Joint carrier and DOA estimation for multi-band sources based on sub-Nyquist sampling coprime array with large time lags

Abstract

Towards the tendency of the Massive MIMO exploitation in X-band, K-band or higher bands, it becomes increasingly urgent to develop a joint carrier frequency and Direction of Arrival (DOA) estimator under the spatial-temporal sub-sampling conditions. In this paper, we formulate a framework comprising sparse coprime arrays and low-rate ADCs equipped with flexible large coprime time delays, which not only alleviates the mutual coupling among antennas but also facilitates the system implementations. On basis of this framework, we propose a joint estimator characterized with a 3-stage source pairing procedure and a phase ambiguity removal approach, both of which are on basis of the joint singular value decomposition on the cross-correlations of the subsamples collected from two coprime sub-arrays. Numerical results show that, the proposed joint estimator exhibits superiorities over the existing joint estimators in both recovery accuracy and resolvability for densely-distributed sources, which presents vast potentials for further developments such as enlarging the user capacity in the future mobile communications.