SCSI aided multi-beam selection for transmit correlated channels

This paper proposes limited feedback spatial division multiple access (SDMA) schemes for transmit correlated channels by using statistical channel state information (SCSI) and instantaneous channel state information (ICSI). Different from conventional codebook-based MU-MIMO scheme, the proposed multi-beam selection with single channel quality indicator (CQI) feedback (MBS-SCF) scheme determines the preferred beam vector by exploiting the SCSI and only feeds back CQI at each timeslot. The performance of the MBS-SCF scheme is nearly the same as the conventional scheme. In order to further improve the sum rate, we propose multi-beam selection with dual CQIs feedback (MBS-DCF) scheme, which determines dual statistical eigen-directions and feeds back dual CQIs at each timeslot. It will increase the opportunity to exploit multiuser diversity and multiplexing gain. Simulation results demonstrate that the MBS-DCF scheme exhibits a higher sum rate than the conventional scheme does.