Proportional Fairness for MIMO Multi-user Schedulers with Traffic Arrival Process

Packet scheduling at the data link layer may impact significantly the overall performance of a wireless system using multiple antennas. In this paper, we propose a novel packet scheduling scheme based on proportional fairness that considers the traffic arrival process with different packet lengths for the downlink of multiple-input multiple-output (MIMO) multi-user systems. We also provide analysis for the fairness of the new scheme in terms of time and service allocation. The scheduler, referred to as clock-time proportional fairness (C-T PF), performs at the packet level and can provide low average packet transmission delay as well as time and service fairness to users. It is work conserving and it can also take into consideration different users guarantees (heterogeneous users). We investigate an ideal service fair scheduler called C-T max-min for MIMO systems as well. We compare the performance of C-T PF with other MIMO schedulers. For the time and service fairness comparison of MIMO schedulers, we also propose time and service indexes. Simulations that consider the traffic characteristics and the mobility of users show the low average packet transmission delay and demonstrate the time and service fairness capabilities of C-T PF.