Affine projection based decoder based on diagonal space-time block codes in a Multiuser MIMO downlink system

For a downlink of Multiuser (MU) Multiple-Input, Multiple-Output (MIMO) system, in this paper, new decoding methods, named as affine projection based decoders, will be proposed based on a diagonal space time block code, under assumptions that the transmitter does not have channel state information (CSI), and transmits signals simultaneously to each user. In these decoders, techniques of affine projection will be applied, and user´s interference can be eliminated completely. Moreover, the wanted signal can completely be preserved, which is different from decoders based on the orthogonal projections where this signal is damaged. Also, performances of these new decoders are analyzed. Simulations confirm our analysis.