TH precoding based multiuser spatial multiplexing scheme in MIMO systems

Tomlinson-Harashima precoding (THP) is a nonlinear, successive pre-equalization technique. A THP-based multiuser spatial multiplexing scheme was developed to improve the system capacity in multiple-input multiple-output (MIMO) systems. In this scheme, the receivers perform beam-forming, while the transmitter suppresses the inter-user interference using the THP scheme. A theoretical analysis and simulation results indicate that, compared with the traditional singular value decomposition (SVD) based single-user spatial multiplexing and linear zero-forcing (ZF) based multiuser spatial multiplexing, the scheme obtains larger equivalent channel gains and system capacity, and at the same time, guarantees user fairness.