Hierarchical Opportunistic Scheduling in Multi-Service OFDMA Networks

A novel hierarchy scheduling mechanism is proposed for opportunistic scheduling in multi-service OFDMA network, where the services consist of delay-sensitive (DS) services and delay-insensitive (DIS) services. To implement opportunistic scheduling (OS), we design a hybrid QoS mechanism based on the channel condition feedback from each Mobile Station. In the MAC layer, scheduler performs hierarchically. First, it will dynamically assign the necessary subcarriers to guarantee the minimal reserved traffic rate and latency requirement for DS services. Second, a utility function is employed to achieve efficient bandwidth utilization for both unmet DS services and DIS services, exploiting multi-user diversity with fairness consideration. The simulation results explicitly verify our expectation that the proposed mechanism can meet the throughput requirements without compromising latency and fairness among services with diverse QoS requirements.