Layered space-time nonlinear precoding method in multi-carrier code division multiple access (MC-CDMA) system

The invention relates to a layered space-time nonlinear precoding method in a multi-carrier code division multiple access (MC-CDMA) system. The method comprises the following steps of: firstly, establishing a precoding system; adopting geometric mean resolution on feedback channel information in the system to form a product of a unitary matrix and an upper triangular matrix to obtain a precoding matrix with the same equivalent noise gain; carrying out nonlinear modular algebra precoding (THP, Tomlinson-Harashima Precoding) among MC-CDMA subcarrier channels at the transmitting end; multiplying all subcarrier signals after carrying out THP and the unitary matrix obtained by channel geometric mean resolution and then transmitting from a corresponding antenna; and processing at the receiving end by adopting a Zero Forcing (ZF) criterion or a minimum mean-squared error (MMSE) criterion. The method effectively eliminates the layer mistaking transmission effect of a layered space-time code, improves the code mistaking performance of the system, reduces the complexity of a downlink receiver and can effectively resist the selective fading of channel frequency, thereby improving the transmission performance of the system.