The concatenation of the multiple-input multiple- output (MIMO) linear precoder with an outer forward error correction (FEC) code at the transmitter is investigated in this pa- per. At the receiver side, the turbo detection is taken into account, which iteratively exchanges the extrinsic information between a soft-demapper and a FEC soft-decoder. We firstly propose a new precoder named F_I_1 precoder thanks to the extrinsic information transfer (EXIT) chart analysis. The proposed precoder aims to optimize the iterative receiver convergence by maximizing the ending point I_1 of the soft-demapper EXIT function. For the sake of low-complexity, F_I_1 is designed for two data streams MIMO transmission only. Secondly, to cope with the higher data streams transmission, a global b = 2K data streams system is split into K two data streams subsystems. F_I_1 is then applied at each subsystem. Finally, we propose a new algorithm to optimize the inter-subsystems power allocation with the criterion is to maximize I_1 of the global system.