Two Stage Detection For Uplink Massive Mimo Mu-Scma Systems

In this paper, we propose a two stage multiuser detection scheme: a linear pre-filtering and iteration removal based message passing algorithm (RM-MPA). As the first stage of the proposed detection, a linear pre-filtering based on Richardson method is proposed to avoid the complicated matrix inversion in an iterative way. Meanwhile, we also present a sub-optimum relaxation parameter to Richardson for lower-complexity. Then the RM-MPA is used for multiuser decoding, which compared the decoding advantages of users and sorted users according to decoding advantages. After the each iteration, the users with higher decoding advantages directly are decoded and removed. The removed users do not participate in the subsequent iterations, therefore, the complexity of subsequent iterations decrease gradually. Simulation results show that the proposed two stages multiuser detection can significantly reduce the computational complexity with better symbol error rate performance.