中文摘要：

针对正交频分多址接入（OFDMA）系统下行链路的混合业务调度问题，提出了一种基于队列等待时间的跨层调度算法。该算法联合利用了MAC层的队列等待时间与物理层的信道状态信息作为调度参数，通过队列等待时间反映用户的服务质量要求，并利用多用户分集增益提高系统性能；针对实时和非实时用户的不同服务质量要求，在队列等待时间的计算上采取了不同的策略；在子载波的分配过程中根据分配状态及时更新队列等待时间，使资源的利用更为有效。仿真结果表明，提出的算法可显著降低实时用户的平均时延和最大延时违反概率，同时保证了非实时用户的吞吐量需求，能够有效地支持下一代网络中混合业务的多种服务质量要求。

英文摘要：

A queue waiting time based cross-layer scheduling algorithm is proposed for downlink orthogonal frequency division multiple access （OFDMA） systems to support heterogeneous services. Given the user＇s queue state information and chan- nel state information, the proposed scheduling algorithm can guarantee quality of service （QoS） requirements for both re- al-time service and non-real-time services. The benefit is attained from scheduling heterogeneous services based on the queue waiting time to fulfill the QoS requirements and exploiting multiuser diversity to improve system performance. The queue waiting time is updated based on the subearrier allocation status to achieve effective resource utilization. The simulation results illustrate that the packet average delay and delay violation probability for real-time services and the throughput for non-real-time services are improved by the proposed algorithm.