The integration of optical and wireless technologies, denoted as Fiber-Wireless (FiWi) networks, can provide not only high capacity but also flexible wireless access ability with less infrastructure deployment. Since data traffic generated in FiWi networks usually experiences unstable and unpredictable, it is difficult to perform traffic prediction in advance. An effective and fair Dynamic Bandwidth Allocation (DBA) scheme plays an important role. This paper proposes an upstream fair hierarchical DBA scheme for EPON-WLAN networks. Excess bandwidth proportion factor is introduced to address the unfair issue due to the unmatched problem between the allocated bandwidth resource and the assigned user weight among multiple granting cycles. On the other hand, in order to deal with the QoS guarantee and bandwidth waste issue in bandwidth allocation, we jointly taken into account of different traffic QoS priorities, bandwidth requirement proportion, and actual traffic load. Extensive simulation results show that compared with the existing DBA schemes, the proposed hierarchical DBA scheme can improve proportional fairness, throughput and channel utilization. Moreover, the proposed FiWi DBA scheme does not refer to a specific bandwidth resource types, thus obtains good generality.%光纤网络和无线接入技术结合的FiWi网络可提供高容量、灵活以及低基础设施成本的无线接入能力.由于FiWi网络中客户端业务量一般具有不稳定性,很难提前有效预测,高效公平的动态带宽分配(DBA)机制具有重要作用.该文针对EPON和WLAN构成的FiWi网络提出一种分级DBA机制.引入剩余带宽比例因子解决多个轮询周期内各用户分配的带宽资源与其权值不匹配而产生的不公平问题;联合考虑业务优先级、带宽请求比例和网络负载解决带宽分配中的业务QoS保证和信道带宽浪费问题.仿真实验表明,与现有文献的DBA机制相比,系统公平性、吞吐量和信道利用率有明显提升.且所提DBA算法不限定具体带宽资源类型,具有良好通用性.
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