The disclosure relates to a method for monitoring a motion of a subject, as well as to a corresponding system and computer program product. As part of the method, a monitoring signal is emitted towards a corresponding receiver. The motion of the subject is then detected based on a change in the received monitoring signal. Therein, the monitoring signal is emitted using a spread-spectrum technique and/or using an M-to-N and multi-antenna emitter-receiver system with a set of M transmitting antennas and a set of N receiving antennas.