An Enhanced Proportional Fair Algorithm to Provide QoS over a Shared Wireless Link

Proportional Fair (PF) scheduling algorithm selects a user according to the ratio between the user current channel rate and the user average channel rate, which provides a good performance in terms of fairness. However, PF scheduler can not guarantee a Quality of Service (QoS) requirement be achieved. Moreover, if a variable bit rate (VBR) traffic is considered under different channel conditions for each user, PF scheduler performance will decrease. In this work, we propose an enhanced PF scheduling algorithm to select multiple data users with packet delays not exceeding given threshold with high probability according to the user input traffic characteristics, user current channel condition, user average channel rate and user QoS requirement. We consider the well-known effective bandwidth expression, which takes into account the user QoS requirement and the user input traffic characteristics, to select a user to be scheduled. Properties of the proposed scheduling algorithm are investigated through simulations with VBR flows and performance comparisons with PF scheduler. The results show a better performance of the proposed scheduler compared with PF scheduler.