Efficient Packet Scheduling Schemes for Multiantenna Packet Radio Downlink

In this paper, we propose fairness-oriented dual-stream multiple-input multiple-output (MIMO) packet scheduling schemes for future multi-antenna packet radio systems. In general, multi-user transmit-receive schemes allow users to be scheduled on different parallel streams on the same time-frequency resource. Based on that, implementations of more intelligent scheduling schemes that are aware of the instantaneous state of the radio channel require utilization of time, frequency and spatial domain resources in an efficient manner. Stemming from the earlier advanced proportional fair (PF) scheduler studies, we extend the developments to dual-stream MIMO packet radios. Furthermore, we investigate the resulting fairness distribution among users together with efficiency in increasing the system capacity in terms of throughput and coverage by simulating practical orthogonal frequency division multiple access (OFDMA) system environment with MIMO functionality in micro and macro cell scenarios. As a concrete example, we demonstrate that by using new multi-user scheduling schemes, significant coverage improvements in the order of 30% can be obtained at the expense of only 14% throughput loss. Furthermore, the user fairness is also greatly increased, by more than 18%, when measured using Jainpsilas fairness index.