A Noncoherent Differential Transmission Scheme For Multiuser Massive Mimo Systems

A noncoherent multiuser transmission scheme is proposed for massive multiple-input multiple-output (M-MIMO) systems without explicit channel estimation. In particular, each user uses differential PSK modulation and the receiver employs differential detection. First, we propose a simple user selection scheme to optimize the distributions of power space profile (PSP) of individual users which alleviates the overlap of PSPs. Then, each output stream of the weighing filter is fed into a noncoherent successive interference cancellation (N-SIC) processor, and finally into a soft-input soft-output (SISO) multiple-symbol differentialdetector (MSDD). Employing the autocorrelation receiver (AcR) and the belief propagation(BP) message passing algorithm, the proposed SISO-MSDD framework can be easily integrated with advanced channel coding. The proposed scheme bears the potential to solve the high channel estimation overhead for conventional coherent M-MIMO systems. Simulation results show that the BER performance can be significantly improved within a few iterations of the proposed scheme.