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.