A Fixed Group based Transmission Scheme with Limited Feedback in downlink Multiuser MIMO Systems

In downlink multiuser MIMO schemes, multiuser interference (MUI) can be suppressed by ZF-precoding or BD methods. However, the quantization errors in channel information feedback leaves remained MUI, which is proportional to SNR and thus deteriorate system performance. In this paper, a fixed group based receiver multiuser interference cancelation scheme is proposed to eliminate the remained MUI. In this scheme, codewords are grouped by base station (BS). The grouping information is broadcast to terminals and is fixed during transmission. In scheduling, BS chooses the users with codewords in one group as MU-MIMO receivers. Therefore, terminals have knowledge of the codewords of their interfering users, and the remained MUI can be canceled by two proposed schemes, decorrelation and MMSE scheme. The proposed scheme is compared with multiuser or single user ZF-precoding schemes by simulations. Numerical results show that the proposed scheme achieves significant performance improvement in terms of BER and throughput.