Adaptive Successive Interference Cancellation in Cell-free Massive MIMO-NOMA

This paper proposes a novel successive interference cancellation method to enhance the ergodic spectral efficiency of a cell-free massive multiple-input multiple-output (MIMO) system with non-orthogonal multiple-access (NOMA). Unlike the majority of existing research works on performance evaluation of NOMA, which assume perfect channel state information and perfect data detection for successive interference cancellation, we take into account the effect of practical (hence imperfect) successive interference cancellation (SIC). We show that the received signal at the backhaul network of a cell-free massive MIMO-NOMA system can be effectively treated as a signal received over an AWGN channel. As a result, a discrete joint distribution between the interfering signal and its detected version can be analytically found, from which an adaptive SIC scheme is proposed to improve performance of interference cancellation.