A novel CQI feedback and user allocation scheme for PU2RC/OFDMA systems in correlated MIMO channels

Abstract

On the multi-antenna broadcast channel, Space division multiple access (SDMA) extracts the multiplexing gain by transmitting multiuser packets simultaneously to maximize the system throughput. This paper considers a practical design called per user unitary and rate control (PU2RC) in order to achieve the multi-user diversity (MUDiv) for SDMA with the reasonable feedback burden. However, PU2RC/OFDMA needs to feedback the preferred precoding index and its CQIs per resource unit, chunk. Moreover, it has a defect in scheduling the streams using user grouping and is difficult to achieve MUDiv fully. In order to overcome these drawbacks, we employ transmitter controlled precoding and opportunistic feedback (TCP-OFB) in conjunction with frequency scheduling for single-user and multi-user allocation. Numerical results shows that the proposed scheme achieves comparable performance to conventional PU2RC/OFDMA with a far reduced feedback load in any user allocation and antenna correlation scenarios.