Achieving Diversity-Multiplexing Tradeoff in Finite-Rate Feedback Multi-Antenna Systems with User Selection

This paper investigates the user selection strategy in multiuser downlinks using zero-forcing beamforming (ZFBF) and finite-rate feedback (FRF). In order to mitigate the interference-limited effect, we propose an efficient user scheduling scheme combined with adaptive transmission mode selection to achieve a better diversity and multiplexing tradeoff in terms of the sum rate performance. In this scheme, each user first evaluates its preferred transmission mode and the corresponding achievable rate according to a derived tight lower bound to the rate. Given such information available through feedback, the base station then determines the global transmission mode of the system and selects users for simultaneous transmissions. Simulation results demonstrate the performance of our proposed scheme.