Losing Opportunism: Evaluating Service Integration in an Opportunistic Wireless System
Losing Opportunism: Evaluating Service Integration in an Opportunistic Wireless System
复制标题
DOI：
10.1109/infcom.2007.119
复制
发表时间：
2007-05
期刊：
影响因子：
--
通讯作者：
Hongseok Kim;G. Veciana
中科院分区：
文献类型：
--
作者：
Hongseok Kim;G. Veciana
在本文中，我们使用机会调度来评估在无线系统中集成服务质量和尽力而为流时流级性能度量之间的交互作用。我们引入了一个简单的流级模型，该模型捕捉了机会调度器的带宽共享的显著特征，该模型确保了每个时隙对每个QOS流的平均吞吐量。然后，我们对流级性能进行了研究，结果表明，服务质量和尽力而为流的集成会导致机会主义的丢失，进而导致稳定区域的减小、系统吞吐量的降低和文件传输延迟的增加。在瑞利衰落信道模型下，这些损失与机会收益、保证的带宽和服务质量流的数量成正比，但与信噪比成反比。在利用机会主义的集成系统中，本地不稳定似乎比有线网络中更严重，尽力而为流所经历的平均延迟被延长。我们建议，有必要对尽力而为的数据流进行某种形式的准入控制，以避免局部不稳定，并确保足够的性能。
In this paper we evaluate interactions among flow-level performance metrics when integrating QoS and best effort flows in a wireless system using opportunistic scheduling. We introduce a simple flow-level model capturing the salient features of bandwidth sharing for an opportunistic scheduler which ensures a mean throughput to each QoS stream for every time slot. We then explore the flow-level performance showing that integration of QoS and best effort flows results in loss in opportunism, which in turn results in a reduction of the stability region, degradation in system throughput, and increased file transfer delay. These losses are shown to be proportional to opportunistic gains, the guaranteed bandwidth and number of QoS flows, but inversely proportional to SNR under a Rayleigh fading channel model. In an integrated system exploiting opportunism, local instability appears to be more severe than in wired networks and average delays experienced by best effort flows are prolonged. We suggest that a form of admission control for best effort flows is necessary to avoid local instability, and ensure adequate performance.