基于动态令牌轮询提供视频QoS保证的无线ATM多址接入控制  

A Dynamic Token-Polling Based Multiple Access Control Guaranteeing VBR Video QoS in Wireless ATM Networks

作　　者：庞昆[1] 郑君里[1] 顾学道[2] 

机构地区：[1]清华大学微波与数字通信国家重点实验室,北京100084 [2]信息产业部电信科学技术研究院,北京100083

出　　处：《电子学报》1999年第S1期33-37,共5页Acta Electronica Sinica

基　　金：国家高科技 863项目资助课题;日本富士通研究所资助课题

摘　　要：本文提出了一种基于动态令牌轮询调度算法 (DTSA)的无线多址接入控制 (MAC)机制 ,该方案应用于无线ATM系统 ,为多媒体业务提供了服务质量 (QoS)保证的无线接入 .基站控制器为每个ATM连接建立令牌模型 ,根据模型进行时隙分配 .为了适应诸如压缩视频流等实时VBR业务的动态特性和严格的QoS要求 ,定义了移动站用于通知基站其源帧率变化及队列情况的紧急消息 .一旦收到紧急消息 ,基站将分配一定数目的令牌进入紧急令牌队列 .根据结合紧急令牌队列的令牌轮询调度机制 ,基站可以进行灵活的时隙分配 .通过仿真计算 ,我们发现该机制能较大地提高实时VBR业务的时延和丢失性能 .This paper proposes a dynamic token polling scheduling algorithm (DTSA) based MAC scheme for wireless ATM networks. Token model of every connection is constructed in the base station for slot allocation. In order to deal with dynamic nature and stringent QoS requirement of rt VBR such as compressed video, emergency message is defined to inform the base station of the source's rate variation and buffer status. After receiving emergency message, the scheduler in base station computes out the number of slots required by the source and puts tokens into emergency token buffer, which has higher nonpreemptive priority over those of other rt VBR. By including emergency token buffer into scheduling scheme, more flexible and timely slot allocation scheme is developed. Through simulation results, we find that the scheme proposed can achieve better performance of delay and loss for rt VBR video. Also, we discuss the parameters that affect the performance.

关 键 词：无线ATM 多址接入控制 服务质量 VBR视频 

分 类 号：TN915[电子电信—通信与信息系统]