Blind polarization oblique projection based inter-user interference cancellation in full duplex multiuser MIMO system

In full duplex (FD) multiuser MIMO system, multiple mobile stations (MSs) with FD transmission simultaneously access a given base station (BS), significant interuser interferences exist, limiting FD system performance. Existing methods addressing in the inter-user interference cancellation mostly need to know the interference channel state information and to decode and subtract the interference from the receiver. In this paper, we propose a blind polarization oblique projection based inter-user interference cancellation method without any prior information of the interference channel. This method merely utilizes the polarization state (PS) information and the autocorrelation matrix information of received signals at the downlink MS receivers to construct an oblique projection operator, which can be used to project the inter-user interference to the null space of the operator. Numerical results demonstrate that the proposed method can cancel the inter-user interference effectively when compared to the system with inter-user interference existing, and it performs more robust when the signal to noise ratio (SNR) and the receive antennas number is small.