Abstract: Considering the error propagation effect and high complexity of vertical bell labs layered space time codes，a novel nonlinear module algebra precoding algorithm based on QR decomposition for VBLAST in multi-user MIMO-MC-CDMA downlink system is proposed，QR decomposition is used for precoding matrix，the nonlinear module algebra THP precoding is used between sub-carrier channels of MC-CDMA to eliminate interference from other signals at the transmitter，and can eliminate the error propagation effect of layered space-time codes effectively.At the receiver，ZF and MMSE criterion are used for detection，and the complexity of the downlink receiver can be reduced.Simulation results show that the proposed algorithm is better than the traditional algorithms in the system BER performance.

摘要： 针对垂直分层空时方案（VBLAST）传统检测存在误层传输效应及复杂度高的问题，提出了一种多用户MIMO-MC-CDMA下行链路系统中基于QR分解的VBLAST非线性模代数预编码算法，该算法首先采用QR分解获得预编码矩阵，然后在发射端MC-CDMA子载波信道间进行非线性模代数THP预编码，可以有效地消除分层空时码的误层传输效应。在接收端采用迫零与最小均方误差准则，降低了下行接收机的复杂度。仿真结果表明，提出的算法比传统检测算法有效改善了系统的误码性能。