Multiuser MIMO Transmission in Distributed Antenna Systems with Heterogeneous User Traffic

In this paper, we consider multiuser transmission in the downlink of a distributed antenna system with two types of users: i) the real-time users that require a minimum instantaneous rate and ii) the best-effort users that try to maximize their rates. We start with a two-user system consisting of one real-time user and one best-effort user, in which the optimal beamforming scheme is proposed to maximize the instantaneous rate of the best-effort user under the rate constraint of the real-time user and per-antenna-power constraint. Two suboptimal transmission schemes are then proposed to reduce the computational complexity and feedback overhead, respectively. Furthermore, we propose a round-robin based scheduler to extend the proposed schemes to a general multiuser system, such that the outage probability of the real-time users is minimized. System-level simulation results show that the proposed schemes have better performance than two reference schemes.