A Novel Precoder Design for MIMO Multicasting with MMSE-DFE Receivers

A novel precoding scheme is proposed for MIMO multicasting systems, using the criterion of maximizing the minimal signal-to-interference-plus- noise ratio (SINR) among multiple data streams, while considering the minimum mean-squared-error decision feedback equalizer (MMSE-DFE) at each user side. We decompose the precoding matrix into a transformation matrix multiplied by a unitary matrix, and perform the design process within two steps. In the first step, the transformation matrix is obtained by solving a convex optimization and using Gaussian randomization. In the second one, the unitary matrix is iteratively optimized by decomposing the original multiple-stream problem into several simplified dual-stream sub-problems. At each iteration, the dual-stream sub-problem is converted into a real-valued optimization problem equivalently, which can be solved by an iterative approach based on the Lozano´s algorithm. Simulation results indicate that the proposed scheme achieves better performance in terms of both achievable rate and symbol error rate than the other existing schemes.