@article{Lai2026, 
author = {Dongsheng Lai and Zhiming Cai and Ganhong Tian and Jiangchao Zhang and Long Chen},
title = {Robust multi-person vital-sign sensing in indoor environments using FMCW MIMO radar},
year = {2026},
journal = {Electronic Research Archive},
volume = {34},
number = {3},
pages = {1477-1505},
keywords = {FMCW radar, vital signs monitoring, respiration rate, heart rate, multi-subject separation},
url = {https://www.sciopen.com/article/10.3934/era.2026067},
doi = {10.3934/era.2026067},
abstract = {Contactless monitoring of respiration and heart rate in shared indoor spaces—such as hospital wards, eldercare facilities, and sleep labs—demands solutions that are unobtrusive, privacy-preserving, and robust to static reflections, multipath, and inter-subject interference. This paper presents a complete millimetre-wave frequency-modulated continuous-wave (FMCW) technology - multiple-input multiple-output (MIMO) radar framework for multi-subject vital-sign sensing with three key contributions: (i) clutter-robust target discovery to stabilize detections in realistic indoor scenes; (ii) high-resolution spatial separation to suppress inter-subject leakage; and (iii) hybrid time–frequency decomposition to improve heartbeat isolation by mitigating respiration harmonics and noise. Experiments on single-, two-, and three-subject datasets achieve Mean Absolute Error/ Root Mean Squared Error (MAE/RMSE) of 2.81/4.13 Beats Per Minute (BPM) for respiration and 2.43/3.61 BPM for heart rate. Compared with filtering-, Ensemble Empirical Mode Decomposition (EEMD), Compressive Sensing - Orthogonal Matching Pursuit (CS-OMP), and mmRH-Millimetre-wave radar heart-rate (mmRH) based baselines, the proposed framework yields substantially lower heart-rate errors while maintaining reliable multi-subject operation in shared indoor environments.}
}