Model Order Selection for ST-CDM FMCW MIMO Radar in Multipath Scenarios

This paper considers the problem of model order selection for the slow-time code-division multiplexing (ST-CDM) frequency-modulated continuous-wave (FMCW) multiple-input multiple-output (MIMO) radar in multipath scenarios. We derive the Bayesian information criterion (BIC) for the model order determination and prove the fact that the asymptotic property of the non-diagonal elements in a positive semi-definite (PSD) matrix is strictly governed by that of its diagonal elements. Additionally, we provide a RELAX-based maximum likelihood (ML) algorithm to estimate the direction-of-arrival (DOA), direction-of-departure (DOD) and Doppler frequency of each target in the presence of multipath problems. Finally, the effectiveness of the proposed approaches is evaluated by the provided numerical examples.