A Novel Multi-User MIMO Scheme in OFDM Systems

Multi-user MIMO (MU-MIMO) is the technique which used in the scenarios with a large number of users to be served in one cell, and high capacity gains can be achieved by transmitting independent data streams to different users sharing the same time-frequency resources. Because more than two users share the same time-frequency resources in MU-MIMO systems, there is a big problem for the receiver to cancel the interference of the other users. Inspired by the idea of interference cancellation in CDMA systems, a novel multi-user MIMO scheme is proposed in this paper. It employs spreading in the transmitter and joint detection (SP-JD) in the receiver. Simulation results show that SP-JD scheme could achieve higher sum rates capacity and better bit error rate (BER) performance than Zero-Forcing (ZF) scheme while the receiver is not aware of the precoding vectors applied to the streams transmitted to the other users.