Linear precoding for MIMO transmission with partial CSIT

We have previously introduced linear precoding schemes for spatial multiplexing, based on spatial spreading and delay diversity. These schemes were designed for the case of absence of channel state information at the Transmitter (CSIT) (whereas at the receiver the coherent case of full CSIR is assumed). These spatiotemporal spreading schemes have been shown to allow to attain the optimal rate-diversity trade-off at high SNR. On the other hand, the capacity achieving solution for the case of full CSIT is based on spatial prefiltering with water filling on the streams. Extensions of this scheme have been proposed recently for the case of partial CSIT, but like the full CSIT schemes, they do not take advantage of maximal diversity. In this paper a combination of the solutions described above for no and full CSIT is proposed for the general case of partial CSIT, exploiting diversity sources in all cases of CSIT.