A novel unitary precoder design for TIMO multicasting with SIC receivers

Physical layer multicasting attracts tremendous research interests recently. In this paper, we propose a novel unitary precoder design for multicasting where two common data streams are sent to all users. With the successive interference cancelation (SIC) receivers, the two-input multi-output (TIMO) multicasting channel can be converted into two parallel sub-channels, then we focus on maximizing the minimum signal-to-noise ratio (SNR) of subchannels. In order to deal with this non-convex optimization problem, firstly the closed-form solution of SNR vectors for both subchannels is derived. And then, an efficient iterative algorithm, which is based on the Lozano's method, is investigated for the unitary precoder design. Simulation results are presented to demonstrate the superior performance of the proposed scheme over the existing algorithms.