Size-based Proportional Fair scheduling

In new generation cellular networks, opportunistic schedulers take advantage from the delay-tolerance of data applications to ensure that transmission occurs when radio channel conditions are most favourable. “Proportional Fair” (PF) is a well-known opportunistic scheduler that provides a good compromise between fairness and efficiency when transmitting long flows. Unfortunately, the PF algorithm is not efficient for short transfers, which represent the majority of data flows. Moreover, the lack of coordination between opportunistic scheduling and the congestion control mechanism of TCP induce very poor performance especially for short-lived flows. In this paper, we propose three enhanced scheduling approaches that significantly reduce the transfer time of short flows without a significant degradation of the QoS provided to long flows (which are much less sensitive to response time). The simulation results we present of the proposed mechanisms highlight the large benefits that can be obtained by implementing them.