Robust Coprime MIMO System Based on New Transmit-Receive Configurations

Increasing the uniform degrees of freedom (uDOFs) and minimizing the mutual coupling effects of the MIMO system have remained the core focus for the localization of the targets in communications. The MIMO systems use a duplicate-and-shift (DS) process based on a moving period to generate the difference co-array of the sum co-array (DCSC) and observe enhanced uDOFs. This letter introduces new transmitting (Tx) and receiving (Rx) configurations for a robust coprime MIMO (RCA-MIMO) system. First, the Tx and Rx apply a novel two-step remove and reconfigure (RR) technique to the existing scheme, discarding the redundant Txs/Rxs and effectively reconfiguring their locations. Then, based on these new configurations, the moving period for DS is determined, which perfectly aligns the holes and virtual lags in the adjacent periods with fewer overlapping lags. As such, not only is a longer hole-free DCSC generated with uDOFs higher than the related strategies, but the RCA-MIMO system also reduces the impact of mutual coupling. Simple closed-form expressions are also derived for element placements and uDOFs. Performance comparison confirms the superiority of the proposed RCA-MIMO over existing coprime MIMO systems.