Exploiting Multiuser Spatial Diversity in MIMOOFDM System through Uplink Scheduling

Through exploiting the multiuser diversity, the capacity of MIMO-OFDM system can increase dramatically. In multiuser singular value decomposition (MU-SVD) based MIMO-OFDM system, the scheduler can allow multiple users to simultaneously transmit independent data to base station (BS) on the same subcarrier and the data can be separated in space domain at the BS. In this paper the effect of the correlations between the singular vectors in a MU-SVD based system was investigated, and propose a greedy scheduling algorithm based on MU-SVD. Given a set of users, the algorithm finds the best and most orthogonal spatial subchannels, in order to exploit the multiuser spatial diversity. The simulation results show that if the user data are transmitted on the maximum singular mode (MSM), the amplified noises on the spatial subchannels may lead to the degradation of the system performance, however the proposed algorithm can greatly increase the system capacity.