Linear receivers for joint space-time decoding and interference rejection in multiuser uplink MIMO communication systems

We address the problem of joint space-time decoding and multiaccess interference (MAI) rejection in multiuser multiple-input multiple-output (MIMO) wireless communication systems. We study the case when the receiver and multiple transmitters are equipped with multiple antennas and when each transmitter uses orthogonal space-time block codes (STBCs) to send data to the receiver. Two new linear receivers are developed to decode the data sent from the transmitter-of-interest while rejecting MAI, self-interference and noise. The proposed receivers are designed by minimizing the output power subject to constraints which zero-force self-interference and/or preserve a unity gain for all symbols of the transmitter-of-interest. Simulation results show that in multiaccess scenarios, the proposed techniques have substantially lower symbol error rates as compared to the matched filter receiver which is equivalent to the maximum likelihood space-time decoder in the point-to-point MIMO communication case. Our numerical examples also show that in application to joint space-time decoding and MAI rejection, using zero-forcing constraints to eliminate the self-interference can improve the performance of the linear receiver.