Joint Queue Control and User Scheduling in MIMO Broadcast Channel under Zero-Forcing Multiplexing

This paper studies the problem of queue control and user scheduling in multi-antenna broadcast (downlink) systems under zero forcing beamforming (ZFBF) transmit strategy. In the system, we assume that the data packet arrives randomly to the buffered transmitter. By taking the broadcast channel as a controlled queueing system, we deduce the property of queue control function which maximizes the weighted system throughput while guarantees the delay fairness among users. We also present a low complexity user selection algorithm with the consideration of queue state and channel state together. Simulation results show that the joint queue control and user selection policy can achieve considerable fairness and stability among users.