Multi-user detection scheme for SCMA systems based on iteration removal

A multi-user detection scheme based on iteration removal (RM-MPA) was proposed to solve the problem of high complexity of decoding algorithm for sparse code multiple access (SCMA) systems.Firstly,a simple and novel method to compare the decoding advantages between users was proposed.Then n users in front of them with higher decoding advantages directly decoded and removed after each iteration,the users removed no longer participate in the subsequent iteration,so the complexity of subsequent iterations decreased gradually.Moreover,two iteration removed strategies based on decoding advantages of users and orthogonal user grouped were proposed respectively.Simulation results show that the RM-MPA with removed strategies based on orthogonal user grouped,which can reduce the decoding complexity with well decoding performance,and the decoding delay is also decreased.