MIMO Ambiguity Function Enhancement for Integrated OFDM Communications and Sensing

Abstract

<p>Utilizing a multiple-input multiple-output (MIMO) communication transceiver to perform sensing is critical in future mobile communication systems. To improve sensing performance, the MIMO ambiguity function (AF) of such a system should ideally have a thumbtack shape, which improves target detection while minimizing the ambiguities observed in delay, Doppler, and angle profiles. Hence, this article analyzes the MIMO AF of orthogonal frequency-division multiplexing (OFDM) waveforms. We illustrate that using the MIMO transmitter for conventional single-stream OFDM communication results in high ambiguities in the MIMO AF's angle profile. As a solution, we propose to reduce the ambiguities by incorporating independent radar streams together with the communication stream. Numerical results depict that this method significantly reduces the integrated side-lobe level of the angle profile. Further, the power allocation between the two types of streams can be controlled to obtain an optimal trade-off between communication and sensing.</p>