Integrated Sensing and Communication in User-Centric Cell-Free Massive MIMO Systems with OFDM Modulation

This paper considers the problem of integrated sensing and communications in a user-centric cell-free massive MIMO system employing OFDM modulation. It is assumed that a large number of access points is using the same frequency band in order to communicate with a certain number of mobile users and to perform surveillance against potential targets in the surrounding area. The paper develops all the needed transceiver signal processing needed to implement both the communication and radar functionality, and provides expressions for the generic user downlink SINR and for the radar SNR. Numerical results are finally presented to show the effectiveness of the proposed system and to highlight the impact on the system performance of the different power split between the communication and radar functionalities, as well as of the access points and users density in the considered area.