DFT-based vs. Cooperative MET-based MU-MIMO in the Downlink of Cellular OFDM Systems

In this work, we compare different pre-coding techniques and their performance in a cellular MIMO OFDM downlink. The first target is to determine the achievable additional beamforming gain by using a near-optium pre-coder instead of DFT-based pre-coding. In the second step, we include multi-user selection diversity, which turned out to be advantageous especially for downlink cooperation. An extended score-based scheduler, which is known to asymptotically reach proportional fairness, is used for the user grouping and resource allocation in the cellular downlink. Further, we use minimum mean square error equalization at the terminal side to combat residual cochannel interference.