WLAN中支持实时业务的自适应调度机制

针对IEEE 802.11e无线局域网参考调度算法分配定长的发送机会（TXOP）的缺陷，提出了一种支持实时业务的自适应调度机制。该机制通过终端反馈业务流发送队列的缓存数据量，动态分配变长TXOP以满足不同负载、不同业务的要求；当有新业务请求加入系统时，调度机制在保障现有业务最低时延的前提下，采用按比例减少现有业务的请求TXOP时间的长度的方式，并采用线性规划的优化方法，尽可能为新业务安排时间允许接入。详细的仿真实验及与IEEE 802.11e参考调度机制的比较表明，提出的调度机制提高了系统的吞吐量，有效地降低了实时业务的时延。

Adaptive scheduling scheme to support real-time traffic in wireless local area networks

To overcome the defect of IEEE 802.11e reference scheduler allocating fixed Transmission Opportunity (TXOP) duration, an adaptive scheduling scheme was proposed to support real-time traffic. The proposed scheduler dynamically allocated variable TXOP duration based on the traffic load information of the amount of buffered frames in each traffic stream queue sent by stations, to satisfy the requirements of different traffic under different load. By guaranteeing minimum delay of traffic, the scheduler tried to allocate TXOP for the new arrival traffic with proportional request reduction and linear programming. Detailed simulation results and comparison with IEEE 802.11e reference scheduler prove that the proposed scheduling scheme not only improves system throughput, but also decreases delay of real-time traffic.