihood of radar signal interference and the associated ghost target problems also grows [6], [7].…”

Adaptive Nonlinear Least Squares Framework for Contactless Vital Sign Monitoring

“…Therefore, the heartbeat signal can be easily buried in the background noise or masked by the higher order harmonics of the breathing signal. This harmonic interference in the heartbeat signal has been extensively reported as one of the main issues in radar-based vital sign monitoring [19], [20], [21], [22], and as discussed in [23], depending on the signal-to-interference ratio (SIR) and the specific combination of fundamental breathing/heartbeat frequencies, most techniques fail to provide robust heart rate estimation. Furthermore, additional frequency components and intermodulation products may also be present in the recovered signal, originated from different sources including radar nonlinearities, phase-demodulation issues [24], and random body movements from the monitored subject [25].…”