QoS aware schedulers for multi-users on OFDMA downlink: Optimal and heuristic

Abstract

Orthogonal Frequency Division Multiple Access (OFDMA) has been adopted in the newest fifth generation radio networks (5G) such as Cloud Radio Access Networks (C-RANs) and Heterogeneous Cloud Radio Access Networks (H-CRANs). Therefore, new scheduling strategies should be projected. In 5G radio networks, restricted requirements must be considered to implement an effective service to users such as throughput, delay, packet loss, and fairness. Despite efforts to solve the downlink (DL) scheduling problem on wireless networks, we are not aware of previous attempts that have addressed the above requirements together, and more than that, in overbooked scenarios. In this paper, we address the radio DL resource scheduling problem for multiple users using LTE networks as a case study. A new optimal scheduler is modeled regarding Quality of Service (QoS) provisioning through delay. In addition, a parameterized heuristic based on user channel quality and service delay is proposed to reach scheduling solutions for overbooked scenarios. Results demonstrate that the proposed scheduling approaches led to a throughput of 7.5% lower than the optimal ones and 25% lower packet losses in overbooked scenarios. Our model also ensure that the resultant scheduling be as fair as 0.91 (according to Jain fairness index). Additionally, the obtained results show a reasonable trade-off between spectral efficiency and QoS metrics.