Abstract: Aiming at the shortage of the simple scheduler algorithm of HCCA mechanism in IEEE 802.11e, this paper designs a new upstream bandwidth allocation algorithm called E-HCCA（Enhanced HCCA） which is based on service level. E-HCCA takes different strategies on different priorities of services, that is, the Constant Bit Rate（CBR） service of all nodes is prior to served, and then excess bandwidth are shared with the Variable Bit Rate（VBR） service of all nodes according to traffic. Compared with the simple scheduler algorithm, E-HCCA can better support voice and video traffic streams in multi-user environment, reduce the packet delay and increase the whole system throughput.

Key words: IEEE 802.11e, Hybrid coordination function Controlled Channel Access（HCCA）, dynamic bandwidth allocation, Quality of Service（QoS）

摘要： 分析了IEEE 802.11e协议HCCA信道接入机制下的简单带宽调度算法对多媒体业务的QoS支持情况，指出其不足并在其基础上进行了改进，提出了一种基于业务等级的带宽调度算法E-HCCA（Enhanced HCCA）。E-HCCA对不同优先等级业务的数据在带宽分配上采用不同的策略，在优先保证各个节点CBR业务的基础上，根据节点的VBR流量动态平均分配剩余带宽。相比较简单调度算法，E-HCCA算法更好地支持了多用户下的语音业务流和视频业务流，降低了分组时延，增加了系统吞吐率。

关键词: IEEE 802.11e, 混合协调功能控制信道访问（HCCA）, 动态带宽分配, 服务质量（QoS）