文档介绍：无线通信系统中的Qos调度综述
李磊
南京邮电大学通信与信息工程学院1213012103;江苏南京;210003
摘要:由于信道的衰落和阴影效应的存在,无线网络的信道状态是时变的。在某个给定时间,不同的移动用户经历的信道状态是不同的。因此当许多不同用户独立衰落时,肯定有一些用户经历比较好的信道状态,如果仅允许这类用户进行数据传输,就可以最大限度的利用共享的信道资源并且最大化系统吞吐量。如果所有用户的服务要求是机动的,这种调度机制就可以获得更高的频谱效率。为了在实际系统中实现这种调度,需要考虑下面的问题:公平性和用户的服务要求。如果只允许靠近基站的用户进行数据传输,这样虽然获得了高吞吐量,但是却是以牺牲别的用户为代价的。一个好的调度策略不仅仅要考虑长期的平均吞吐量,还要考虑实际系统的用户不同的服务约束。本文将简要介绍几个不同的无线通信系统中的QOS调度方案,这些方案从不同的角度入手,对基本的调度算法进行了改进,改善了无线网络的性能。
关键词:服务质量,调度,加权公平队列,公平性,吞吐量
A Review of Qos Scheduling in Wireless Systems
LI Lei
Institute munication and Information Engineering, Nanjing University of Post and munication1213012103; Nanjing Jiangsu; 210003
Abstract:In works, the channel conditions are time-varying due to the fading and shadowing. Different wireless users experience different channel conditions at a given time. When there are many users which fade independently, at any more time there is a high probability that some of the users will have a strong channel. By allowing only those users to transmit, the shared channel resource is used in the most efficient manner and the total system throughput is maximized. If the service requirement of all the users are flexible, such scheduling algorithm can result in higher spectrum utilization, and increased system throughput. In order to implement such scheduling in a real system, two issues need to be addressed: fairness and users’ service requireme