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-squarederror 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.